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Moral-up first, immoral-down last: the time course of moral metaphors on a vertical dimension Han Lin Wanga,b, Ya Qiao Luc and Zhong Yi Lua Many abstract bipolar concepts are usually represented by metaphors on vertical dimensions (e.g. positive-up, negative-down). However, several studies have found an asymmetry in the way in which individuals process bipolar dimensions, with + polarities being stronger than − polarities. The current research focused on moral metaphors on a vertical dimension (e.g. moral-up and immoral-down) and examined the asymmetric representation of moral and immoral concepts. The first experiment showed a distinct metaphorical association between morality and vertical space, consistent with earlier research. The second experiment showed that moral and immoral words are processed differently depending on whether they are used as metaphorically congruent or incongruent vertical cues. ‘Moral-up’ association modulated the amplitudes of the N1, P2, and late positive-going potential during the processing of moral words, whereas the ‘immoral-down’ association only modulated the amplitudes of the late positive-going potential induced during the
Introduction Morality, as an abstract social concept, might not be as easily understood or represented as concrete concepts might be, and it appears to be cognitively processed in a particular way. The conceptual metaphor theory proposes that an efficient way to represent abstract concepts is by using metaphors [1]. According to this account, metaphors connect abstract concepts (the target domain) to more concrete concepts (the source domain), making the abstract concepts more understandable. Therefore, metaphors are not merely a linguistic phenomenon but also serve a goal of representation [2]. Consistent with this account, there is evidence that morality is represented in metaphors that involve concrete concepts such as brightness, color, and cleanness (e.g. [3–5]). Using these metaphors that are linked to sensation and perception, individuals might better understand complicated moral concepts. Spatial metaphors (for example, those having to do with ‘up’ and ‘down’) have an especially strong influence on concept formation. A growing body of experimental research has shown that metaphors on vertical dimensions influence a wide range of social psychological phenomena and shape how individuals conceptualize multiple aspects of the social world [6]. For example, researchers have found that there are close relations 0959-4965 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
processing of immoral words. These results suggest that asymmetry in the processing of vertically represented morality metaphors is reflected in the time course of the representation of these bipolar concepts, with the ‘moral-up’ association having an earlier effect than the ‘immoral-down’ association. NeuroReport 27:247–256 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. NeuroReport 2016, 27:247–256 Keywords: event-related potential, metaphor, moral concept, time course, vertical dimension a
School of Education, Hebei Normal University, Shijiazhuang, bSchool of Psychology, South China Normal University, Guangzhou, People’s Republic of China and cDepartment of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, Hong Kong Correspondence to Zhong Yi Lu, M.Ed., School of Education, Hebei Normal University, 050000 Shijiazhuang, People’s Republic of China Tel: + 86 0311 807 88218; e-mail: [email protected] Received 15 December 2015 accepted 17 December 2015
between positive emotions and upward sides, whereas negative emotions are linked to downward sides [7–11]. Similarly, powerfulness is usually represented at the top, whereas powerlessness is usually represented at the bottom [12,13]. These studies have shown that many abstract social concepts have close connections with spatial information, with one concept connected with ‘up’ and its polar opposite concept connected with ‘down’. Although metaphors that describe ‘up’ and ‘down’ are a common way to represent some abstract bipolar concepts, research on the vertical dimension of moral metaphors is scarce and conclusions are not fully consistent within and across studies. For instance, Meier and colleagues [8,9] found a significant implicit association between morality and the vertical dimension when using the implicit association test (IAT). They then used a space-Stroop task (that is, classifying moral and immoral words that were presented on the top or bottom of the screen) to further test this implicit association, but found that the categorization of the words was largely influenced by the ‘moral-up’ association, except for individuals who were careless about morality. By contrast, also using a spaceStroop task, but replacing the experimental words with moral personality words, Hill and Lapsley [14] only found a facilitating effect when immoral personality words were presented at the bottom rather than at the top. They then DOI: 10.1097/WNR.0000000000000528
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showed that metaphors on the vertical dimension represent moral personality, with particular bias toward immoral traits. The studies above suggest that the metaphorical associations of ‘moral-up’ and ‘immoral-down’ are not functionally equivalent. In fact, some research has found basic asymmetries in the way in which individuals process bipolar metaphors in general. For example, Lakens [15] carried out a meta-analysis of five studies on metaphors for emotion, morality, and power, and found that individuals process + polar stimuli (e.g. positive, moral, up) faster than –polar stimuli (e.g. negative, immoral, down). Other research using eye tracking techniques [16] found that after processing the valence concepts, deviations in participants’ horizontal saccade trajectories along the vertical axis were mainly driven by the ‘positive-up’ (vs. ‘negative-down’) association. These studies suggest a privilege for the + polar association. However, this interpretation does not fit Hill and Lapsley’s [14] result, which showed a bias towards the ‘immoral-down’ rather the than ‘moral-up’ association. In the current study, we hypothesized that if the effects of ‘moral-up’ and ‘immoral-down’ associations are asymmetric, this asymmetry might be reflected in the time course during which these associations influence concept processing. Because + polar dimensions have an intrinsic processing benefit compared with –polar dimensions [17], the ‘moral-up’ association might influence the processing of moral concepts faster and the ‘immoral-down’ association might be more likely to exert its effect during a relatively later period of the process. It is possible that the contradictory findings in previous research on moral metaphors have been because of researchers investigating different parts of this time course. To test these assumptions, two experiments were conducted in a Chinese sample. First, experiment 1 replicated the IAT study of Meier and colleagues [8,9] to examine whether Chinese participants have a similar metaphorical association of ‘morality-verticality’ as westerners have. Then, after investigating this general metaphorical association, experiment 2 used eventrelated potential (ERP) techniques and a modified cuetarget task to examine the respective effects of ‘moral-up’ and ‘immoral-down’ associations on the processing of moral words. By recording the electroencephalogram (EEG) signals when participants were processing moral words under the influence of these associations, the time course of the two associations’ effects could be observed and the symmetry of these effects could be investigated.
Experiment 1 As in the study by Meier and colleagues [8,9], participants in experiment 1 were required to complete a similar IAT [18], in this case in terms of morality and vertical space. This task involved categorizing both moral
words and vertical cues (a cue ‘***’ appearing either above or below the screen center) using the same buttons. Methods Participants
Participants included a total of 24 Chinese students (13 women), between 18 and 22 years of age (mean = 20, SD = 1). All participants provided written informed consent to participate in the study. Stimuli
Words: We selected several Chinese words with a moral or an immoral meaning to build a rating scale (words with explicit vertical denotations were excluded, e.g. 高尚 ‘nobility’, which contains a morpheme denoting ‘high’ on the vertical dimension, and 低贱 ‘dastardly’, which incorporates a morpheme denoting ‘low’ on the vertical dimension). Fifty college students (not included in either experiment) rated the extent to which each word had a moral or an immoral meaning (4 = extremely moral; − 4 = extremely immoral). Finally, 80 Chinese moral words and 80 Chinese immoral words were selected as the experimental words (moral valence: morality, mean = 2.60, SD = 1.28; immorality, mean = − 2.70, SD = 1.28). Forty moral words and 40 immoral words selected from these 160 words constituted the materials in the IAT (moral valence: morality, mean = 2.54, SD = 0.36; immorality, mean = − 2.61, SD = 0.41). During the IAT experiment, each word was presented at the center of the screen. Vertical cues
A cue (represented by three asterisks: ***) appeared above or below the center of a 19-inch computer screen at 75 and 25% of the screen height, respectively. The text was white in 64-point arial font. Procedure
The stimuli were presented using the E-Prime software package (Psychology Software Tools Inc., Sharpsburg, Pennsylvania, USA). Participants were asked to categorize items quickly and accurately. Category names (moral, immoral, up, down) appeared on the upper left and right of the screen in white, 18-point, Song typeface. Participants were instructed to press the ‘F’ key if the word or the cue belonged to the category on the upper left of the screen and to press the ‘J’ key if the word or the cue belonged to the category on the upper right. The words and cues remained on the screen until the participants responded. The experiment included several practice trials that contained a 500 ms attention screen (a fixation cross in the center) at the beginning and a 500 ms feedback screen indicating accuracy at the end. However, the main area of interest pertained to the two IAT blocks. One IAT block (Step 3 in Fig. 1) consisted of 40 trials for the compatible categories, where ‘moral’ and ‘up’
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Moral-up first, immoral-down last Wang et al. 249
Fig. 1
Step 1: Initial target concept discrimination (moral words) Moral
Immoral Step 2: Associated attribute discrimination (vertical cues) Up
Down ∗∗∗ Step 3 (IAT1): Compatible combined task Immoral Moral or or down up Moral word Step 4: Reversed target concept or discrimination (moral words) Vertical cue Immoral
Moral Step 5 (IAT2): Incompatible combined task Immoral or up
Moral or down
Moral word or Vertical cue
Procedure for experiment 1 (IAT), which was divided into five steps. To counterbalance the order of the two IAT blocks between participants, half of the participants used the step order of 1,2,3,4,5, whereas half of the participants used the order of 4,2,5,1,3.
categorization shared the same key and ‘immoral’ and ‘down’ categorization shared the same key. The other IAT block (Step 5 in Fig. 1) consisted of 40 trials for the categories combined in reverse, where ‘moral’ and ‘down’ categorization shared the same key and ‘immoral’ and ‘up’ categorization shared the same key. Thus, if in the minds of participants there is a metaphorical association between morality and vertical space, then this association could help combine moral words and vertical cues (i.e. pressing the same key for these two categorizations) in one of the IAT blocks, while interfering with the other. Eventually, different reaction times could be observed between these two IAT blocks. Both IAT blocks contained only a 500 ms attention screen at the beginning. The presentation of these blocks was counter-balanced between participants. The procedure for experiment 1 is shown in Fig. 1. Results
To compare with the research by Meier and colleagues [8,9], we followed the same data-reduction procedure [18], which involved deletion of the first two trials, replacement of trials with response times that were below 300 ms and above 3000 ms with these values (0.5% of trials), deletion of inaccurate trials (1.6% of trials), and a
log transformation of the raw latencies. These transformed data were analyzed, but we reported the means in raw milliseconds for ease of interpretation. Pairedsamples t-tests were used to determine whether participants’ RT on the compatible categories was faster than that on the reverse categories. The results showed that participants classified items faster when the key pressed to respond with the moral words was the same as that used to respond with the up cues and immoral words with down cues (step 3: mean = 584 ms, SD = 83 ms) rather than when these combinations were reversed (step 5: mean = 702 ms, SD = 157 ms), t(23) = − 4.653, P value of less than 0.01, d = − 0.940. Discussion
The results of experiment 1 indicated that implicit associations between morality and vertical space were present in the memory system of the Chinese participants involved in this study. On the whole, the association of moral-up and immoral-down was stronger than that of moral-down and immoral-up. This is consistent with the IAT results found in a western sample reported by Meier and colleagues [8,9]. However, because of the limitation of the traditional IAT paradigm, we could not
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provide a further test of this general association and according to previous research, when subdividing this general metaphorical association, the results became controversial and whether the ‘moral-up’ and ‘immoraldown’ associations have equal effects on moral concepts’ representation has yet to be verified. Therefore, experiment 2 used the ERP technique to separately investigate the ‘moral-up’ and ‘immoral-down’ associations by focusing on the time course of their effects on moral word processing.
