Journal oj Abnormal Psychology 1976, Vol. 85, No. 2, 156-166

Affective Encoding and Consequent Remembering in Schizophrenic Young Adults Rolf A. Peterson University of Illinois at Chicago Circle

Soon D. Koh and Lawrence Kayton Psychosomatic and Psychiatric Institute, Michael Reese Hospital and Medical Center, Chicago, Illinois

In a scries ol" previous studies we repeatedly lound a recall deficit in schizophrenic young adults. The question raised in this study was whether schizophrenics' recall deficit can be ameliorated if appropriate encoding behaviors are experimentally induced. The subjects were 18 schizophrenics, IS nonschizophrenic psychiatric patients, and 19 normals. In the first session the subject was shown SO words on a screen one at a time and rated them in terms of pleasantness-unpleasantness (orienting task) ; an unexpected free recall followed (incidental recall). In the second session, given a week later, the subject was forewarned about the recall test prior to his engagement in the orienting task for another 50-word list; lour free-recall trials followed (intentional recall). The recalls of the three groups were comparable in both sessions. The recall performance was also examined separately for the pleasant and unpleasant words, as rated by the subjects. All three groups tended to recall pleasant words more often than unpleasant words. It was therefore concluded that the schizophrenics' recall and pleasure deficits arc probably remediable by means of attentional and encoding treatments.

When schizophrenic patients arc asked to recall an overloaded word list shown a few moments earlier, they perform poorly (e.g., Bauman, 1971; Levy & Maxwell, 1968; Nachmani & Cohen, 1969). Using nonpsychotic schizophrenic young adults as subjects, Koh and his co-investigators have repeatedly found deficient performance in free-recall tasks. These subjects were consistently poor in remembering an "unrelated" word list (Koh & Kayton, 1974; Koh, Kayton, & Berry, 1973), a categorically related word This study was partly supported by U.S. Public Health Service Grants MH-18991 and MH-5519, State of Illinois Grant 432-13-RD, and the Michael Reese Hospital Research Institute Council. This study is part of a program investigating schizophrenia which is being conducted under the general direction of Roy R. Grinker, Director of the Psychosomatic and Psychiatric Institute, Michael Reese Hospital. We are grateful to Deborah Ebcrhart, Don A. Spivak, and Thomas F. Withcridge for their help in collecting and analyzing the data and drafting this report. Requests for reprints should be sent to Soon D. Koh, Psychosomatic and Psychiatric Institute, Michael Reese Hospital, 29th and Ellis Avenue, Chicago, Illinois 60616.

list (Koh, Kayton, & Berry, 1973), an affect-laden word list (Kayton & Koh, 1975), and anomalous (grammatical but meaningless) and normal sentences (Koh, Kayton, & Schwarz, Note 1). These studies also presented evidence that the recall deficit is at least in part attributable to the inefficiency of schizophrenics in utilizing the semantic, syntactic, and affective features experimentally provided for their mnemonic encoding and organization and in inventing their own idiosyncratic mnemonic strategies. In the free-recall paradigm used in these studies, however, the mnemonic strategies adopted by the subject are left at his own option. Accordingly, it is not clear whether the schizophrenic recall deficit so consistently observed is due to some permanent, built-in incapacity unique to schizophrenia or simply clue to a lack of conscious effort by the subject to elaborate the to-be-remembered words. Recently, it has become increasingly clear that the encoding process taking place during the input stage is crucial for remembering (Craik & Lockhart, 1972; Melton & Martin, 1972; Tulving & Thomson, 1973). In

156

ENCODING AND REMEMBERING BY SCHIZOPHRENICS

the present study, therefore, the subject's selective attention and mnemonic strategy during the acquisition stage were placed under experimental control, using the incidental learning paradigm, and the effect of encodingresponses on the subsequent recall was examined. In the typical incidental learning paradigm the subject is not instructed to learn but is required to engage in an orienting task to ensure that he pays attention to and encodes the input materials in the manner determined by the experimenter; an unexpected recall test follows. This procedure, therefore, permits the experimenter to manipulate the subject's control processes at the input stage through a systematic variation of the orienting task. It has been well documented that an orienting task requiring semantic encoding produces a level of recall equivalent to that resulting from the intentional learning procedure in which the subject is forewarned about the recall test (see Jenkins, 1974). That is, the semantic encoding, rather than the intention to memorize per se, is critical for remembering. Apparently, people ordinarily pay attention to and encode input items according to semantic attributes when they are instructed to learn the materials for a subsequent recall test. The semantic orienting tasks used most often include rating the input words according to their pleasantness or unpleasantness, rating the frequency of usage of the words, and semantic classification of the words. The subjects in this experiment participated in two sessions, incidental learning and intentional learning. In the first session the orienting task consisted of (a) writing down each of SO words which appeared on a screen one at a time, and (b) rating each word in terms of a 7-point pleasantness scale. Thus, the subject's attention and affective-semantic encoding of the words were assured. Following this, an unexpected free-recall test was given. In the second session, which followed approximately 1 week later, the subject was instructed to write down and rate another 50-word list, as in the first session, but was told at the outset that there would be a subsequent recall test. A repeated free-recall test followed, in which the word list was shown

