Perception, 2014, volume 43, pages 589 – 594
doi:10.1068/p7715
SHORT REPORT
Two-dimensional grouping affects perisaccadic perception of depth and synchrony Reiko Aruga1, Hideo Saito1, Hideyuki Ando2, Junji Watanabe3§ 1
Graduate School of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku, Yokohama, Kanagawa 223-8522, Japan; 2 Graduate School of Information Science and Technology, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan; 3 NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, 3-1, Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan; e‑mail: [email protected] Received 8 February 2014, in revised form 27 April 2014, published online 13 June 2014 Abstract. There is considerable evidence that, when visual stimuli are presented around the time of a saccade, spatial and temporal perceptions of them are distorted. However, only a small number of previous studies have addressed the perception of a visual image induced by a saccade eye movement (visual image that is dynamically drawn on the retina during a saccade at the speed of the eye movement). Here we investigated three-dimensional and temporal perceptions of the saccade-induced images and found that perceptual grouping of objects has a significant effect on the perceived depth and timing of the images. Keywords: eye movement, perceptual grouping, saccade, saccadic compression, saccade-based display, subjective contour
1 Background Human observers frequently make eye movements to see surrounding environments with the central sensitive area of the retina. Compensating for a retinal image disrupted by a saccadic eye movement is a remarkable challenge for the human visual system. There is a large body of literature on perceptual distortion in space and time for perisaccadically presented visual stimuli (eg Burr, Ross, Binda, & Morrone, 2010, for a review; Cai, Pouget, Schlag-Rey, & Schlag, 1997; Honda, 1993; Lappe, Awater, & Krekelberg, 2000; Mateeff, 1978; Matin & Pearce, 1965). However, little attention has been paid to the perception of images induced by a saccade [ie an image presented on the retina during a saccade at the speed of the eye movement—hereafter called a saccade-induced image (SiI)]. The perceptual features of the SiI remain poorly understood, although the SiI has been applied for a novel visual display (Watanabe, Maeda, & Ando, 2012) and in the field of visual arts (Bell, Parks, & Post, 1986). Here we examine how the object’s configuration in a SiI affects the perception of the SiI, as investigated for perisaccadic spatial compression of flashed stimuli (Matsumiya & Uchikawa, 2001; Sogo & Osaka, 2005). In this work we performed two psychophysical experiments, in which the proximity and connectivity of objects in the SiI were varied. 2 Method We used a vertically aligned one-dimensional (1‑D) light array to present the SiI. When an observer made a horizontal saccade in front of the array, different line images drawn at different retinal locations were integrated into a perceivable two-dimensional (2‑D) image (SiI) (see figure 1a), while the perceived image appeared to be a simple flickering line during fixation. The shape of the SiI was reversed horizontally when eye movements were performed in the opposite direction. It has been reported that the horizontal size of the SiI was about § Corresponding author.
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R Aruga, H Saito, H Ando, J Watanabe
half of the amplitude of a saccade (Hershberger, 1987; Watanabe, Noritake, Maeda, Tachi, & Nishida, 2005b). In our experiments we asked observers to view the SiI by making saccades (figure 1b) and rate the number of perceived depth planes (DPs) and the magnitude of perceived asynchrony (AS) of the SiI. The observers rated DPs also on a five-point scale (1.0, 1.25, 1.5, 1.75, or 2.0) according to the magnitude of depth perception, and AS by five-point scales [0.0 (simultaneous), 0.25, 0.5, 0.75, or 1.0 (completely different times)]. They were also asked to draw a picture of perceived image.
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Figure 1. [In colour online, see http://dx.doi.org/10.1068/p7715] (a) Schematic drawing of moving light array in retinal space–time coordinates. (b) Spatial arrangement of experimental setup, which consists of one light-emitting diode array and two small lights for inducing eye movements. Schematic drawings of moving light array for (c) Rs, (d) Rxy, (e) Rc, and (f ) Ric in retinal space–time coordinates.
In the first experiment we presented four types of visual stimuli, each of which consisted of four white circles on a black background. Four circles were arranged on the corner of a square in standard rectangular arrangement (Rs; see figure 1c), and one circle at upper right was displaced in the direction parallel (Rx), perpendicular (Ry), or orthogonal (Rxy; see figure 1d) to the saccade. We expected the change in proximity of visual stimuli to affect the perceptual grouping of the upper-right circle and other three circles. Each observer viewed and rated all images once. The visual stimuli were presented in a random order between observers. In the second experiment we examined the effect of connecting the circles on DP and AS perceptions. We presented Rxy, Rc (Rxy with solid line connection; see figure 1e), and Ric (Rxy with illusory line connection; see figure 1f ) with the same procedure as the first experiment.