Experiment 2 In experiment 2, according to the logic of the IAT, we developed a cue-target task to investigate real-time responses to moral words provided with a certain vertical dimension. In light of the results from experiment 1, we compared two experimental conditions. In the coherent condition, participants were asked to judge the shape of the target at the top of the screen after a moral word was presented at the center of the screen or vice versa (immoral word with the figure at the bottom). Here, the position of the target and the vertical dimension of the moral word were considered compatible. In the conflict condition, participants were asked to judge the shape of the target at the bottom of the screen after processing the center moral word or vice versa (immoral word with the figure at the top). Here, the position of the target and the vertical dimension of the moral word were considered incompatible. In this way, the center word acted as a cue and when participants processed it, at least two kinds of cognitive activities were involved, namely, semantic discrimination and vertical recognition. For example, participants may distinguish the moral attribute of the word and decide on the word and at which position it should be discriminated. Meanwhile, moral metaphors on the vertical dimension may influence this cognitive process. We hypothesized that the processing of the experimental words would be more difficult in the conflict condition than in the coherent condition and that the time courses of the ‘moral-up’ and ‘immoral-down’ associations’ effects would be different. We tested these hypotheses by analyzing participants’ EEG data when they were processing the words. Components to be measured
The first component that we were interested in was the N1 component, a negative potential existing around 100 ms. The distinct N1 shows preparatory activity produced during the primary processing of the stimulus [19] and when a discrimination task is required, the processing of the target stimuli at the attended visual field induces a larger N1 [20,21]. Although this distinct N1 was often observed in an attentional bias field and was used as an index of attentional reinforcement [22], several studies have found that a larger N1 may also be observed when participants are processing the center stimuli under the condition that is conducive to the perceptual
processing [23–25] and this congruous N1 effect may indicate contextual appropriateness as semantic expectations in the congruous condition enhance visual processing and facilitate discrimination of the stimuli [26]. Others also found that a larger N1 could be induced by high than by low predictability words, which suggested that early expectancy/predictability effects could start around 70 ms after exposure to the words [27]. In our experiment, although participants needed to discriminate the shape of the target, the processing of the word (which served as a cue to the target) also involved a discrimination about the moral attribute. Therefore, if ‘moral-up’ and ‘immoral-down’ associations influence this attribute’s discrimination, then expectations of the word’s attributes (including morality and directionality) may be facilitated in the coherent condition, producing enhanced discrimination and a larger N1. The next component that we focused on was the P2, whose latency is around 200 ms and is considered an index of a multidimensional feature detection process [21] and related to high-level perceptual processing [28]. Other researchers believe that the P2 indexes the integration of information about motivation and perception [29]. When the difficulty of the multifeature detection and integration increases, the amplitude of the P2 will be enhanced. Considering that in our experiment, participants should combine moral and directional attributes when processing the words, we predicted that in the coherent condition, because of the compatibility between the word’s attributes and the moral metaphors, the metaphorical associations would make it easier to integrate these two attributes, thus inducing a less positive P2 component. By contrast, these associations would hinder the integration of the word’s attributes in the conflict condition and the difficulty of this process would be increased, which could induce a larger P2. LPC is a late positive-going potential (after 300 ms). Some studies have suggested that LPC is associated with analysis and evaluation [30–32] and some researchers believe that it may reflect conflict-resolution processing [33–35]. The amplitude of LPC is affected by the distribution of mental resources [36]. In the current study, during the late period of word processing, participants needed to prepare to choose the right vertical position at which the target would be presented and this period might involve analysis of the integrated information from the cueing word. Therefore, we supposed that in the conflict condition, this process would be more difficult and participants would need to invest more mental resources to resolve the conflict from the moral metaphors. A larger LPC would then be induced. In conclusion, the time course of moral metaphors’ effects on the representation of the words could be observed by analyzing the three ERP components of N1, P2, and LPC. If the effects of ‘moral-up’ and ‘immoral-
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Moral-up first, immoral-down last Wang et al. 251
down’ associations are asymmetrical, then the ERP results that we hypothesized above may have a different pattern during the processing of the moral and immoral words. Methods Participants
Twenty-six Chinese students were recruited in this experiment; five of them were excluded from data analysis because of excessive artifacts. Finally, 21 participants were included (10 women), between 18 and 24 years of age (mean = 21, SD = 2). Written informed consent was obtained from all the participants before the experiment. This study was approved by The Ethics Committee of Hebei Normal University and the experiments were conducted in compliance with its guidelines. Stimuli
We used the same words as those introduced in experiment 1. Procedure
The experiment adopted a 2 (moral/immoral word) × 2 (up/down hint) within-group design, with stimuli presented using the E-Prime software package. The experiment was divided into ‘coherent’ and ‘conflict’ blocks. Before each block commenced, participants were provided introductory instructions. In the coherent condition, the instructions specified that moral words in the center of the screen indicated that participants should subsequently discriminate the shape of the figure in the box above and that immoral words in the center indicated that they should subsequently discriminate the figure in the box below. In the conflict condition, the instructions specified the reverse (morality-below, immorality-above). Thus, these center words served as metaphorically congruent cues in the coherent condition and metaphorically incongruent cues in the conflict condition. After the instructions and 10 practice trials, the experiment began and the procedure included three steps. First, a fixation cross was presented at the center of the screen for a random duration of 800–1000 ms with two boxes placed at the top and bottom of the screen (placed at 75 and 25% of the screen height, respectively). Second, in the main step of interest, after the fixation cross disappeared, a moral or an immoral word was presented at the center of the screen for a duration of 1000 ms. The EEG signals were analyzed at this step. According to the experimental introduction, the processing of the word should be affected by both the word’s moral attribute and the specific vertical dimension in terms of this attribute. Thus, the effects of ‘moral-up’ and ‘immoral-down’ associations on this process could be investigated by the ERPs induced. In the third step, to ensure that the participants fully processed the word in step 2, the discrimination task was started only after the word disappeared. Two figures (‘□’ and ‘◇’) appeared on
screen, with one randomly chosen to appear in the top box and the other in the bottom box. Participants were required to discriminate whether the figure in the appropriate box was ‘□’ (press ‘F’ button) or ‘◇’ (press ‘J’ button). Thus, to choose the figure in the correct position, participants needed to fully process the previous target word. Participants were required to finish all of the trials in both the coherent and the conflict conditions. Both conditions included the same 80 moral words and 80 immoral words (160 trails), which were ordered randomly. The presentation of these conditions was counterbalanced between participants. The procedure for experiment 2 is shown in Fig. 2. EEG recording and analysis
We recorded EEG from 32 electrode sites (according to the international 10% system) using a Neuroscan system, referenced online to the left mastoid and re-referenced to the average of the left and right mastoids off-line. Bipolar horizontal and vertical electrooculographs were recorded simultaneously to monitor eye movements. Impedance of all electrodes was maintained below 5 kΩ. The sampling rate was 1000 Hz. Data were filtered online with a 0.05–100 Hz band pass and refiltered off-line with a 30 Hz low pass. Ocular artifacts were corrected with an eye movement correction algorithm [37]. ERPs were time locked to the onset of the moral/immoral word in each of the experimental blocks. Epochs ranged from − 100 to 1000 ms after the onset of the stimulus. The 100 ms interval preceding the stimulus onset served as the baseline. A criterion of ± 75 μV was used to reject artifacts (15% of epochs were rejected). ERPs were assessed by mean amplitude measurements in intervals designed to capture various components of interest (such as the N1, P2, and LPC components). Values were subjected to a 2 (moral attribute: moral/immoral) × 2 (vertical dimension: above/ below) × 5 (electrode sites) repeated-measures analysis of variance (ANOVA). We classified these electrode sites into five parts: frontal (F7, F3, Fz, F4, F8); frontal-central (FT7, FC3, FCz, FC4, FT8); central (T7, C3, Cz, C4, T8); central-parietal (TP7, CP3, CPz, CP4, TP8); and parietal (P7, P3, Pz, P4, P8). A Greenhouse–Geisser correction procedure was used when necessary. Results Behavioral results
The trials with response times that were more than 3 SDs from the participant mean and with incorrect responses were excluded from analyses. In total, 5.9% of the data were excluded. A 2 (moral/immoral word) × 2 (top/bottom) repeatedmeasures ANOVA was performed on the reaction time. The interaction between moral attribute and the vertical dimension was significant, F(1,20) = 5.706, P = 0.027, η2 = 0.222. Further tests showed that discrimination to
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252 NeuroReport 2016, Vol 27 No 4
Fig. 2
The preparation before experiment
The preparation before experiment Introduction: morality above, immorality below
Step 1: 800 –1000 ms
Introduction: morality below, immorality above
Step 1: 800 –1000 ms
Step 2: 1000 ms, EEG recording
Step 2: 1000 ms, EEG recording
Step 3: Category judgment
Step 3: Category judgment
Coherent condition
Conflict condition
Procedure for experiment 2. The center word ‘善良’ means goodness and the dotted circle (which is invisible in the experiment) shows the correct target.