157

three more times. That is, both the encoding and the intention to learn were experimentally induced in this session. The subjects who participated in the present experiment were comparable to those in the studies by Koh and his co-investigators cited above because they were drawn from the same subject pool and selected and diagnosed by the same clinical team, using the same procedure. Accordingly, this study took the schizophrenic recall deficit repeatedly found in the above studies as its reference point in assessing the influence of the orienting task on schizophrenic remembering. The major questions addressed were: (a) whether the recall deficit of schizophrenic young adults found in the free-recall task disappears when the affective-semantic encoding is explicitly induced; (b) whether schizophrenics' recall of affective words differs from those of normals and nonschizophrenic patients, due to their disturbances in affect; (c) whether schizophrenics' rate of recall learning becomes comparable to those of the other two groups when appropriate encoding is initially achieved; and (d) whether schizophrenics use the affective features of words for their mnemonic organization. METHOD Subjects The subjects were 18 schizophrenics, 15 nonschizophrenic psychiatric patients, and 19 college students. Table 1 describes the demographic characteristics of the subjects. The three groups were similar in age and years in school. The two patient groups, furthermore, were comparable in vocabulary as assessed by the Wechsler Adult Intelligence Scale (WAIS) vocabulary test, in length of psychiatric hospitalizalion, and in phcnolhiazinc medication. The vocabulary level of the college students, though not directly measured, was probably as high as that of the patients. The students were attending the University of Illinois at Chicago Circle; a comparable group from that university, who participated in a previous study (Koh & Peterson, 1974), showed mean WAIS scaled vocabulary scores of 14.0. All subjects were born in the United States and were Caucasians. The socioeconomic status of the subjects, estimated by the Hollingshead and Redlich (1958) twofactor index, indicated that the patients were predominantly from upper, and the normals were mostly from middle, socioeconomic backgrounds. The patient subjects were selected and diagnosed by a clinical research team. Grinker (1975) and Grinker and Holzman (1973) have detailed the diag-

S. KOH, L. KAYTON, AND R. PETERSON

158

TABLIi I ACTUARIAL ClIARACTElilSTICS OK SlJliJKCTS

Characteristic

Sex Male Female Age M Range Education M Range Vocabulary*

Normal

9 10

Schizophrenic

9 9

5 10

20.6 18-26

22.8 18-27

22.6 18-28

13.7 12 16

13.8 11-17

13.3 11-16

11.8 10- 16

12.2 9-17

M

Range HospitaHzalum1' Mdn. Range Medication" Mdn.'1 Range Social position11 1-2 21% 3 37% 4-5 42%

3.7 .5- 14 300 102-506

61%

28% 11%

3.4 .5-12 200 50-1,350 64%

22% 14%

Note.. Age and education data are given in years, hospitali/ation data are given in months, and medication data in milligrams. * Wcchsler Adult Intelligence Scale vocabulary scale scores; the mean normative score is 10.

h Previous hospitali/ation is included. "Daily dose of phenothiazine medication in terms of chlorpromazine; dose levels of other drugs arc converted by the Cole andl] Davis (1969) table. n — 11 and 5 for ,schi/.ophrenics and nonschizophrenics, respectively. « The Hollingshead Two-Factor Index of Social Position: 1-2, upper; 3, middle; 4-5, lower position.