Perisaccadic perception of depth and synchrony
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3 Results The DP results of the first experiment are shown in figure 2a. A one-way repeated-measures ANOVA revealed that there was a significant difference between stimulus types (F3, 42 = 8.12, p
doi:10.1068/p7715
SHORT REPORT
Two-dimensional grouping affects perisaccadic perception of depth and synchrony Reiko Aruga1, Hideo Saito1, Hideyuki Ando2, Junji Watanabe3§ 1
Graduate School of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kohoku, Yokohama, Kanagawa 223-8522, Japan; 2 Graduate School of Information Science and Technology, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan; 3 NTT Communication Science Laboratories, Nippon Telegraph and Telephone Corporation, 3-1, Morinosato Wakamiya, Atsugi, Kanagawa 243-0198, Japan; e‑mail: [email protected] Received 8 February 2014, in revised form 27 April 2014, published online 13 June 2014 Abstract. There is considerable evidence that, when visual stimuli are presented around the time of a saccade, spatial and temporal perceptions of them are distorted. However, only a small number of previous studies have addressed the perception of a visual image induced by a saccade eye movement (visual image that is dynamically drawn on the retina during a saccade at the speed of the eye movement). Here we investigated three-dimensional and temporal perceptions of the saccade-induced images and found that perceptual grouping of objects has a significant effect on the perceived depth and timing of the images. Keywords: eye movement, perceptual grouping, saccade, saccadic compression, saccade-based display, subjective contour
1 Background Human observers frequently make eye movements to see surrounding environments with the central sensitive area of the retina. Compensating for a retinal image disrupted by a saccadic eye movement is a remarkable challenge for the human visual system. There is a large body of literature on perceptual distortion in space and time for perisaccadically presented visual stimuli (eg Burr, Ross, Binda, & Morrone, 2010, for a review; Cai, Pouget, Schlag-Rey, & Schlag, 1997; Honda, 1993; Lappe, Awater, & Krekelberg, 2000; Mateeff, 1978; Matin & Pearce, 1965). However, little attention has been paid to the perception of images induced by a saccade [ie an image presented on the retina during a saccade at the speed of the eye movement—hereafter called a saccade-induced image (SiI)]. The perceptual features of the SiI remain poorly understood, although the SiI has been applied for a novel visual display (Watanabe, Maeda, & Ando, 2012) and in the field of visual arts (Bell, Parks, & Post, 1986). Here we examine how the object’s configuration in a SiI affects the perception of the SiI, as investigated for perisaccadic spatial compression of flashed stimuli (Matsumiya & Uchikawa, 2001; Sogo & Osaka, 2005). In this work we performed two psychophysical experiments, in which the proximity and connectivity of objects in the SiI were varied. 2 Method We used a vertically aligned one-dimensional (1‑D) light array to present the SiI. When an observer made a horizontal saccade in front of the array, different line images drawn at different retinal locations were integrated into a perceivable two-dimensional (2‑D) image (SiI) (see figure 1a), while the perceived image appeared to be a simple flickering line during fixation. The shape of the SiI was reversed horizontally when eye movements were performed in the opposite direction. It has been reported that the horizontal size of the SiI was about § Corresponding author.
590
R Aruga, H Saito, H Ando, J Watanabe
half of the amplitude of a saccade (Hershberger, 1987; Watanabe, Noritake, Maeda, Tachi, & Nishida, 2005b). In our experiments we asked observers to view the SiI by making saccades (figure 1b) and rate the number of perceived depth planes (DPs) and the magnitude of perceived asynchrony (AS) of the SiI. The observers rated DPs also on a five-point scale (1.0, 1.25, 1.5, 1.75, or 2.0) according to the magnitude of depth perception, and AS by five-point scales [0.0 (simultaneous), 0.25, 0.5, 0.75, or 1.0 (completely different times)]. They were also asked to draw a picture of perceived image.
Ti me
Retinal space
22
(a)
Integrated image
e
Retinal space
Ti m
Ti m
e
4.6 m
(b)
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Ti m
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Figure 1. [In colour online, see http://dx.doi.org/10.1068/p7715] (a) Schematic drawing of moving light array in retinal space–time coordinates. (b) Spatial arrangement of experimental setup, which consists of one light-emitting diode array and two small lights for inducing eye movements. Schematic drawings of moving light array for (c) Rs, (d) Rxy, (e) Rc, and (f ) Ric in retinal space–time coordinates.
In the first experiment we presented four types of visual stimuli, each of which consisted of four white circles on a black background. Four circles were arranged on the corner of a square in standard rectangular arrangement (Rs; see figure 1c), and one circle at upper right was displaced in the direction parallel (Rx), perpendicular (Ry), or orthogonal (Rxy; see figure 1d) to the saccade. We expected the change in proximity of visual stimuli to affect the perceptual grouping of the upper-right circle and other three circles. Each observer viewed and rated all images once. The visual stimuli were presented in a random order between observers. In the second experiment we examined the effect of connecting the circles on DP and AS perceptions. We presented Rxy, Rc (Rxy with solid line connection; see figure 1e), and Ric (Rxy with illusory line connection; see figure 1f ) with the same procedure as the first experiment.
Perisaccadic perception of depth and synchrony
591
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3 Results The DP results of the first experiment are shown in figure 2a. A one-way repeated-measures ANOVA revealed that there was a significant difference between stimulus types (F3, 42 = 8.12, p