the target figure was faster when moral words indicated up (mean = 694 ms, SE = 45) than down (mean = 819 ms, SE = 74), F(1,20) = 6.877, P = 0.016, η2 = 0.256; conversely, discrimination was faster when immoral words indicated down (mean = 724 ms, SE = 50) than up (mean = 841 ms, SE = 77), F(1,20) = 4.413, P = 0.049, η2 = 0.181. Moreover, the main effect of moral attribute was significant, F(1,20) = 4.775, P = 0.041, η2 = 0.193, and discrimination was faster after processing the moral words (mean = 757 ms, SE = 56) than processing the immoral words (mean = 782 ms, SE = 58); the main effect of the vertical dimension was not significant, F(1,20) = 0.123, P = 0.729, η2 = 0.006. These results indicated that after word processing, ‘moral-up’ and ‘immoral-down’ associations still played a role in the figure discrimination task by facilitating the reaction to the figures in metaphorical congruent spatial positions. However, according to the paradigm of the current study, before the discrimination task, participants had processed the words in metaphor congruent and incongruent conditions. Therefore, compared with the figure discrimination, the two metaphorical associations’ effects on word processing were of more interest in the current study and the time course of these effects could be better analyzed using ERP results. ERP results
According to the aim of this research, we analyzed the ERPs with a major focus on the N1, the P2, and the LPC components. A 2 (moral attribute: moral/immoral) × 2 (vertical dimension: above/below) × 5 (electrode sites)
repeated-measures ANOVA was performed, respectively, on the mean amplitude of the N1, whose time window was chosen between 70 and 130 ms after word presentation, the P2, whose time window was chosen between 130 and 300 ms after word presentation, and the LPC, whose time window was chosen between 400 and 700 ms after word presentation. For the N1, the three-way repeated-measures ANOVA showed a significant interaction between moral attribute and the vertical dimension, F(1,20) = 18.151, P < 0.001, η2 = 0.476. Further test showed that the N1 was more negative when the moral words hinted at ‘up’ (mean = − 0.733 μV, SE = 0.280) than when they hinted at ‘down’ (mean = 0.099 μV, SE = 0.245), F(1,20) = 16.310, P = 0.001, η2 = 0.449, whereas although a relatively larger N1 was induced when the immoral words hinted at ‘down’ (mean = − 0.509 μV, SE = 0.217) than at ‘up’ (mean = − 0.307 μV, SE = 0.253), no significant difference was observed, F(1,20) = 1.649, P = 0.214. This pattern of results showed a more distinctive N1 deflection in the coherent condition than in the conflict condition, and this was observed only for the moral words. Moreover, there was a significant main effect of electrode site, F(4,80) = 14.016, P = 0.001, η2 = 0.412, which showed more negative potential at frontal and central areas than parietal areas. For the P2, the three-way repeated-measures ANOVA showed that the interaction between moral attribute and the vertical dimension was significant, F(1,20) = 7.068, P = 0.015, η2 = 0.261. Further test showed that the
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Moral-up first, immoral-down last Wang et al. 253
amplitude of the P2 was higher for the moral words associated with figures at the bottom (mean = 4.863 μV, SE = 0.472) than at the top (mean = 4.066 μV, SE = 0.517), F(1,20) = 15.323, P = 0.001, η2 = 0.434. However, for the immoral words, these amplitudes did not differ significantly (meanup = 4.808 μV, SE = 0.524; meandown = 4.674 μV, SE = 0.462), F(1,20) = 0.263, P = 0.614. These results indicated a more distinctive P2 deflection only for the moral words in the conflict condition. Furthermore, the interaction between moral attribute and electrode site was also significant, F(4,80) = 8.347, P = 0.003, η2 = 0.294. For the LPC, the three-way repeated-measures ANOVA showed a significant interaction among moral attribute, the vertical dimension, and electrode site, F(4,80) = 4.154, P = 0.041, η2 = 0.172. Follow-up analyses showed that for the moral words, when they were associated with figures at the bottom than at the top, the LPC were significantly larger in the frontal area, F(1,20) = 16.623, P = 0.001, η2 = 0.454, and in the frontal-central area, F(1,20) = 8.601, P = 0.008, η2 = 0.301. For the immoral words, when they were associated with figures at the top than at the bottom, the LPC were significantly larger in the frontal-central area, F(1,20) = 5.821, P = 0.026, η2 = 0.225, central area, F(1,20) = 6.127, P = 0.022, η2 = 0.235, and central-parietal area, F(1,20) = 6.851, P = 0.016, η2 = 0.255. To sum up, the above results showed that for both the moral and the immoral words, compared with the coherent condition, a larger LPC was induced in the conflict condition. The grand average ERPs for participants in all blocks are shown in Fig. 3. Discussion
Experiment 2 investigated the time course of the ‘moralup’ and ‘immoral-down’ associations’ effects by analyzing the N1, P2, and LPC components. First, the results for N1 suggested that for the moral words, the coherent condition (moral-up) was consistent with the moral metaphor, which can promote certain expectations about the moral words’ attributions (including semantics and directionality) and can enhance preparatory activity during the primary discrimination of the word. By contrast, in the conflict condition (‘moral-down’), there was a conflict between the experimental instruction and the natural ‘moral-up’ association, and participants’ expectations were interfered with. Preparatory activity was attenuated and participants might need to process the word more completely to make a response. Second, the P2 results suggested that because primary processing of the moral words in the conflict condition was not facilitated, participants need to make more effort to process them. For the moral words, this was first observed in a larger P2 when participants integrated incongruent moral and directional attributes of the word.
However, for the immoral words, neither the N1 nor the P2 was sensitive to metaphor congruency. It is possible that the ‘immoral-down’ association had a delayed effect in later cognitive processing. Third, the LPC results suggested that the difficulty of processing the words in the conflict condition was subsequently reflected on the analysis and evaluation of the word and participants invested more mental resources, which induced a larger LPC. Further statistical analysis showed that this effect was observed both when moral words hinted at ‘down’ and immoral words hinted at ‘up’, and it was more evident at electrode sites posited at frontal-central areas. Some research has suggested that frontal LPC may represent some type of control function [38] and this possibility fits well with a model of evaluative processing [39]. From these perspectives, the findings of the current study suggested that to process both moral and immoral words in the conflict condition, participants needed to inhibit the response tendency created by the metaphor and they thus made more effort to evaluate the word, resulting in increased LPC amplitude. Furthermore, the behavioral results could be seen as the outcome of metaphors’ effect on words processing. Because moral metaphor influenced the process of both the moral and the immoral words, the subsequent discrimination to the figures did not show significant asymmetry: the difference in the reaction time between the coherent and the conflict condition was significant both for moral and for immoral words. Previous ERP research on vertically represented metaphors often used the space-Stroop task and investigated the ERPs induced by spatial targets that were presented after processing abstract concepts [40–42]. However, according to the ERPs results in the current study, metaphor could exert its effect during the period earlier than target discrimination. Moreover, the asymmetry of the metaphor’s effect could be better analyzed by investigating the procedure when processing the bipolar concepts.
General discussion The present study focused on the ‘moral-up’ and ‘immoral-down’ metaphorical associations’ effects on the representation of moral concepts. Using an IAT task, experiment 1 showed a distinct relationship between moral concepts and vertical dimensions, with moral words being associated with ‘up’ and immoral words being between associated with ‘down’. Then, on the basis of this result, experiment 2 used ERP techniques to investigate the time course of the two associations’ effects on word processing. The results showed that the ‘moral-up’ association exerts a long-term effect on moral words’ processing, whereas the ‘immoral-down’ association exerted an
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254 NeuroReport 2016, Vol 27 No 4
Fig. 3
Frontal
Frontal-central
Central-parietal
Parietal
Central
Moral up Moral down −1μv −100 0 1μv
Frontal
Frontal-central
Central-parietal
Parietal
200
400
600
800
1000
800
1000
Time (ms) Central
Immoral up Immoral down −1μv −100 0 1μv
200
400
600
Time (ms)
Grand average ERPs recorded from the frontal (F7, F3, Fz, F4, F8 averaged), frontal-central (FT7, FC3, FCz, FC4, FT8 averaged), central (T7, C3, Cz, C4, T8 averaged), central-parietal (TP7, CP3, CPz, CP4, TP8 averaged), and parietal (P7, P3, Pz, P4, P8 averaged) electrode sites. The time windows of the N1, P2, and LPC are shown, respectively, in light, medium, and dark gray shadings.