nostic procedure (sec also Koh, Kayton, & Berry, 1973; Koh, Kayton, & Schwarz, 1974). In brief, all young adults hospitalized at the Psychosomatic and Psychiatric Institute of the Michael Reese Hospital in Chicago who were not in a sustained psychotic state were interviewed by the Director of the Institute (Roy R. Grinker). This interview was tape recorded and reviewed by the clinical research team, which included the second author. The team's consensus on schizophrenic versus nonschizophrenic diagnosis was required for the inclusion of a patient in the present study. Using definitions provided by Grinker and Holzman (1973), the schizophrenics were subclassificd as follows: chronic, 7; schizoaffectivc, 5; paranoid, 3; acute, 2; and others, 2. The subclassifications of the nonschizophrenics were: character disorder, 5; manic-depressive, 3; depression, 3; borderline, 2; and others, 2. Neither the schizophrenics nor the nonschizophrenics revealed sustained psychotic behaviors during the period of the study, and most of them were discharged from the Institute within a few months after their partici-

pation in the experiment. As we conceive it, the term schizophrenia does not necessarily imply psychosis, which is a descriptive term. Since all of the schizophrenic subjects who participated in the present study and in our previous studies were at the postpsychotic recuperation phase during the time of their participation, we call them nonpsychotic schizophrenics. We believe that the nonpsychotic forms of schizophrenia (e.g., schizophrenia in remission, ambulatory schizophrenia, and schizotype) represent the prototype of schizophrenia and that the essence of the schizophrenia syndrome may be found more appropriately in these schizophrenics than in classical, hospitalized schizophrenics who are acutely and chronically psychotic. The normals were paid students from the University of Illinois at Chicago Circle, screened by the Minnesota Multiphasic Personality Inventory (MMPI). Any student whose MMPI T score exceeded 70 on any scale was rejected. The MMPI was also administered to 16 schizophrenics and 13 nonschizophrenics after they completed the two experimental sessions, not as a criterion for selection but rather as an independent description of the, groups. The group MMPI profiles are shown in Figure 1. The Si Scale was not administered to the normal group. The elevation and pattern of the mean schizophrenic profile matched Gilbcrstadt and Duker's (196S) 2-7-8 code type, which is typical of pseudoneurotic or chronic undiffercntiatcd schizophrenia or anxiety reaction or depressive reaction in schizoid personality. The mean MMPI profile of the nonschizophrenic group consisted of a combination of the mildly elevated 2-7-8 code type and the 4 (psychopathic deviate) code type.

Materials The two 50-word lists, designated A and B, were each constructed from various sources of affectively rated words. In a preliminary study SO students from the University of Illinois at Chicago Circle rated these 100 words on a 9-point pleasantnessunpleasantness scale. Table 2 summarizes the mean

o SCHIZ. ( M,7;F,9) a NOMSCHIZ.(M,4;F,9) • NORMAL (M,9;F,IO)

F K

I 2 3 4 5 6 7 8 9 0 Hs D Hy Pd Mf Pa Pt Sc Ma SI

MMPI

BASIC

SCALES

FIOUKK 1. Mean MMPI profiles for three groups. (The Si Scale was not given to the normal group.)

ENCODING AND REMEMBERING BY SCHIZOPHRENICS

159

TABLE 2 PLEASANTNESS RATINGS AND TllORNDlKE-LoKGE G COCNTS FOR TJIE WORDS OF LlSTS A AND Ij

List A Word

M

love embrace affectionate intimate joyful cheerful trust delightful baby ecstatic harmony contented wise woman mother breast exalted genial dessert extra giddy catch graphic product barrel amount temporary distant bland snake dirty despondent mandatory weak defect brooding dreary distressed dejected wretched ridicule anguish mournful shame enemy grieved deceive pain failure hate

8.25 7.80 7.79 7.69 7.49 7.36 7.36 7.31 7.30 7.24 7.20 7.06 7.04 6.97 6.94 6.34 5.98 5.77 5.74 5.44 5.41 5.41 5.30 5.18 5.12 4.96 4.36 4.25 3.62

3.55 3.48 3.42 3.40 3.29 3.21 3.19

3.15 2.94 2.84 2.80 2.72 2.66 2.64 2.62

List B SD

.87 .82 .90 1.04 1.03

.79

G

AA 34 12 24 14 30 AA 32 AA 2 23

1.09 1.16 1.28 1.55 1.20 1.07 1.27 1.23 1.43 1.29 1.73 1.06 1.48

12 AA AA

1.68

32 6 AA

.91

.86 .90 .62 .36 .59 .98

.95 1.08 1.60 .96

1.17 .87 1. 00 .90 .92 .95 .69 1.10 1.01 1.09

1.08

.94

2.59

1.07 1.17

2.58 2.53 2 24 2.17 1.66

1.16 1.20 1.03

.92

.88

AA A (13) 9 12

3 A 32

AA 19 A 4 28 31 1 1 A 14 (26)

14 (38)

4 21 9 12 8 A AA

(31)

33 AA 48 A

Word

M

kiss caress happiness beauty vacation kind lovely jolly friendly comfort successful faithful elated enthusiastic melody rapture perfume agreeable thought buoyant affable geometric hybrid essential cord mammoth scries carry (lat hasty spider dismayed danger dismal woeful bad worried discouraged quarrel

