Behat?. Res. Ther. Vol. 21, No. 3, pp. 233-239, 1983 Printed in Great Britain. All rights reserved

OOOS-7967/83/030233-07$03,00/O Copyright % 1983 Pergamon Press Ltd

MOOD AND THE SELF-REFERENCE BIAS IN RECALL

ANDREW MATFEWS* and BRENDAN BRADLEY?

St George’s Hospital Medical School, Cranmer Terrace, Tooting, London SW17 ORE, England

Summary-Hypotheses linking a negative recall bias (or negative self-schema) with vulnerability to depression were tested using an experimental mood-induction task. Extent of bias in student subjects was found to be unstable over a 4-month period, but different measures of memory bias within one session were highly correlated. Marginally significant correlations in the expected direction were found between estimates of recall bias and mood state, whether measured at the same or at different times. Change in mood following induction did not relate to change in bias. suggesting that the observed differences in recall are not a simple function of transient mood state alone. Equally, the initial recall bias did not predici the extent of mood shift following induction. as would be expected if a negative self-schema deternlined ease of mood shift in a negative direction. However, significant correlations were found between negative recall bias and self-reported frequency and severity of depression, lending equivocal support to the negative self-schema model.

INTROIJUCTION

In an earlier paper, we reported previous findings of an advantage in recall for material that had been encoded with reference to oneself (Bradley and Mathews, 1983). Normal subjects recalled more adjectives after having rated whether they were self-descriptive, than after having rated whether they were descriptive of others. Such results have often been interpreted as evidence for a self-schema; that is, a well-elaborated knowledge structure in memory concerning the self (see Markus, 1980; Kuiper and Derry, 1981). Depressed patients do not show such a general recall advantage following a self-referent encoding task, except in the case of negative words (that is, those relevant to depressive ideation or mood). This difference may indicate that individuals vulnerable to depression are characterized by having a permanent “negative self-schema”, or it could indicate that depressed mood has the temporary effect of rendering positive material less accessible from memory.

The first possibility is consistent with the views of Beck (1976), to the effect that learning experiences can establish various cognitive schemata conducive to depressive thinking, although the schemata may remain latent until subsequently primed by events. The problem here is that if the hypothesized schemata are not observed (e.g. Lewinsohn, Steinmetz, Larson and Franklin, 1981) their absence can always be attributed to their latent status, making the model difficult to falsify. Initially therefore, we chose to examine the more testable hypothesis that observable evidence of a negative self-schema would be associated with vulnerability to depression.

An alternative hypothesis mentioned earlier, is that negative bias in recall is entirely attributable to temporary mood state. If this is the case, then the induction of a negative mood would always produce the same recall bias, irrespective of idiosyncratic cognitive structures. Mood induction has indeed been shown to result in a recall bias with normal subjects (Teasdale and Fogarty, 1979; Teasdale and Russell, 1983). When made to feel temporarily despondent using the Velten mood-induction task (Velten, 1968) subjects recalled fewer happy memories or positive adjectives, and more unhappy memories or negative adjectives, than did the same subjects made to feel elated. Although it remains di~cult to rule out semantic priming as an explanation of the V&en task effect. these results suggest that the negative self-schema observed in depressives may be attributed to their mood state rather than to a stable cognitive characteristic.

At first sight, results from the two experimental paradigms used seem quite different. For exampie, in the paradigm used by Bradley and Mathews, depressives did not show a genera1

*To whom all reprint requests should be addressed. TPresent address: Department of Psychology. Institute of Psychiatry, De Crespigny Park. London SE5 8AF, England.

234 ANDREW MATHEWS and BRENDAN BRADLEY

negative bias but only when asked to judge words in relation to themselves. In relation to others, depressives showed a tendency to recall more positive words. However, in the paradigm used by Teasdale the instructions given would probably encourage self-reference, and thus be equivalent to the condition in which we asked depressives to judge whether words were self-descriptive. Thus it may be the case that any individual made to feel depressed will show an equivalent negative bias in both paradigms, but one which is specific to self-referent material. Both results could be explained using the network model of mood and memory suggested by Bower (198 1) which predicts such mood-dependent effects on recall. Since individuals will have had selective exposure to both unpleasant words and events while experiencing negative mood, the re-arousal of the same mood will facilitate access to related words and memories within the self-schema. As a result, negative recall bias may be seen as a joint function of both mood and idiosyncratic cognitive structure.