effect during a relatively late period in the processing of immoral words. The ‘moral-up’ association first hindered preparatory activity during the primary processing of moral words in the conflict condition and induced a smaller N1. Thereafter, participants invested more effort into the succeeding cognitive activities in this condition, which involved a harder integration of the word’s attributes (morality and directionality) and a larger investment of
mental resources to analyze and resolve the conflict. As a result, higher P2 and frontal LPC amplitudes were observed. By contrast, the effect of the ‘immoral-down’ association was not evident in the N1 and P2 components; this association only induced a larger LPC in the conflict condition when participants processed the immoral word with an ‘up’ instruction. These results indicated an asymmetry in the time courses of the two metaphorical associations’ effect, and the ‘immoral-down’
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Moral-up first, immoral-down last Wang et al. 255
association plays its role later than the ‘moral-up’ association. Moreover, the effects of metaphorical associations extended to the subsequent discrimination task. According to the behavioral results of experiment 2, the ‘moral-up’ association made the discrimination faster to figures at the top than to figures at the bottom, whereas the ‘immoral-down’ association induced a reversed result. Because the metaphor congruency effects had been found on the processing of both moral and immoral words, these behavioral results could be considered the aftereffects of ‘moral-up’ and ‘immoral-down’ associations on word processing. The conceptual models used in previous studies are limited in terms of their ability to interpret metaphor congruency effects in space-Stroop tasks. The automatic association account is useful in that it explains the faster RT in the congruent condition as a function of the automatic association between concepts’ meaning and the vertical position [7,13]. However, this account does not explain the asymmetry of the two opposite poles on a metaphor’s effect. The polarity account provides an alternative explanation of the metaphor congruency effects, stating that this effect is because of a purely structural overlap of + polarity and − polarity codes of the conceptual, perceptual, and response dimensions [15]. Although this viewpoint interprets the asymmetry of the bipolar associations, it refutes the possibility of automatic mapping between the source and the target domains in a metaphor. Nevertheless, the above two conceptual models were partly reflected on the results of the current research, which examined metaphor congruency effects by investigating both overt behavioral results and neural activities during cognitive processing. Notably, although the results of experiment 2 showed asymmetry in the effects of the bipolar associations, this asymmetry should not be attributed to the structural overlap of polarities. This is because in experiment 2, the words to be classified were presented in the center and the vertical manipulation was separate from the word’s location, which makes the overlap in polarities less relevant. Therefore, the results of experiment 2 provide support for the automatic association account. However, these results also suggested that the intention of metaphorical mapping in ‘moral-up’ is closer than ‘immoral-down’, which is similar to the polarity account’s proposal: individuals process + polarities faster than − polarities. Because ‘moral-up’ is an association between two + polar dimensions, the metaphorical mapping in ‘moral-up’ is stronger than ‘immoraldown’ (an association between two polar dimensions). Furthermore, this asymmetry might also be because of the properties of moral concepts. In the relatively safe and harmonious society constructed by modern civilization, moral concepts may be defined as having prosocial
characteristics and the processing of these concepts may be relatively fast and direct. By contrast, immoral concepts are defined as having antisocial characteristics and may elicit criticism. As criticism is a high-level cognitive activity based on the completion of perceptual processing, the associations related to immorality might take effect in a relatively late cognition stage. There are usually two opposite poles of a metaphor (e.g. moral-clean vs. immoral-dirty; powerful-up vs. powerlessdown). Although these bipolar associations are mutually contradictory in semantic meaning, their effects might be asymmetric. According to our results, when thinking about the metaphors’ effects on cognition, we should not only focus on the outcome of these effects but also consider the difference in the time course between their two poles. Reviewing previous research on moral metaphors on a vertical dimension, different experimental materials or paradigms used in different studies might have been sensitive to different parts of this time course, resulting in varying conclusions. The current study makes a contribution toward this issue by documenting the time course of the cognitive processing of moral metaphors on a vertical dimension, which could best be described as ‘moral-up first, immoral-down last’.
Acknowledgements We are grateful to Dr Zachary Estes and Dr Hong Wan for their kind help with this research. This research was supported by National Natural Science Foundation of China (31271111). Conflicts of interest
There are no conflicts of interest.
References 1
Gibbs RW. The poetics of mind: figurative thought, language, and understanding. Cambridge: Cambridge University Press; 1994. 2 Lakoff G, Johnson M. Metaphors we live by. Chicago: University of Chicago Press; 2008. 3 Banerjee P, Chatterjee P, Sinha J. Is it light or dark? Recalling moral behavior changes perception of brightness. Psychol Sci 2012; 23:407–409. 4 Sherman GD, Clore GL. The color of sin white and black are perceptual symbols of moral purity and pollution. Psychol Sci 2009; 20:1019–1025. 5 Zhong C-B, Liljenquist K. Washing away your sins: threatened morality and physical cleansing. Science 2006; 313:1451–1452. 6 Landau MJ, Meier BP, Keefer LA. A metaphor-enriched social cognition. Psychol Bull 2010; 136:1045. 7 Meier BP, Robinson MD, Clore GL. Why good guys wear white. Psychol Sci 2004; 15:82–87. 8 Meier BP, Sellbom M, Wygant DB. Failing to take the moral high ground: psychopathy and the vertical representation of morality. Pers Individ Dif 2007; 43:757–767. 9 Meier BP, Hauser DJ, Robinson MD, Friesen CK, Schjeldahl K. What’s ‘up’ with God? Vertical space as a representation of the divine. J Pers Soc Psychol 2007; 93:699. 10 Stefanucci JK, Storbeck J. Don’t look down: emotional arousal elevates height perception. J Exp Psychol Gen 2009; 138:131–145. 11 Wapner S, Werner H, Krus DM. The effect of success and failure on space localization. J Pers 1957; 25:752–756. 12 Giessner SR, Schubert TW. High in the hierarchy: how vertical location and judgments of leaders’ power are interrelated. Organ Behav Hum Decis Process 2007; 104:30–44.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
256 NeuroReport 2016, Vol 27 No 4
13 14 15
16
17 18
19 20 21 22
23
24 25
26 27
Schubert TW. Your highness: vertical positions as perceptual symbols of power. J Pers Soc Psychol 2005; 89:1–21. Hill PL, Lapsley DK. The ups and downs of the moral personality: why it’s not so black and white. J Res Pers 2009; 43:520–523. Lakens D. Polarity correspondence in metaphor congruency effects: structural overlap predicts categorization times for bipolar concepts presented in vertical space. J Exp Psychol Learn Mem Cogn 2012; 38:726. Gozli DG, Chow A, Chasteen AL. Valence and vertical space: saccade trajectory deviations reveal metaphorical spatial activation. Visual Cognition 2013; 21:628–646. Clark HH. Linguistic processes in deductive reasoning. Psychol Rev 1969; 76:387–404. Greenwald AG, McGhee DE, Schwartz JL. Measuring individual differences in implicit cognition: the implicit association test. J Pers Soc Psychol 1998; 74:1464–1480. Vogel EK, Luck SJ. The visual N1 component as an index of a discrimination process. Psychophysiology 2000; 37:190–203. Luck SJ. Multiple mechanisms of visual-spatial attention: recent evidence from human electrophysiology. Behav Brain Res 1995; 71:113–123. Luck SJ, Hillyard SA. Electrophysiological correlates of feature analysis during visual search. Psychophysiology 1994; 31:291–308. Luck SJ, Hillyard SA, Mouloua M, Woldorff MG, Clark VP, Hawkins HL. Effects of spatial cuing on luminance detectability: psychophysical and electrophysiological evidence for early selection. J Exp Psychol Hum Percept Perform 1994; 20:887. Brang D, Rouw R, Ramachandran VS, Coulson S. Similarly shaped letters evoke similar colors in grapheme–color synesthesia. Neuropsychologia 2011; 49:1355–1358. Sagiv N, Ward J. Crossmodal interactions: lessons from synesthesia. Prog Brain Res 2006; 155:259–271. Sinke C, Neufeld J, Wiswede D, Emrich HM, Bleich S, Münte TF, Szycik GR. N1 enhancement in synesthesia during visual and audio-visual perception in semantic cross-modal conflict situations: an ERP study. Front Hum Neurosci 2014; 8:21. Brang D, Edwards L, Ramachandran VS, Coulson S. Is the sky 2? Contextual priming in grapheme-color synaesthesia. Psychol Sci 2008; 19:421–428. Dambacher M, Rolfs M, Göllner K, Kliegl R, Jacobs AM. Event-related potentials reveal rapid verification of predicted visual input. PLoS One 2009; 4:e5047.
28
29
30
31
32
33 34
35 36 37
38 39
40 41
42
Kranczioch C, Debener S, Engel AK. Event-related potential correlates of the attentional blink phenomenon. Brain Res Cogn Brain Res 2003; 17:177–187. Potts GF, Martin LE, Burton P, Montague PR. When things are better or worse than expected: the medial frontal cortex and the allocation of processing resources. J Cogn Neurosci 2006; 18:1112–1119. Hajcak G, Nieuwenhuis S. Reappraisal modulates the electrocortical response to unpleasant pictures. Cogn Affect Behav Neurosci 2006; 6:291–297. Hajcak G, Moser JS, Simons RF. Attending to affect: appraisal strategies modulate the electrocortical response to arousing pictures. Emotion 2006; 6:517. Ito TA, Larsen JT, Smith NK, Cacioppo JT. Negative information weighs more heavily on the brain: the negativity bias in evaluative categorizations. J Pers Soc Psychol 1998; 75:887–900. Chen S, Melara RD. Sequential effects in the Simon task: conflict adaptation or feature integration? Brain Res 2009; 1297:89–100. Larson MJ, Kaufman DA, Perlstein WM. Neural time course of conflict adaptation effects on the Stroop task. Neuropsychologia 2009; 47:663–670. West R. Neural correlates of cognitive control and conflict detection in the Stroop and digit-location tasks. Neuropsychologia 2003; 41:1122–1135. Olofsson JK, Nordin S, Sequeira H, Polich J. Affective picture processing: an integrative review of ERP findings. Biol Psychol 2008; 77:247–265. Semlitsch HV, Anderer P, Schuster P, Presslich O. A solution for reliable and valid reduction of ocular artifacts applied to the P300 ERP. Psychophysiology 1986; 23:695–703. Johnson R. Event-related potential insights into the neurobiology of memory systems. Handbook Neuropsychol 1995; 10:135. Cunningham WA, Espinet SD, DeYoung CG, Zelazo PD. Attitudes to the right-and left: frontal ERP asymmetries associated with stimulus valence and processing goals. NeuroImage 2005; 28:827–834. Xie J, Wang R, Chang S. The mechanism of valence-space metaphors: ERP evidence for affective word processing. PLoS One 2014; 9:e99479. Zanolie K, Dantzig SV, Boot I, Wijnen J, Schubert TW, Giessner SR, Pecher D. Mighty metaphors: behavioral and ERP evidence that power shifts attention on a vertical dimension. Brain Cogn 2012; 78:50–58. Zhang E, Luo J, Zhang J, Wang Y, Zhong J, Li Q. Neural mechanisms of shifts of spatial attention induced by object words with spatial associations: an ERP study. Exp Brain Res 2013; 227:199–209.