8.07 7.96 7.96 7.79 7.57 7.54 7.46 7.40 7.31 7.26 7.21 7.14 7.10 7.00 6.94 6.78 6.55 6.54 6.31 6.06

ugly

despise hopeless lonely depressed morbid misery 1 error death rejected beating

SD

.92

.73 .98 1.03 1.01

.97 .91 .80 .97 1.23 1.77 1.34 1.43

.97

1.13 1.58 1.56

.99

1.11

.99

G AA 12 A AA 33 AA A 22 A A A

48 1 12 15 10 21

16 AA 5 3 1 5

S.65

1.05

5.34 5.27 5.15 4.97 4.97 4.96 4.86 4.52

1.22

3.89 3.50 3.44

1.20 1.18

.90

(20)

3.21 3.21 3.21 3.16 3.02 2.93 2.85 2.80 2.71 2.54 2.52 2.51 2.47 2.36

1.16 1. 10

AA 13 4 AA (A)

2.35 2.30 2,29 2.7l

.61 1.22

.57

1.25 .89

.74 .71

.75 .92 .94 .87 .97 .91

33 30 3 A AA A 15 24

(23)

.98

A 34 26 17 35 3 3 26

1.37 1.48

48 AA

l.ll

(17)

1.16 1.13 1.20 1.05 1.14

1.33

5

Note, The numbers in parentheses refer to approximations of the G count. ratings and the Thorndike-Lorge frequency (G) counts. The range and form of the pleasantness scale and the G counts between the two lists were found to be comparable. That is, when the mean pleasantness values of the SO words in each list were arranged in rank order so that the words which shared the same rank were treated as identical, the product-moment correlation between the pleasantness

values of Lists A and B was .99, and the regression equation had the intercept of .02 and the slope of 1.02. The G-counl distributions of the A and B lists were, respectively: AA or A counts, 16 and 17 words; 20 to 49 counts, 15 and 14 words; and 1 to 19 counts, 19 and 19 words. The product-moment correlations between the pleasantness ratings and the G counts were positive but slight: List A, r ~ .23,

160

S. KOTT, L. KAYTON, AND R. PETERSON

p > .10; List B, r ~ .18, p > .10. The two lists were therefore judged to be equivalent and interchangeable in the present experiment. Slides were made of each word in black uppercase letters on a gray background. Five copies were made of each slide to facilitate the mullitrial presentation of the list and to vary the presentation order of the words across subjects. The slides were presented on a 40 X 40-crn rear projection screen by a Kodak Carousel projector. The words appeared in the center of a 32.5 X 32.5-cm lit area about 1.5 m from the subject. The presentation and exposure time of each word were regulated by a control panel (Lehigh Valley Electronics Model 1648) and timers.

Procedure Each subject participated in two sessions: the incidental learning session followed by the intentional learning session. The two sessions were separated by approximately 1 week, ranging from 2 to 21 days. The schizophrenics and nonschizophrcnics were tested individually, and the normals participated in groups of 1 to 6 subjects. In the incidental learning (first) session the following instructions, typed on a S X 8-inch card, were given to the subject: In this experiment we would like to find out how people feel about certain words—that is, how "pleasant" or "unpleasant" the words are. You will be shown a list of SO words on the screen in front of you. These words will appealone at a time. Each time you see a word, write it down in the space provided. Then indicate how you feel about the word by placing a check mark in one of the columns next to the word. As you sec, there are seven different columns. Each column stands for one of the following categories: (1) very unpleasant; (2) unpleasant; (3) somewhat unpleasant; (4) neutral; (5) somewhat pleasant; (6) pleasant; (7) very pleasant. Rate each word according to your initial feeling. Ask yourself, "How pleasant or unpleasant is the word?" Please try to be spontaneous. You will rate the entire list of words two times, but the words will appear in a different order the second time. Now read the instructions at the top of the sheet. Do you have any questions? Thus, the orienting task consisted of writing down and then rating each word in the appropriate space on the answer form. This rating was repealed with the same words, but the presentation order was different the second time. The subject was allowed 10 seconds for each word. Approximately half of the subjects in each group were shown List A, and the remaining half were shown List B. The presentation order of the words varied over subjects. After completing the orienting task, the subject was asked to put his/her name on the 3-page answer form, after which the experimenter turned off the projector light, collected the form, and gave the