The present study examined a number of predictions relevant to these possibilities; namely, that the presence of a negative cognitive bias will predict vulnerability to depressive experiences, or that the negative cognitive bias depends on current mood state. Although these hypotheses can be stated in mutually exclusive form for the purposes of testing, as indicated above it would also be possible to suggest a mutual interaction between mood and negative bias.

Using a selective sample of normal subjects, we set out to test the following questions:

1. Is the extent of bias in memory a stable individual characteristic? 2. Is bias determined by current mood state? 3. Does bias predict the reaction to the mood-induction task? 4. Does bias predict self-reported vulnerability to depression?

METHODS

Subjects were selected from a larger group who were tested using a brief version of the Self-Referent Adjective Recall Task. A subsample chosen to represent those scoring at the extreme ends of the distribution in bias, were asked to re-attend 4 months later for retest. Subsequently, they were given a brief version of the memory task used by Teasdale et al.; negative mood was induced using a combination of Velten phrases and appropriate music, and they were then retested on the same memory task. Ss then completed a questionnaire asking about the frequency, intensity and duration of depression in their experience.

Seventy-three first-year medical students volunteered to take part after the nature of the experiment had been described in general terms, as part of an introductory lecture on psychology. On the basis of the results from this first test, a selective subset of students were asked to return some time later for retesting. Twenty-one Ss returned, 12 men and 9 women, and these were paid for their participation.

Measures

(a) Mood ratings. In Session 1, Ss completed the depression items from the Multiple Affect Adjective Checklist (DACL, Zuckerman and Lubin, 1965) for how they were feeling at that time. In Session 2, they rated the degree to which they were currently feeling “miserable or sad”, “happy” and “worried” using lo-cm visual analogue scales. The score for each scale was the distance between the mark made by the S on each line and the appropriate end point (labelled “not at all” and “extremely”).

(b) Personal Adjectke Recall Bias (PAB). Twenty-nine adjectives were presented using a carousel projector which automatically displayed each word for 6 set, followed by a delay of 2 set before the next was presented. The first 3 adjectives presented were examples, and of the remaining 26, 13 were positive and 13 negative in affective tone. For example, positive adjectives used included “jolly”, “good” and “capable”, while negative ones included “unfortunate”, “dull” and “sad”. Instructions given to each S were

“I would like you to judge whether each word describes you or not and to circle the

appropriate letter (Y for yes, N for no or I for irrelevant) against the number that

Mood and bias in recall 235

corresponds to the number on the slide. You have 6 set to make your decision for each word. Please do not make any special attempt to remember the words and do not think back to earlier words.”

After presentation of the words, Ss were asked to count backwards from 100 in threes for 20 set, writing their answers down. They were then asked to recall as many words as they could within a period of 2 min.

(c) Personal Memory Recall Bias (PMB). Four lists of 20 neutral nouns were used. Two noun lists were presented before the depression-induction task, and two afterwards. For the first list given on the first occasion, Ss were asked to look at each word and to think of a happy memory which was in some way connected with that word. Two minutes were allowed for each list and Ss were asked to tick each word as soon as a suitable memory was recalled and then go on to the next word. For the second list on the first occasion, Ss were asked to think of unhappy memories in a similar way. For the second pair of lists the order was reversed, that is unhappy memories were recalled first followed by happy memories. The instructions given emphasized the need to complete as many items as possible, leaving words that did not quickly elicit a relevant memory.

(d) Ratings of vulnerability to depression. Three ratings were made by each S of frequency, severity and duration of past depressive mood. In each case Ss rated their answers on lo-cm lines divided into five equal intervals. Appropriate descriptors were placed at the anchor points on each line, although Ss were invited to mark the line at any appropriate point. The precise questions asked were

(1) “How often do you feel miserable or sad?” (2) “If or when you get miserable or sad, how bad is it on average?” (3) “How long does each period of feeling miserable or sad last on average?’