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Moral-up first, immoral-down last: the time course of moral metaphors on a vertical dimension Han Lin Wanga,b, Ya Qiao Luc and Zhong Yi Lua Many abstract bipolar concepts are usually represented by metaphors on vertical dimensions (e.g. positive-up, negative-down). However, several studies have found an asymmetry in the way in which individuals process bipolar dimensions, with + polarities being stronger than − polarities. The current research focused on moral metaphors on a vertical dimension (e.g. moral-up and immoral-down) and examined the asymmetric representation of moral and immoral concepts. The first experiment showed a distinct metaphorical association between morality and vertical space, consistent with earlier research. The second experiment showed that moral and immoral words are processed differently depending on whether they are used as metaphorically congruent or incongruent vertical cues. ‘Moral-up’ association modulated the amplitudes of the N1, P2, and late positive-going potential during the processing of moral words, whereas the ‘immoral-down’ association only modulated the amplitudes of the late positive-going potential induced during the
Introduction Morality, as an abstract social concept, might not be as easily understood or represented as concrete concepts might be, and it appears to be cognitively processed in a particular way. The conceptual metaphor theory proposes that an efficient way to represent abstract concepts is by using metaphors [1]. According to this account, metaphors connect abstract concepts (the target domain) to more concrete concepts (the source domain), making the abstract concepts more understandable. Therefore, metaphors are not merely a linguistic phenomenon but also serve a goal of representation [2]. Consistent with this account, there is evidence that morality is represented in metaphors that involve concrete concepts such as brightness, color, and cleanness (e.g. [3–5]). Using these metaphors that are linked to sensation and perception, individuals might better understand complicated moral concepts. Spatial metaphors (for example, those having to do with ‘up’ and ‘down’) have an especially strong influence on concept formation. A growing body of experimental research has shown that metaphors on vertical dimensions influence a wide range of social psychological phenomena and shape how individuals conceptualize multiple aspects of the social world [6]. For example, researchers have found that there are close relations 0959-4965 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.
processing of immoral words. These results suggest that asymmetry in the processing of vertically represented morality metaphors is reflected in the time course of the representation of these bipolar concepts, with the ‘moral-up’ association having an earlier effect than the ‘immoral-down’ association. NeuroReport 27:247–256 Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. NeuroReport 2016, 27:247–256 Keywords: event-related potential, metaphor, moral concept, time course, vertical dimension a
School of Education, Hebei Normal University, Shijiazhuang, bSchool of Psychology, South China Normal University, Guangzhou, People’s Republic of China and cDepartment of Linguistics and Modern Languages, The Chinese University of Hong Kong, Shatin, Hong Kong Correspondence to Zhong Yi Lu, M.Ed., School of Education, Hebei Normal University, 050000 Shijiazhuang, People’s Republic of China Tel: + 86 0311 807 88218; e-mail: [email protected] Received 15 December 2015 accepted 17 December 2015
between positive emotions and upward sides, whereas negative emotions are linked to downward sides [7–11]. Similarly, powerfulness is usually represented at the top, whereas powerlessness is usually represented at the bottom [12,13]. These studies have shown that many abstract social concepts have close connections with spatial information, with one concept connected with ‘up’ and its polar opposite concept connected with ‘down’. Although metaphors that describe ‘up’ and ‘down’ are a common way to represent some abstract bipolar concepts, research on the vertical dimension of moral metaphors is scarce and conclusions are not fully consistent within and across studies. For instance, Meier and colleagues [8,9] found a significant implicit association between morality and the vertical dimension when using the implicit association test (IAT). They then used a space-Stroop task (that is, classifying moral and immoral words that were presented on the top or bottom of the screen) to further test this implicit association, but found that the categorization of the words was largely influenced by the ‘moral-up’ association, except for individuals who were careless about morality. By contrast, also using a spaceStroop task, but replacing the experimental words with moral personality words, Hill and Lapsley [14] only found a facilitating effect when immoral personality words were presented at the bottom rather than at the top. They then DOI: 10.1097/WNR.0000000000000528
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showed that metaphors on the vertical dimension represent moral personality, with particular bias toward immoral traits. The studies above suggest that the metaphorical associations of ‘moral-up’ and ‘immoral-down’ are not functionally equivalent. In fact, some research has found basic asymmetries in the way in which individuals process bipolar metaphors in general. For example, Lakens [15] carried out a meta-analysis of five studies on metaphors for emotion, morality, and power, and found that individuals process + polar stimuli (e.g. positive, moral, up) faster than –polar stimuli (e.g. negative, immoral, down). Other research using eye tracking techniques [16] found that after processing the valence concepts, deviations in participants’ horizontal saccade trajectories along the vertical axis were mainly driven by the ‘positive-up’ (vs. ‘negative-down’) association. These studies suggest a privilege for the + polar association. However, this interpretation does not fit Hill and Lapsley’s [14] result, which showed a bias towards the ‘immoral-down’ rather the than ‘moral-up’ association. In the current study, we hypothesized that if the effects of ‘moral-up’ and ‘immoral-down’ associations are asymmetric, this asymmetry might be reflected in the time course during which these associations influence concept processing. Because + polar dimensions have an intrinsic processing benefit compared with –polar dimensions [17], the ‘moral-up’ association might influence the processing of moral concepts faster and the ‘immoral-down’ association might be more likely to exert its effect during a relatively later period of the process. It is possible that the contradictory findings in previous research on moral metaphors have been because of researchers investigating different parts of this time course. To test these assumptions, two experiments were conducted in a Chinese sample. First, experiment 1 replicated the IAT study of Meier and colleagues [8,9] to examine whether Chinese participants have a similar metaphorical association of ‘morality-verticality’ as westerners have. Then, after investigating this general metaphorical association, experiment 2 used eventrelated potential (ERP) techniques and a modified cuetarget task to examine the respective effects of ‘moral-up’ and ‘immoral-down’ associations on the processing of moral words. By recording the electroencephalogram (EEG) signals when participants were processing moral words under the influence of these associations, the time course of the two associations’ effects could be observed and the symmetry of these effects could be investigated.
Experiment 1 As in the study by Meier and colleagues [8,9], participants in experiment 1 were required to complete a similar IAT [18], in this case in terms of morality and vertical space. This task involved categorizing both moral
words and vertical cues (a cue ‘***’ appearing either above or below the screen center) using the same buttons. Methods Participants
Participants included a total of 24 Chinese students (13 women), between 18 and 22 years of age (mean = 20, SD = 1). All participants provided written informed consent to participate in the study. Stimuli
Words: We selected several Chinese words with a moral or an immoral meaning to build a rating scale (words with explicit vertical denotations were excluded, e.g. 高尚 ‘nobility’, which contains a morpheme denoting ‘high’ on the vertical dimension, and 低贱 ‘dastardly’, which incorporates a morpheme denoting ‘low’ on the vertical dimension). Fifty college students (not included in either experiment) rated the extent to which each word had a moral or an immoral meaning (4 = extremely moral; − 4 = extremely immoral). Finally, 80 Chinese moral words and 80 Chinese immoral words were selected as the experimental words (moral valence: morality, mean = 2.60, SD = 1.28; immorality, mean = − 2.70, SD = 1.28). Forty moral words and 40 immoral words selected from these 160 words constituted the materials in the IAT (moral valence: morality, mean = 2.54, SD = 0.36; immorality, mean = − 2.61, SD = 0.41). During the IAT experiment, each word was presented at the center of the screen. Vertical cues
A cue (represented by three asterisks: ***) appeared above or below the center of a 19-inch computer screen at 75 and 25% of the screen height, respectively. The text was white in 64-point arial font. Procedure
The stimuli were presented using the E-Prime software package (Psychology Software Tools Inc., Sharpsburg, Pennsylvania, USA). Participants were asked to categorize items quickly and accurately. Category names (moral, immoral, up, down) appeared on the upper left and right of the screen in white, 18-point, Song typeface. Participants were instructed to press the ‘F’ key if the word or the cue belonged to the category on the upper left of the screen and to press the ‘J’ key if the word or the cue belonged to the category on the upper right. The words and cues remained on the screen until the participants responded. The experiment included several practice trials that contained a 500 ms attention screen (a fixation cross in the center) at the beginning and a 500 ms feedback screen indicating accuracy at the end. However, the main area of interest pertained to the two IAT blocks. One IAT block (Step 3 in Fig. 1) consisted of 40 trials for the compatible categories, where ‘moral’ and ‘up’
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Moral-up first, immoral-down last Wang et al. 249
Fig. 1
Step 1: Initial target concept discrimination (moral words) Moral
Immoral Step 2: Associated attribute discrimination (vertical cues) Up
Down ∗∗∗ Step 3 (IAT1): Compatible combined task Immoral Moral or or down up Moral word Step 4: Reversed target concept or discrimination (moral words) Vertical cue Immoral
Moral Step 5 (IAT2): Incompatible combined task Immoral or up
Moral or down
Moral word or Vertical cue
Procedure for experiment 1 (IAT), which was divided into five steps. To counterbalance the order of the two IAT blocks between participants, half of the participants used the step order of 1,2,3,4,5, whereas half of the participants used the order of 4,2,5,1,3.
categorization shared the same key and ‘immoral’ and ‘down’ categorization shared the same key. The other IAT block (Step 5 in Fig. 1) consisted of 40 trials for the categories combined in reverse, where ‘moral’ and ‘down’ categorization shared the same key and ‘immoral’ and ‘up’ categorization shared the same key. Thus, if in the minds of participants there is a metaphorical association between morality and vertical space, then this association could help combine moral words and vertical cues (i.e. pressing the same key for these two categorizations) in one of the IAT blocks, while interfering with the other. Eventually, different reaction times could be observed between these two IAT blocks. Both IAT blocks contained only a 500 ms attention screen at the beginning. The presentation of these blocks was counter-balanced between participants. The procedure for experiment 1 is shown in Fig. 1. Results
To compare with the research by Meier and colleagues [8,9], we followed the same data-reduction procedure [18], which involved deletion of the first two trials, replacement of trials with response times that were below 300 ms and above 3000 ms with these values (0.5% of trials), deletion of inaccurate trials (1.6% of trials), and a
log transformation of the raw latencies. These transformed data were analyzed, but we reported the means in raw milliseconds for ease of interpretation. Pairedsamples t-tests were used to determine whether participants’ RT on the compatible categories was faster than that on the reverse categories. The results showed that participants classified items faster when the key pressed to respond with the moral words was the same as that used to respond with the up cues and immoral words with down cues (step 3: mean = 584 ms, SD = 83 ms) rather than when these combinations were reversed (step 5: mean = 702 ms, SD = 157 ms), t(23) = − 4.653, P value of less than 0.01, d = − 0.940. Discussion
The results of experiment 1 indicated that implicit associations between morality and vertical space were present in the memory system of the Chinese participants involved in this study. On the whole, the association of moral-up and immoral-down was stronger than that of moral-down and immoral-up. This is consistent with the IAT results found in a western sample reported by Meier and colleagues [8,9]. However, because of the limitation of the traditional IAT paradigm, we could not
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provide a further test of this general association and according to previous research, when subdividing this general metaphorical association, the results became controversial and whether the ‘moral-up’ and ‘immoraldown’ associations have equal effects on moral concepts’ representation has yet to be verified. Therefore, experiment 2 used the ERP technique to separately investigate the ‘moral-up’ and ‘immoral-down’ associations by focusing on the time course of their effects on moral word processing.