subject a new answer form for the unexpected free recall. These activities lasted a minimum of 30 seconds, during which time the items in the primary memory store were presumably emptied and rehearsal was largely prevented. The subject was then instructed to write down in any order as many words as could be remembered from the list just rated. The subject was allowed up to 5 minutes for this free-recall task. A cued recall then followed. The answer sheet for this task was divided into seven columns, headed by the seven pleasantnessrating categories (cues) that the subject had used in the orienting task. The subject was instructed to write down as many words as he/she could remember, placing each under the column heading that corresponded to the rating of the word. The subject was given up to S minutes for this task. Finally, a recognition test was given. The answer sheet was composed of SO A-list and 50 B-list words. List A words served as distractor items for subjects who had rated List B and vice versa. The subject was instructed to check the "yes" column if he/she had seen and rated the word or the "no" column if he/she had not. Before ending the first session the experimenter debriefed each subject, explaining that the experiment was designed to find out how much the pleasantness ratings would influence natural, unintentional memory processes and that prior knowledge of the recall task would have contaminated these processes. In the intentional learning (second) session the subject was informed in advance that the session would consist of a series of recall tasks with a 50-word list and that he/she would begin the session by rating each word just once. Subjects who rated List A in the first session were given List B, and subjects who previously rated List B were given List A. After the ratings were completed, the subject received the following instructions for the multitrial free recall: (a) subject would see the 50 words again on the screen for 2 seconds each; (b) a 3-cligit number would appear at the end of the list; (c) subject would first write down that number and then count backwards by 1, writing down each successive number as fast as possible until told to slop; (d) subject would then write down all of the words he/she could remember in any order; (c) this sludy-counling-and-recall task would be repeated three more times. The duration of the backward counting was 30 seconds (rehearsal prevention). The subject was allowed 5 minutes for each free recall. The presentation order of the words varied over trials and subjects. It should be noted that the present design did not include a separate experiment to establish the schizophrenic recall deficit. As we previously mentioned, young schizophrenics comparable to the present subjects have invariably shown a recall deficit in spile of the varying nature of the to-beremembered word lists. We believe that such invariant evidence of a recall deficit based on several independent studies is more powerful and reliable than evidence based on a single-shot study.

ENCODING AND REMEMBERING BY SCHIZOPHRENTCS

RESULTS Pleasantness Rating The pleasantness ratings assigned by subjects in the orienting task constituted an experimentally imposed encoding system. Tf the three groups used markedly different encoding systems, then the consequential recall performance might require different interpretation because it is assumed that remembering is largely a function of encoding behavior. Accordingly, it was necessary to examine the three groups' pleasantness ratings. The ratings of the present groups were first compared with those of the 50 college students shown in Table 2. The product-moment correlations between the mean ratings for Lists A and B were, respectively, .97 and .98 for the schizophrenics; .97 and .98 for the nonschizophrenics; and .99 and .99 for the normals. The correlations among the present three groups on the mean ratings for Lists A and B ranged from .96 to .99. That is, the common variance shared among the three groups ranged from 92% to 97%. The form of the pleasantness scaling produced by each patient group was examined by plotting each group's mean ratings against the normals' mean ratings. The slopes for the two lists were in the vicinity of unity (b — .93 to b = 1.01) with the exception of the schizophrenics for List A (b = .76). That is, for List A the schizophrenics, compared with the normals, tended to assign less pleasant ratings to pleasant words and less unpleasant ratings to unpleasant words. Consequently, for List A (but not List B) the number of words with "unpleasant" and "very unpleasant" as well as "pleasant" and "very pleasant" ratings was smaller in the schizophrenic group. However, if all three pleasant categories and all three unpleasant categories, respectively, were combined, the three groups had approximately the same number of pleasant, unpleasant, and neutral words for each list (see Figure 2). Finally, the discrepancy between the two consecutive ratings of the same 50 words in the first session offers evidence for the internal consistency or reliability of the subjects' judgments. The mean rating-category changes