Finally Ss were asked to indicate how long ago was the last time (if ever) that they felt continuously miserable or sad for a few days or more.

PROCEDURE

Session 1

This session was conducted in a class of 73 pre-clinical medical students, and lasted 20min. Orienting instructions were given to the effect that we were interested in personal judgements, mood and memory, and that further details would be available for those interested. The Personal Adjective Recall Task was then presented as described earlier, and Ss were required to record their responses in a booklet. They were then asked to complete the mood scale (DACL), before handing in the booklet.

Session 2

Subjects showing a wide scatter of scores on the initial test (PABl) were invited to attend for retest about 4 months later. Students were selected in order to ensure that there would be an adequate representation of those showing better recall for either positive or negative adjectives, and of those selected about two-thirds were eventually seen (n = 21). The rationale given to this subgroup of students was that their initial result proved to be of interest, and that we wished to repeat the test to confirm them. Session 2 began with the mood ratings, followed immediately by re-presentation of the Personal Adjective Recall Test (PAB2) using a different but matched set of adjectives. After the recall phase, and a repeat of the mood rating, Ss were asked to complete the Personal Memory Recall Task (PMBl), with happy memories being recalled before unhappy memories. Mood was then rated once more, prior to performing the depression-induction task.

The depression-induction task was introduced with instructions as follows:

“I would like you to try and put yourself in a miserable or sad mood, and I shall play some music and give you some statements to read in order to help you feel miserable or sad. Try to get yourself into the mood suggested by the statements on the card in front of you, and spend about 15 set reading each statement, going back to earlier statements if time permits. Think of ways in which the statements could apply to you,

236 ANDREW MATHEWS and BRENDAN BRADLEY

or times when you have felt that way. This is the most important part of the experiment and so I would ask you to try as hard as possible to produce a low mood using both music and the statements in order to help you do this.”

Twelve statements were used, such as “I feel heavy and sluggish”, “things seem futile, pointless” (Teasdale and Taylor, 1981). The music played at the same time (Russia under the Mongolian Yoke, by Prokofiev, played at half speed), like the statements described above, has been reported by other workers to have a depressing effect.

Immediately after completion of the depression-induction task, Ss re-rated their mood, and continued directly to the second version of the Personal Memory Recall Task (PMB2), before once again re-rating their mood. The questionnaire concerned with previous experiences of depression was then administered. The procedural sequence is illustrated in Fig. 1.

(a) Mood rating (I) (b) Presentation of self-reference adjectives interference task followed by recall (PABZ)

(c) Mood rating (2) (d) Recall of happy and unhappy personal memories (PMBl)

(e) Mood rating (3) (f) Depression-induction task

(g) Mood rating (4) (h) Recall of unhappy and happy personal memories (PMB2)

(i) Mood rating (5) (j) Questionnaire on proneness to depression

(k) Mood rating (6)

Fig. I. Procedural sequence in Session 2.

RESULTS

Two different measures of memory bias were first computed: one derived from the PAB test and a second from the PMB test. In both cases, a ratio was calculated based on the difference between the number of pleasant and unpleasant adjectives or memories recalled, divided by the total number of recalled items. Thus, where P is the number of pleasant items and U the number of unpleasant items, the measure of bias used corresponds to (P - U)/(P + U). This ratio measure was considered to be the best way of adjusting for differences in overall recall scores. Positive scores on the measure reflect a recall bias for positive or happy items.

Although the original intention had been to contrast Ss scoring either high or low on both PABl and PAB2, as will be seen shortly, a simple division of Ss into two groups was complicated by the unreliability of this measure, and the data were analysed for the most part using product-moment correlations.