Experiment 2 In experiment 2, according to the logic of the IAT, we developed a cue-target task to investigate real-time responses to moral words provided with a certain vertical dimension. In light of the results from experiment 1, we compared two experimental conditions. In the coherent condition, participants were asked to judge the shape of the target at the top of the screen after a moral word was presented at the center of the screen or vice versa (immoral word with the figure at the bottom). Here, the position of the target and the vertical dimension of the moral word were considered compatible. In the conflict condition, participants were asked to judge the shape of the target at the bottom of the screen after processing the center moral word or vice versa (immoral word with the figure at the top). Here, the position of the target and the vertical dimension of the moral word were considered incompatible. In this way, the center word acted as a cue and when participants processed it, at least two kinds of cognitive activities were involved, namely, semantic discrimination and vertical recognition. For example, participants may distinguish the moral attribute of the word and decide on the word and at which position it should be discriminated. Meanwhile, moral metaphors on the vertical dimension may influence this cognitive process. We hypothesized that the processing of the experimental words would be more difficult in the conflict condition than in the coherent condition and that the time courses of the ‘moral-up’ and ‘immoral-down’ associations’ effects would be different. We tested these hypotheses by analyzing participants’ EEG data when they were processing the words. Components to be measured
The first component that we were interested in was the N1 component, a negative potential existing around 100 ms. The distinct N1 shows preparatory activity produced during the primary processing of the stimulus [19] and when a discrimination task is required, the processing of the target stimuli at the attended visual field induces a larger N1 [20,21]. Although this distinct N1 was often observed in an attentional bias field and was used as an index of attentional reinforcement [22], several studies have found that a larger N1 may also be observed when participants are processing the center stimuli under the condition that is conducive to the perceptual
processing [23–25] and this congruous N1 effect may indicate contextual appropriateness as semantic expectations in the congruous condition enhance visual processing and facilitate discrimination of the stimuli [26]. Others also found that a larger N1 could be induced by high than by low predictability words, which suggested that early expectancy/predictability effects could start around 70 ms after exposure to the words [27]. In our experiment, although participants needed to discriminate the shape of the target, the processing of the word (which served as a cue to the target) also involved a discrimination about the moral attribute. Therefore, if ‘moral-up’ and ‘immoral-down’ associations influence this attribute’s discrimination, then expectations of the word’s attributes (including morality and directionality) may be facilitated in the coherent condition, producing enhanced discrimination and a larger N1. The next component that we focused on was the P2, whose latency is around 200 ms and is considered an index of a multidimensional feature detection process [21] and related to high-level perceptual processing [28]. Other researchers believe that the P2 indexes the integration of information about motivation and perception [29]. When the difficulty of the multifeature detection and integration increases, the amplitude of the P2 will be enhanced. Considering that in our experiment, participants should combine moral and directional attributes when processing the words, we predicted that in the coherent condition, because of the compatibility between the word’s attributes and the moral metaphors, the metaphorical associations would make it easier to integrate these two attributes, thus inducing a less positive P2 component. By contrast, these associations would hinder the integration of the word’s attributes in the conflict condition and the difficulty of this process would be increased, which could induce a larger P2. LPC is a late positive-going potential (after 300 ms). Some studies have suggested that LPC is associated with analysis and evaluation [30–32] and some researchers believe that it may reflect conflict-resolution processing [33–35]. The amplitude of LPC is affected by the distribution of mental resources [36]. In the current study, during the late period of word processing, participants needed to prepare to choose the right vertical position at which the target would be presented and this period might involve analysis of the integrated information from the cueing word. Therefore, we supposed that in the conflict condition, this process would be more difficult and participants would need to invest more mental resources to resolve the conflict from the moral metaphors. A larger LPC would then be induced. In conclusion, the time course of moral metaphors’ effects on the representation of the words could be observed by analyzing the three ERP components of N1, P2, and LPC. If the effects of ‘moral-up’ and ‘immoral-
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Moral-up first, immoral-down last Wang et al. 251
down’ associations are asymmetrical, then the ERP results that we hypothesized above may have a different pattern during the processing of the moral and immoral words. Methods Participants
Twenty-six Chinese students were recruited in this experiment; five of them were excluded from data analysis because of excessive artifacts. Finally, 21 participants were included (10 women), between 18 and 24 years of age (mean = 21, SD = 2). Written informed consent was obtained from all the participants before the experiment. This study was approved by The Ethics Committee of Hebei Normal University and the experiments were conducted in compliance with its guidelines. Stimuli
We used the same words as those introduced in experiment 1. Procedure
The experiment adopted a 2 (moral/immoral word) × 2 (up/down hint) within-group design, with stimuli presented using the E-Prime software package. The experiment was divided into ‘coherent’ and ‘conflict’ blocks. Before each block commenced, participants were provided introductory instructions. In the coherent condition, the instructions specified that moral words in the center of the screen indicated that participants should subsequently discriminate the shape of the figure in the box above and that immoral words in the center indicated that they should subsequently discriminate the figure in the box below. In the conflict condition, the instructions specified the reverse (morality-below, immorality-above). Thus, these center words served as metaphorically congruent cues in the coherent condition and metaphorically incongruent cues in the conflict condition. After the instructions and 10 practice trials, the experiment began and the procedure included three steps. First, a fixation cross was presented at the center of the screen for a random duration of 800–1000 ms with two boxes placed at the top and bottom of the screen (placed at 75 and 25% of the screen height, respectively). Second, in the main step of interest, after the fixation cross disappeared, a moral or an immoral word was presented at the center of the screen for a duration of 1000 ms. The EEG signals were analyzed at this step. According to the experimental introduction, the processing of the word should be affected by both the word’s moral attribute and the specific vertical dimension in terms of this attribute. Thus, the effects of ‘moral-up’ and ‘immoral-down’ associations on this process could be investigated by the ERPs induced. In the third step, to ensure that the participants fully processed the word in step 2, the discrimination task was started only after the word disappeared. Two figures (‘□’ and ‘◇’) appeared on
screen, with one randomly chosen to appear in the top box and the other in the bottom box. Participants were required to discriminate whether the figure in the appropriate box was ‘□’ (press ‘F’ button) or ‘◇’ (press ‘J’ button). Thus, to choose the figure in the correct position, participants needed to fully process the previous target word. Participants were required to finish all of the trials in both the coherent and the conflict conditions. Both conditions included the same 80 moral words and 80 immoral words (160 trails), which were ordered randomly. The presentation of these conditions was counterbalanced between participants. The procedure for experiment 2 is shown in Fig. 2. EEG recording and analysis
We recorded EEG from 32 electrode sites (according to the international 10% system) using a Neuroscan system, referenced online to the left mastoid and re-referenced to the average of the left and right mastoids off-line. Bipolar horizontal and vertical electrooculographs were recorded simultaneously to monitor eye movements. Impedance of all electrodes was maintained below 5 kΩ. The sampling rate was 1000 Hz. Data were filtered online with a 0.05–100 Hz band pass and refiltered off-line with a 30 Hz low pass. Ocular artifacts were corrected with an eye movement correction algorithm [37]. ERPs were time locked to the onset of the moral/immoral word in each of the experimental blocks. Epochs ranged from − 100 to 1000 ms after the onset of the stimulus. The 100 ms interval preceding the stimulus onset served as the baseline. A criterion of ± 75 μV was used to reject artifacts (15% of epochs were rejected). ERPs were assessed by mean amplitude measurements in intervals designed to capture various components of interest (such as the N1, P2, and LPC components). Values were subjected to a 2 (moral attribute: moral/immoral) × 2 (vertical dimension: above/ below) × 5 (electrode sites) repeated-measures analysis of variance (ANOVA). We classified these electrode sites into five parts: frontal (F7, F3, Fz, F4, F8); frontal-central (FT7, FC3, FCz, FC4, FT8); central (T7, C3, Cz, C4, T8); central-parietal (TP7, CP3, CPz, CP4, TP8); and parietal (P7, P3, Pz, P4, P8). A Greenhouse–Geisser correction procedure was used when necessary. Results Behavioral results
The trials with response times that were more than 3 SDs from the participant mean and with incorrect responses were excluded from analyses. In total, 5.9% of the data were excluded. A 2 (moral/immoral word) × 2 (top/bottom) repeatedmeasures ANOVA was performed on the reaction time. The interaction between moral attribute and the vertical dimension was significant, F(1,20) = 5.706, P = 0.027, η2 = 0.222. Further tests showed that discrimination to
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252 NeuroReport 2016, Vol 27 No 4
Fig. 2
The preparation before experiment
The preparation before experiment Introduction: morality above, immorality below
Step 1: 800 –1000 ms
Introduction: morality below, immorality above
Step 1: 800 –1000 ms
Step 2: 1000 ms, EEG recording
Step 2: 1000 ms, EEG recording
Step 3: Category judgment
Step 3: Category judgment
Coherent condition
Conflict condition
Procedure for experiment 2. The center word ‘善良’ means goodness and the dotted circle (which is invisible in the experiment) shows the correct target.