161

in the schizophrenics, nonschizophrenics, and normals were, respectively, .66 (SI) — .49), .53 (SD = Al), and .30 (SD = 1.3). The differences between the schizophrenics and normals, F(l,35) = 9.58, p < .01, and between the nonschizophrenics and normals, F(l,3l) = 5.39, p < .05, were significant, but the difference between the two patient groups was nonsignificant. In sum, the pleasantness encoding systems of the three groups were generally comparable. It should be noted, however, that the internal consistency of the two patient groups was low and that the schizophrenics' pleasantness scale for List A tended to be constricted in form. Incidental Learning Free recall. The correct recall of the 50 words, which were rated twice in the orienting task, was as follows: schizophrenics, 38.8% (SD - 12.9); nonschizophrenics, 37.9% (SD = 11.5); and normals, 43.7% (SD = 9.2). The group difference was not significant. Figure 2 (left panel; top, left) shows these results. The incidental recall of the three groups is also separately illustrated in Figure 2 (left panel, left) for each affective rating. The 50 words on each list were classified into three categories, based on the respective group mean pleasantness ratings. Pleasant words had mean ratings above 4.5; unpleasant words, below 3.5; and neutral words, 3.5 to 4.5. The number of pleasant, unpleasant, and neutral words on List A were, respectively, 20, 24, and 6 words for the schizophrenics; 20, 23, and 7 words for the nonschizophrenics; and 21, 22, and 7 words for the normals. The numbers of pleasant, unpleasant, and neutral words on List B were, respectively, 22, 21, and 7 words for the schizophrenics; 20, 22, and 8 words for the nonschizophrenics; and 21, 21, and 7 words for the normals. That is, the number of words in each category was approximately the same among the three groups. It was assumed that data analysis based on these combined categories would minimize the effects of the low internal consistency and the constricted scale form found in the patient groups.

162

S. KOH, L. KAYTON, AND R. PETERSON BETWEEN-GROUP

INCIDENTAL

INCIDENTAL

I

INTENTIONAL

1

2 3 TRIAL

4

INTENTIONAL

FIGURE 2. Mean percentage correct recall in incidental and intentional learning sessions. (The recall in the intentional learning [second session I is shown as a function of trials. P, U, and N refer to pleasant, unpleasant, and neutral, respectively, and the numbers in parentheses indicate the mean numbers of pleasant, unpleasant, and neutral words rated by each group, respectively.)

The three groups showed no difference in the recall of pleasant words, unpleasant words, or neutral words. The incidental recall of pleasant, unpleasant, and neutral words within each group is illustrated in Figure 2 (right panel, left). Although all three groups tended to recall the pleasant words more than the unpleasant words (a 1'ollyanna tendency), the within-group comparison was significant in the normals, £(18) =• 4.75, p < .001, and in the nonschizophrenics, £(14) = 4.38, p < .001, but not in the schizophrenics. Cued recall. When the pleasantness categories were provided as retrieval cues, the recall performance was as follows: 36.7% (SD = 14.2) for the schizophrenics, 34.9 (SD — 13.2) for the nonschizophrenics, and 42.3

(SD = 10.6) for the normals. Although the cued recall followed immediately after the free recall, the three groups' performance on the former was slightly but not significantly inferior to their performance on the latter. That is, the affective categories had little value as retrieval cues. The pleasant-word recall was again better than the unpleasantword recall in all three groups, and this difference was significant in all three groups: the schizophrenics, £(17) — 2.54, p < .05; the nonschizophrenics, £(14) = 2.88, p < .02; and the normals, t ( 1 8 ) = 2.59, p < .02. Recognition memory. The mean hit rates, p (old/old), of the schizophrenics, nonschizophrenics, and normals were, respectively, .93, .95, and .96, and the mean false-alarm rates

ENCODING AND REMEMBERING BY SCHIZOPHRENICS

(old/new) were, respectively, .03, .06, and .04. The group differences on both measures were not significant. That is, whereas approximately 90% of the affectively encoded words were still in the memory storage and, therefore, were available, fewer than half of them were accessible in the free and cued recall tasks. Mnemonic organization. If the subject recalled pleasant and unpleasant words in immediate temporal sequence, respectively, then the words must have been organized and stored in memory in accordance with their affective features. Bousfield's (19S3) ratio of repetition was applied to measure this phenomenon. A repetition was defined in the present application as the contiguous recall of two items from the same pleasantness category, based on the appropriate group mean ratings. The three subcategories of pleasant and unpleasant ratings were again collapsed into one pleasant and one unpleasant category. The measure was then a simple ratio of the number of obtained repetitions to the number of possible repetitions (the total number of words recalled from the category minus one). The degree of clustering was not computed for neutral words because of the small number of words involved. The clustering scores for the pleasant words in the schizophrenic, nonschizophrenic, and normal groups were, respectively, .60 (SD = .14), .48 (579 = .13), and .S3 (SD = .17), and the group difference was not significant; the clustering scores for the unpleasant words were, respectively, .58 (SD - .24), .50 (SD = .18), and .50 (SD - .15), and the group difference was again not significant. Finally, the errors of intrusion and repetition in the free recall were counted. They were 1.3% in the schizophrenics, 3.9% in the nonschizophrenics, and 1.4% in the normals. Intentional Learning Multitrial jree recall. In the second session the subject was warned in advance that the multitrial free recall would follow the rating of the words. Figure 2 (left panel; top, right) summarizes the between-group comparison on all words recalled (regardless of pleasantness rating) as a function of the four trials. A 3