The stability of the Self-Referent Adjective Memory Bias (PABI and PAB2) was assessed by correlating the scores obtained 4 months apart. The obtained correlation was non-significant (r = 0.27) suggesting that in this non-depressed sample there is little stability over 4 months. On the other hand, significant relationships were found among measures of bias obtained during Session 2 (PAB2, PMBl and PMB2). As can be seen from Table 1, all measures obtained on the same occasion intercorrelate highly, showing high immediate test-retest reliability (PMBl x PMB2, Y = 0.86) and a significant relationship between the two different measures of bias used (PAB2 x PMBl, r = 0.54; PAB2 x PMB2, r = 0.60). All measures of memory bias except PMB2 correlated significantly with the DACL mood rating made in Session I (see Table 1).

Effectiveness of the mood-induction procedure in Session 2 was tested by carrying out dependent t-tests on mood ratings immediately before and after induction. All three scales showed significant

Table 1. Correlations among measures of memory bias and DACL

PABl PAB2 PMBI PMB2

PAB?

0.27

PMBI

0.28 0.54**

PMB2

0.19 0.60** 0.86***

DACL

-0.41*** -0.59** -0.52** -0.39

**P < 0.01: ***p < 0.001

Mood and bias in recall 231

Table 2. Correlations between measures of memory bias and initial mood ratings, and those after the induction task, for Session 2

Initial mood ratings Post-induction mood

Sad Happy Worried x Sad Havvv Worried x

PAB2 -0.06 0.35 -0.27 0.32 -0.13 0.29 -0.41 -0.37

PMBI 0.24 0.14 0.29 0.16 -0.30 0.45* -0.07 -0.39

PMB2 0.30 0.03 0.13 -0.13 -0.37 0.53** - 0.20 -0.51**

*P < 0.05: **p < 0.01.

changes, with Ss rating themselves as more sad (P < O.OOl), less happy (P < 0.001) and more worried (P < 0.05). However, there was a trend for mood to become more negative as the experiment progressed, (e.g. after PMBl). For this reason pre-induction mood refers only to the initial level, rated at the beginning of the experiment. Measures of mood both before and after induction were correlated with measures of memory bias. At the beginning of the session, none of these correlations were significant, suggesting that the bias measures were not simple functions of rated mood state. However, some correlations between bias measures and mood state obtained later were significant, as can be seen in Table 2. To simplify the mood data, a composite score was calculated (sad + worried - happy). Although the highest correlation was obtained between the measure of memory bias obtained after induction (PMB2) and mood at the same time, correlations between mood and measures of bias obtained earlier also approached significance. These correlations indicate that there is a tendency for Ss with high positive memory bias to report feeling more happy (and less worried) after, but not before mood induction in Session 2.

Mood changes following the induction task were then calculated by subtracting the rating obtained after induction from that obtained beforehand. As before, correlations were calculated between these ratings of mood change and the various measures of memory bias (see Table 3). Contrary to prediction, there were no significant relationships between mood change and measures of bias obtained before induction, but only with that obtained afterwards (PMB2). Similarly, there were no significant correlations found between mood change and the change in bias (PMBl - PMB2). In further analyses, 5’s were divided into groups scoring relatively high and low on each memory bias measure, and an independent “t”-test calculated for mood-change scores. Once again, there was no significant effect on mood-change scores associated with measures of memory bias obtained prior to induction.

Finally, memory bias measures were correlated with reports of proneness to depression. All measures of memory bias in Session 2, whether obtained before or after mood induction, correlate significantly with self-report of frequency of depression, while PABl and PMBl correlate with severity. The highest correlation, both for frequency and severity, was obtained with PMBl (see Table 4). Perhaps surprisingly, these ratings of depression proneness did not correlate with the extent of mood shift following the mood-induction task, although they did with the final composite mood rating (See Table 4).