the target figure was faster when moral words indicated up (mean = 694 ms, SE = 45) than down (mean = 819 ms, SE = 74), F(1,20) = 6.877, P = 0.016, η2 = 0.256; conversely, discrimination was faster when immoral words indicated down (mean = 724 ms, SE = 50) than up (mean = 841 ms, SE = 77), F(1,20) = 4.413, P = 0.049, η2 = 0.181. Moreover, the main effect of moral attribute was significant, F(1,20) = 4.775, P = 0.041, η2 = 0.193, and discrimination was faster after processing the moral words (mean = 757 ms, SE = 56) than processing the immoral words (mean = 782 ms, SE = 58); the main effect of the vertical dimension was not significant, F(1,20) = 0.123, P = 0.729, η2 = 0.006. These results indicated that after word processing, ‘moral-up’ and ‘immoral-down’ associations still played a role in the figure discrimination task by facilitating the reaction to the figures in metaphorical congruent spatial positions. However, according to the paradigm of the current study, before the discrimination task, participants had processed the words in metaphor congruent and incongruent conditions. Therefore, compared with the figure discrimination, the two metaphorical associations’ effects on word processing were of more interest in the current study and the time course of these effects could be better analyzed using ERP results. ERP results
According to the aim of this research, we analyzed the ERPs with a major focus on the N1, the P2, and the LPC components. A 2 (moral attribute: moral/immoral) × 2 (vertical dimension: above/below) × 5 (electrode sites)
repeated-measures ANOVA was performed, respectively, on the mean amplitude of the N1, whose time window was chosen between 70 and 130 ms after word presentation, the P2, whose time window was chosen between 130 and 300 ms after word presentation, and the LPC, whose time window was chosen between 400 and 700 ms after word presentation. For the N1, the three-way repeated-measures ANOVA showed a significant interaction between moral attribute and the vertical dimension, F(1,20) = 18.151, P < 0.001, η2 = 0.476. Further test showed that the N1 was more negative when the moral words hinted at ‘up’ (mean = − 0.733 μV, SE = 0.280) than when they hinted at ‘down’ (mean = 0.099 μV, SE = 0.245), F(1,20) = 16.310, P = 0.001, η2 = 0.449, whereas although a relatively larger N1 was induced when the immoral words hinted at ‘down’ (mean = − 0.509 μV, SE = 0.217) than at ‘up’ (mean = − 0.307 μV, SE = 0.253), no significant difference was observed, F(1,20) = 1.649, P = 0.214. This pattern of results showed a more distinctive N1 deflection in the coherent condition than in the conflict condition, and this was observed only for the moral words. Moreover, there was a significant main effect of electrode site, F(4,80) = 14.016, P = 0.001, η2 = 0.412, which showed more negative potential at frontal and central areas than parietal areas. For the P2, the three-way repeated-measures ANOVA showed that the interaction between moral attribute and the vertical dimension was significant, F(1,20) = 7.068, P = 0.015, η2 = 0.261. Further test showed that the
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Moral-up first, immoral-down last Wang et al. 253
amplitude of the P2 was higher for the moral words associated with figures at the bottom (mean = 4.863 μV, SE = 0.472) than at the top (mean = 4.066 μV, SE = 0.517), F(1,20) = 15.323, P = 0.001, η2 = 0.434. However, for the immoral words, these amplitudes did not differ significantly (meanup = 4.808 μV, SE = 0.524; meandown = 4.674 μV, SE = 0.462), F(1,20) = 0.263, P = 0.614. These results indicated a more distinctive P2 deflection only for the moral words in the conflict condition. Furthermore, the interaction between moral attribute and electrode site was also significant, F(4,80) = 8.347, P = 0.003, η2 = 0.294. For the LPC, the three-way repeated-measures ANOVA showed a significant interaction among moral attribute, the vertical dimension, and electrode site, F(4,80) = 4.154, P = 0.041, η2 = 0.172. Follow-up analyses showed that for the moral words, when they were associated with figures at the bottom than at the top, the LPC were significantly larger in the frontal area, F(1,20) = 16.623, P = 0.001, η2 = 0.454, and in the frontal-central area, F(1,20) = 8.601, P = 0.008, η2 = 0.301. For the immoral words, when they were associated with figures at the top than at the bottom, the LPC were significantly larger in the frontal-central area, F(1,20) = 5.821, P = 0.026, η2 = 0.225, central area, F(1,20) = 6.127, P = 0.022, η2 = 0.235, and central-parietal area, F(1,20) = 6.851, P = 0.016, η2 = 0.255. To sum up, the above results showed that for both the moral and the immoral words, compared with the coherent condition, a larger LPC was induced in the conflict condition. The grand average ERPs for participants in all blocks are shown in Fig. 3. Discussion
Experiment 2 investigated the time course of the ‘moralup’ and ‘immoral-down’ associations’ effects by analyzing the N1, P2, and LPC components. First, the results for N1 suggested that for the moral words, the coherent condition (moral-up) was consistent with the moral metaphor, which can promote certain expectations about the moral words’ attributions (including semantics and directionality) and can enhance preparatory activity during the primary discrimination of the word. By contrast, in the conflict condition (‘moral-down’), there was a conflict between the experimental instruction and the natural ‘moral-up’ association, and participants’ expectations were interfered with. Preparatory activity was attenuated and participants might need to process the word more completely to make a response. Second, the P2 results suggested that because primary processing of the moral words in the conflict condition was not facilitated, participants need to make more effort to process them. For the moral words, this was first observed in a larger P2 when participants integrated incongruent moral and directional attributes of the word.
However, for the immoral words, neither the N1 nor the P2 was sensitive to metaphor congruency. It is possible that the ‘immoral-down’ association had a delayed effect in later cognitive processing. Third, the LPC results suggested that the difficulty of processing the words in the conflict condition was subsequently reflected on the analysis and evaluation of the word and participants invested more mental resources, which induced a larger LPC. Further statistical analysis showed that this effect was observed both when moral words hinted at ‘down’ and immoral words hinted at ‘up’, and it was more evident at electrode sites posited at frontal-central areas. Some research has suggested that frontal LPC may represent some type of control function [38] and this possibility fits well with a model of evaluative processing [39]. From these perspectives, the findings of the current study suggested that to process both moral and immoral words in the conflict condition, participants needed to inhibit the response tendency created by the metaphor and they thus made more effort to evaluate the word, resulting in increased LPC amplitude. Furthermore, the behavioral results could be seen as the outcome of metaphors’ effect on words processing. Because moral metaphor influenced the process of both the moral and the immoral words, the subsequent discrimination to the figures did not show significant asymmetry: the difference in the reaction time between the coherent and the conflict condition was significant both for moral and for immoral words. Previous ERP research on vertically represented metaphors often used the space-Stroop task and investigated the ERPs induced by spatial targets that were presented after processing abstract concepts [40–42]. However, according to the ERPs results in the current study, metaphor could exert its effect during the period earlier than target discrimination. Moreover, the asymmetry of the metaphor’s effect could be better analyzed by investigating the procedure when processing the bipolar concepts.
General discussion The present study focused on the ‘moral-up’ and ‘immoral-down’ metaphorical associations’ effects on the representation of moral concepts. Using an IAT task, experiment 1 showed a distinct relationship between moral concepts and vertical dimensions, with moral words being associated with ‘up’ and immoral words being between associated with ‘down’. Then, on the basis of this result, experiment 2 used ERP techniques to investigate the time course of the two associations’ effects on word processing. The results showed that the ‘moral-up’ association exerts a long-term effect on moral words’ processing, whereas the ‘immoral-down’ association exerted an
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254 NeuroReport 2016, Vol 27 No 4
Fig. 3
Frontal
Frontal-central
Central-parietal
Parietal
Central
Moral up Moral down −1μv −100 0 1μv
Frontal
Frontal-central
Central-parietal
Parietal
200
400
600
800
1000
800
1000
Time (ms) Central
Immoral up Immoral down −1μv −100 0 1μv
200
400
600
Time (ms)
Grand average ERPs recorded from the frontal (F7, F3, Fz, F4, F8 averaged), frontal-central (FT7, FC3, FCz, FC4, FT8 averaged), central (T7, C3, Cz, C4, T8 averaged), central-parietal (TP7, CP3, CPz, CP4, TP8 averaged), and parietal (P7, P3, Pz, P4, P8 averaged) electrode sites. The time windows of the N1, P2, and LPC are shown, respectively, in light, medium, and dark gray shadings.