163

(group) X 4 (trial) analysis of variance (unequal means analysis), indicated no significant group effect but a significant trial effect, 77(3,147) = 114.84, p < .01. Figure 2 (left panel) also shows the between-group recall performance separately for the pleasant, unpleasant, and neutral words. The normals tended to recall pleasant words more than the other two groups, but neither the group difference nor the Group X Trial interaction was significant. The unpleasant-word recall also showed neither a significant group effect nor an interaction. The group effect for the neutral words was not significant, but the interaction was significant, 7?(6, 147) = 2.58, p < .05. Further analysis revealed that this interaction resulted from the faster learning rate for the schizophrenics than for the nonschizophrenics, 77 (3, 93) = 3.24, p < .02, but the recall difference between these two groups was not significant. The trial effect in all of these comparisons was significant: 77(3,147) = 54.94, p < .01, for the pleasant words; 77(3,147) = 65.21, p < .01, for the unpleasant words; 77(3, 147) = 44.90, p < .01, for the neutral words. Figure 2 (right panel, right) also shows the relative performance for the three types of words within each group as a function of trials. All three groups recalled the pleasant words more readily than the unpleasant words. This difference across the four trials was significant in the normals, £(18) = 4.79, p < .001, and in the schizophrenics, £(17) = 2.81, p < .02, but not in the nonschizophrenics. The normals and nonschizophrenics recalled the pleasant words better than the neutral words, but this difference was significant only in the normals, £(18) = 2.74, p < .02. On the other hand, the schizophrenics recalled the neutral words significantly better than the unpleasant words, £(17) =3.13,? < .01. Mnemonic organization. The output clustering on the basis of pleasantness features was first examined by means of the ratio of repetition. The mean ratios across the four trials for the pleasant words were .44 in the schizophrenics, .44 in the nonschizophrenics, and .53 in the normals; the ratios for the

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unpleasant words were, respectively, .49, .SO, and .54. The normal group's pleasant-word clustering was significantly higher than that of the schizophrenics, 2(35) = 3.27, p < .01, and the nonschizophrenics, 2(32) = 3.15, p < .01, but no group difference was found in the unpleasant-word clustering. Furthermore, although the normals' pleasant-word clustering was significantly higher than their unpleasantword clustering, 2(18) == 5.26, p < .001, the two types of clustering were approximately equal in the two patient groups. Another type of mnemonic organization that can be extracted from the multiple recall data is the subjective organization imposed by the subject himself independently of the experimenter's predetermined taxonomy. The extent to which the subject recalls a pair of words in contiguity on two successive trials (intertrial repetition) is taken as the measure of subjective organization. Handler and Dean's (1969) bidirectional measure of intertrial repetition was used. It is defined as the ratio of the observed intertrial repetitions to the maximum possible repetitions (the number of words common to both recall protocols minus one). The means of this measure over the three intertrials were .17 in all three groups. Finally, the mean errors of intrusion, repetition, and previous-list intrusion over trials were 3.1% in the schizophrenics, 4.7% in the nonschizophrenics, and 2.4% in the normals, and the group difference was not significant. DISCUSSION The major question addressed in the present study was whether the schizophrenic's deficit in the free recall task, which was repeatedly found in our previous works (Koh & Kay ton, 1974; Koh et al., 1973; Kayton & Koh, 1975; Koh et al., Note 1) would disappear if the subject were explicitly induced to attend to and encode the input words on the basis of the affective-semantic dimension. Using schizophrenic and normal subjects drawn from the same subject pool used in our previous works, the present study demonstrates that the storage and retrieval processes of schizophrenia become comparable to those of normals, when the materials have