effect during a relatively late period in the processing of immoral words. The ‘moral-up’ association first hindered preparatory activity during the primary processing of moral words in the conflict condition and induced a smaller N1. Thereafter, participants invested more effort into the succeeding cognitive activities in this condition, which involved a harder integration of the word’s attributes (morality and directionality) and a larger investment of
mental resources to analyze and resolve the conflict. As a result, higher P2 and frontal LPC amplitudes were observed. By contrast, the effect of the ‘immoral-down’ association was not evident in the N1 and P2 components; this association only induced a larger LPC in the conflict condition when participants processed the immoral word with an ‘up’ instruction. These results indicated an asymmetry in the time courses of the two metaphorical associations’ effect, and the ‘immoral-down’
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Moral-up first, immoral-down last Wang et al. 255
association plays its role later than the ‘moral-up’ association. Moreover, the effects of metaphorical associations extended to the subsequent discrimination task. According to the behavioral results of experiment 2, the ‘moral-up’ association made the discrimination faster to figures at the top than to figures at the bottom, whereas the ‘immoral-down’ association induced a reversed result. Because the metaphor congruency effects had been found on the processing of both moral and immoral words, these behavioral results could be considered the aftereffects of ‘moral-up’ and ‘immoral-down’ associations on word processing. The conceptual models used in previous studies are limited in terms of their ability to interpret metaphor congruency effects in space-Stroop tasks. The automatic association account is useful in that it explains the faster RT in the congruent condition as a function of the automatic association between concepts’ meaning and the vertical position [7,13]. However, this account does not explain the asymmetry of the two opposite poles on a metaphor’s effect. The polarity account provides an alternative explanation of the metaphor congruency effects, stating that this effect is because of a purely structural overlap of + polarity and − polarity codes of the conceptual, perceptual, and response dimensions [15]. Although this viewpoint interprets the asymmetry of the bipolar associations, it refutes the possibility of automatic mapping between the source and the target domains in a metaphor. Nevertheless, the above two conceptual models were partly reflected on the results of the current research, which examined metaphor congruency effects by investigating both overt behavioral results and neural activities during cognitive processing. Notably, although the results of experiment 2 showed asymmetry in the effects of the bipolar associations, this asymmetry should not be attributed to the structural overlap of polarities. This is because in experiment 2, the words to be classified were presented in the center and the vertical manipulation was separate from the word’s location, which makes the overlap in polarities less relevant. Therefore, the results of experiment 2 provide support for the automatic association account. However, these results also suggested that the intention of metaphorical mapping in ‘moral-up’ is closer than ‘immoral-down’, which is similar to the polarity account’s proposal: individuals process + polarities faster than − polarities. Because ‘moral-up’ is an association between two + polar dimensions, the metaphorical mapping in ‘moral-up’ is stronger than ‘immoraldown’ (an association between two polar dimensions). Furthermore, this asymmetry might also be because of the properties of moral concepts. In the relatively safe and harmonious society constructed by modern civilization, moral concepts may be defined as having prosocial
characteristics and the processing of these concepts may be relatively fast and direct. By contrast, immoral concepts are defined as having antisocial characteristics and may elicit criticism. As criticism is a high-level cognitive activity based on the completion of perceptual processing, the associations related to immorality might take effect in a relatively late cognition stage. There are usually two opposite poles of a metaphor (e.g. moral-clean vs. immoral-dirty; powerful-up vs. powerlessdown). Although these bipolar associations are mutually contradictory in semantic meaning, their effects might be asymmetric. According to our results, when thinking about the metaphors’ effects on cognition, we should not only focus on the outcome of these effects but also consider the difference in the time course between their two poles. Reviewing previous research on moral metaphors on a vertical dimension, different experimental materials or paradigms used in different studies might have been sensitive to different parts of this time course, resulting in varying conclusions. The current study makes a contribution toward this issue by documenting the time course of the cognitive processing of moral metaphors on a vertical dimension, which could best be described as ‘moral-up first, immoral-down last’.
Acknowledgements We are grateful to Dr Zachary Estes and Dr Hong Wan for their kind help with this research. This research was supported by National Natural Science Foundation of China (31271111). Conflicts of interest
There are no conflicts of interest.
References 1
Gibbs RW. The poetics of mind: figurative thought, language, and understanding. Cambridge: Cambridge University Press; 1994. 2 Lakoff G, Johnson M. Metaphors we live by. Chicago: University of Chicago Press; 2008. 3 Banerjee P, Chatterjee P, Sinha J. Is it light or dark? Recalling moral behavior changes perception of brightness. Psychol Sci 2012; 23:407–409. 4 Sherman GD, Clore GL. The color of sin white and black are perceptual symbols of moral purity and pollution. Psychol Sci 2009; 20:1019–1025. 5 Zhong C-B, Liljenquist K. Washing away your sins: threatened morality and physical cleansing. Science 2006; 313:1451–1452. 6 Landau MJ, Meier BP, Keefer LA. A metaphor-enriched social cognition. Psychol Bull 2010; 136:1045. 7 Meier BP, Robinson MD, Clore GL. Why good guys wear white. Psychol Sci 2004; 15:82–87. 8 Meier BP, Sellbom M, Wygant DB. Failing to take the moral high ground: psychopathy and the vertical representation of morality. Pers Individ Dif 2007; 43:757–767. 9 Meier BP, Hauser DJ, Robinson MD, Friesen CK, Schjeldahl K. What’s ‘up’ with God? Vertical space as a representation of the divine. J Pers Soc Psychol 2007; 93:699. 10 Stefanucci JK, Storbeck J. Don’t look down: emotional arousal elevates height perception. J Exp Psychol Gen 2009; 138:131–145. 11 Wapner S, Werner H, Krus DM. The effect of success and failure on space localization. J Pers 1957; 25:752–756. 12 Giessner SR, Schubert TW. High in the hierarchy: how vertical location and judgments of leaders’ power are interrelated. Organ Behav Hum Decis Process 2007; 104:30–44.
Copyright r 2016 Wolters Kluwer Health, Inc. All rights reserved.
256 NeuroReport 2016, Vol 27 No 4
13 14 15
16
17 18
19 20 21 22
23
24 25
26 27
Schubert TW. Your highness: vertical positions as perceptual symbols of power. J Pers Soc Psychol 2005; 89:1–21. Hill PL, Lapsley DK. The ups and downs of the moral personality: why it’s not so black and white. J Res Pers 2009; 43:520–523. Lakens D. Polarity correspondence in metaphor congruency effects: structural overlap predicts categorization times for bipolar concepts presented in vertical space. J Exp Psychol Learn Mem Cogn 2012; 38:726. Gozli DG, Chow A, Chasteen AL. Valence and vertical space: saccade trajectory deviations reveal metaphorical spatial activation. Visual Cognition 2013; 21:628–646. Clark HH. Linguistic processes in deductive reasoning. Psychol Rev 1969; 76:387–404. Greenwald AG, McGhee DE, Schwartz JL. Measuring individual differences in implicit cognition: the implicit association test. J Pers Soc Psychol 1998; 74:1464–1480. Vogel EK, Luck SJ. The visual N1 component as an index of a discrimination process. Psychophysiology 2000; 37:190–203. Luck SJ. Multiple mechanisms of visual-spatial attention: recent evidence from human electrophysiology. Behav Brain Res 1995; 71:113–123. Luck SJ, Hillyard SA. Electrophysiological correlates of feature analysis during visual search. Psychophysiology 1994; 31:291–308. Luck SJ, Hillyard SA, Mouloua M, Woldorff MG, Clark VP, Hawkins HL. Effects of spatial cuing on luminance detectability: psychophysical and electrophysiological evidence for early selection. J Exp Psychol Hum Percept Perform 1994; 20:887. Brang D, Rouw R, Ramachandran VS, Coulson S. Similarly shaped letters evoke similar colors in grapheme–color synesthesia. Neuropsychologia 2011; 49:1355–1358. Sagiv N, Ward J. Crossmodal interactions: lessons from synesthesia. Prog Brain Res 2006; 155:259–271. Sinke C, Neufeld J, Wiswede D, Emrich HM, Bleich S, Münte TF, Szycik GR. N1 enhancement in synesthesia during visual and audio-visual perception in semantic cross-modal conflict situations: an ERP study. Front Hum Neurosci 2014; 8:21. Brang D, Edwards L, Ramachandran VS, Coulson S. Is the sky 2? Contextual priming in grapheme-color synaesthesia. Psychol Sci 2008; 19:421–428. Dambacher M, Rolfs M, Göllner K, Kliegl R, Jacobs AM. Event-related potentials reveal rapid verification of predicted visual input. PLoS One 2009; 4:e5047.
28
29
30
31
32
33 34
35 36 37
38 39
40 41
42
Kranczioch C, Debener S, Engel AK. Event-related potential correlates of the attentional blink phenomenon. Brain Res Cogn Brain Res 2003; 17:177–187. Potts GF, Martin LE, Burton P, Montague PR. When things are better or worse than expected: the medial frontal cortex and the allocation of processing resources. J Cogn Neurosci 2006; 18:1112–1119. Hajcak G, Nieuwenhuis S. Reappraisal modulates the electrocortical response to unpleasant pictures. Cogn Affect Behav Neurosci 2006; 6:291–297. Hajcak G, Moser JS, Simons RF. Attending to affect: appraisal strategies modulate the electrocortical response to arousing pictures. Emotion 2006; 6:517. Ito TA, Larsen JT, Smith NK, Cacioppo JT. Negative information weighs more heavily on the brain: the negativity bias in evaluative categorizations. J Pers Soc Psychol 1998; 75:887–900. Chen S, Melara RD. Sequential effects in the Simon task: conflict adaptation or feature integration? Brain Res 2009; 1297:89–100. Larson MJ, Kaufman DA, Perlstein WM. Neural time course of conflict adaptation effects on the Stroop task. Neuropsychologia 2009; 47:663–670. West R. Neural correlates of cognitive control and conflict detection in the Stroop and digit-location tasks. Neuropsychologia 2003; 41:1122–1135. Olofsson JK, Nordin S, Sequeira H, Polich J. Affective picture processing: an integrative review of ERP findings. Biol Psychol 2008; 77:247–265. Semlitsch HV, Anderer P, Schuster P, Presslich O. A solution for reliable and valid reduction of ocular artifacts applied to the P300 ERP. Psychophysiology 1986; 23:695–703. Johnson R. Event-related potential insights into the neurobiology of memory systems. Handbook Neuropsychol 1995; 10:135. Cunningham WA, Espinet SD, DeYoung CG, Zelazo PD. Attitudes to the right-and left: frontal ERP asymmetries associated with stimulus valence and processing goals. NeuroImage 2005; 28:827–834. Xie J, Wang R, Chang S. The mechanism of valence-space metaphors: ERP evidence for affective word processing. PLoS One 2014; 9:e99479. Zanolie K, Dantzig SV, Boot I, Wijnen J, Schubert TW, Giessner SR, Pecher D. Mighty metaphors: behavioral and ERP evidence that power shifts attention on a vertical dimension. Brain Cogn 2012; 78:50–58. Zhang E, Luo J, Zhang J, Wang Y, Zhong J, Li Q. Neural mechanisms of shifts of spatial attention induced by object words with spatial associations: an ERP study. Exp Brain Res 2013; 227:199–209.
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