been appropriately encoded, regardless of intention to learn. This finding is in agreement with the notions of the schizophrenic dysfunction in selective attention (e.g., McGhie, 1970) and in mnemonic strategy (e.g., Koh & Kayton, 1974). The results from the multitrial free recall task (second session) also indicate that the effect of the affectivesemantic encoding persists over the four trials, although there is a slight but noticeable decrease of the learning rate in the schizophrenics on the last two trials. In these comparisons the nonschizophrenic patients were largely indistinguishable from the schizophrenics. The differential recall of pleasant and unpleasant words is a topic of theoretical importance. Boucher and Osgood (1969), citing a considerable amount of cross-cultural and developmental evidence, concluded that "there is a universal human tendency to use evaluativety positive words more frequently, diversely, and facilely than evaluatively negative words" (p. 1). Rado's (1956) and MeehPs (1964) observations, however, lead us to believe that this universal tendency, which Boucher and Osgood call the Pollyanna tendency, may be defective in schizophrenia. Rado presumed the existence of a genetic deficit resulting in schizophrenic anhedonia. After treating many compensated schizophrenics, Meehl became convinced that these patients show a pronounced, pervasive, and relatively unmodified deficiency in the ability to experience pleasure. This clinical observation was tested by Kayton and Koh (1975), using the multitrial free-recall paradigm and subject groups comparable to the present study. They found that, while the normal young adults recalled pleasant words to a significantly greater degree than unpleasant words (the Pollyanna tendency), the young schizophrenic and nonschizophrenic patients who were at postpsychotic remission recalled both types of words equally poorly in the former group and equally well in the latter. The schizophrenics' recall deficit, furthermore, was found only for pleasant words. It was interpreted, therefore, that the absence of the Pollyanna tendency might be attributable to hypohedonia in the schizophrenics and to hyperscnsitivity to both

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pleasant and unpleasant affect in the non- precision and invoked on the strength of the schizophrenics, a group that consisted of pa- investigator's intuition" (p. 312), therefore, tients suffering from a variety of character is worth noting for future study. Second, the disorders. In the present study all three two organizational indices used in the present groups showed the Pollyanna tendency in study touch only a fraction of the strategies both sessions, recalling pleasant words more the subject might have adopted. Other stratoften than unpleasant words (Figure 2, right egies of organization, based on input order, panel). Apparently, the conscious attention opposite features (e.g., love-hate), thematic paid toward affective features and the en- content, and so on are also possible, and their coding operation performed on the basis of occurrence would reduce the magnitude of the those features served to "normalize" the clustering and subjective organization that we patient groups' Pollyanna tendency. measured. Moreover, the emphasis on affecThe organizational indices derived from the tive encoding in the present task might have recall data generally reinforce the above ob- suppressed the usually powerful semantic servations. The clusterings of both pleasant encoding, and this event, if in fact it ocand unpleasant words in the incidental learn- curred, would further reduce the size of the ing session were high and comparable among two measures. The principal finding of this study is that the three groups. In the intentional learning the three groups again showed marked clus- the recall performance of the schizophrenics, tering, although the normals' pleasant-word nonschizophrenics, and normals becomes comclustering was significantly greater than that parable once the subject has encoded the of the patient groups, and it was only in the materials according to their affective-semantic normals that the pleasant-word clustering- features. The schizophrenic deficit in rememwas significantly greater than the unpleasant- bering, therefore, would seem to be effectively word clustering. The subjective organization, remediable by means of the encoding treaton the other hand, was small but equal among ment, Koh, Kay ton, and Schwarz (1974) the three groups. Both indices of mnemonic reported that the subjective lexicon or the organization failed to differentiate between semantic memory network of the schizothe schizophrenics and the nonschizophrenics. phrenic is probably intact. Apparently, schizoBecause the to-be-remembered words were phrenics are less able than normals to utilize clearly encoded in terms of their affective this storage structure in deriving their mnefeatures at the time of storage, we expected monic strategies. The experimentally maniputhat the pleasantness categories would serve lated encoding and unitization in the present as effective retrieval cues, as suggested by the experiment induced them to interact actively principle of encoding specificity (Tulving & with this structural asset which is adequate Thomson, 1973), but such categories were and, in consequence, served to remedy their found to be ineffective as retrieval cues. It recall deficit. This induced interaction cermay be fruitful to speculate about the reasons tainly corresponds to what Craik and Lockhart for these unexpected results. First, perhaps it (1972) call the depth of elaboration or the is misleading to equate affective encoding higher level of information processing, which with semantic encoding (e.g., Jenkins, 1974). is essential for efficient recall. The pleasantness categories we used, for exREFERENCE NOTE ample, differ from semantic or conceptual 1. Koh, S. D., Kaylon, I/., & Schwarz, C. Rememcategories in the sense that the former constibering of connected discourse by young nonpsytute a more or less personal, idiosyncratic, chotic schizophrenics. Paper presented at the 20th and ordered continuum, which implies loose International Congress of Psychology, Tokyo, August 1972. and flexible categorical boundaries, whereas the latter consists of relatively fixed and disREFERENCES crete concepts based primarily on social conBauman, E. Schizophrenic short-term memory: A sensus. Postman's (1975) observation that deficit in subjective organization. Canadian Joursemantic processing "is a concept lacking in nal oj Behavioral Science, 197t, 3, 5S-6S.

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