DISCUSSION

Concerning the first hypothesis tested in this study, it would appear that the extent of negative bias in the recall of self-referent adjectives is not a stable characteristic, at least in the present group of subjects. It may be of course, that in older subjects, or more extreme groups (such as clinical populations) differences across subjects would be stable for longer periods. On the other hand, there

Table 3. Correlations between memory bias measures and mood changes from immediately before to immediately after induction

Changes in mood

PAB2 PMBI PMB2

Sad HIPPY

-0.12 -0.07 -0.33 0.28 -0.42 0.41

Worried

-0.05 - 0.04 -0.23

x

-0.06 -0.30 - 0.47*

*P < 0.05

238 ANIXCEW MATHEWS and BREN~AN BRADLEY

Table 4. Correlation between memory bias measures, final mood score, and self-rated proness to depression

Depression-Proneness Questionnaire

Frequency Severity Duration x

PABl -0.38 -0.46* -0.05 -0.35 PAB2 -0.52* -0.33 -0.08 -0.39 PMBI -0.70*** - 0.49* -0.16 -0.56** PMB2 -0.58** -0.35 -0.02 -0.38 Mood 0.43 0.43* 0.48* 0.55**

*P < 0.05; **p < 0.01; ***p < 0.001.

is a degree of stability in the measures of bias since within the one session the ratio of happy to unhappy memories was fairly reliable, and the different measures of bias (PAB and PMB) also overlapped considerably. The longer-term instability of the adjective recall measure might suggest that negative bias is a function of a fluctuating characteristic, such as mood state, but here the evidence is mixed.

Significant correlations were found between recall bias and the DACL in Session 1. Neither of the two memory measures employed showed significant correlations with self-rated mood at the beginning of Session 2, although occasional significant correlations were found between extent of bias and later mood state after mood induction. This difference may be a function of different mood measures, but since the DACL was done at the end of Session 1 it may also have been influenced by the earlier recall task (PABl). When mood was manipulated, relatively more negative memories were recalled, as expected from earlier studies. However, the extent of change in negative mood did not predict the extent of change in memory bias. Thus, despite some positive evidence (see also Teasdale and Taylor, 198 l), it seems unlikely that current mood is the sole determinant of negative bias, although it does appear to be a contributing factor. Hypothesis two is thus only partially supported.

Hypothesis three concerned the role of negative bias in predicting response to the mood- induction task. Correlations between initial measures of recall bias and subsequent change in mood were generally not significant. Instead only the measure of bias after induction related to mood change, so that hypothesis three was not supported.

Somewhat more convincing support emerged for the last hypothesis, that individuals with a high negative bias would be more likely to report frequent periods of depression. Both measures of memory bias were related to reported frequency and severity of depression. Obviously there is some doubt about the validity of such a simple self-report measure, which might itself be influenced by mood state at the time. However, despite significant correlations between mood and reports of depression, it seems unlikely that this is the explanation. Rated severity of depression also correlated with PABl, done 4 months earlier, and thus can hardly be attributed to mood state in Session 2. Alternatively, the relationship between self-reported depression and negative bias in memory may be attributable to selective recall. Individuals who can easily access examples of earlier depressed periods due to such bias, may then overestimate their frequency or severity due to use of the availability heuristic (Tversky and Kahneman, 1974). Finally, subjects’ report of depressive episodes might be valid, but the present negative bias could be the result, rather than the cause of previous depression. Such alternative explanations are not inconsistent with the hypothesis as stated, but do raise questions about the explanatory power of the observed relationship.

The associations discussed above are summarized in Fig. 2, in which arrows indicate possible directions of influence. As can be seen from the figure, modest relationships were found between estimates of mood and memory bias, without clearly favouring either direction of causality. Since memory bias relates to mood, and vice versa, the results may appear consistent with a circular model of depression (Teasdale and Russell, 1983).

Failure to find a clearer relationship between experimentally-induced changes in mood and changes in accessibility bias was unexpected however, and raises questions about a directly causal relationship between them. Also the closer relationship of mood shift with personal memories than with the Adjective Recall Task suggests the possibility that the recall of unhappy personal memories is involved in the mood-induction task, contrary to the suggestion of Teasdale and Taylor (1981).

239 Mood and bias in recall

o’:.~??_o~~, \;;~

Reports of 26~~

r?-

0.9

previous

depression qE&y

- 0.4

Fig. 2. Summary of correlations found among variables.

Furthermore, since we found no relationship between the experimentally-induced mood change, and reports of naturally-occurring depression, we remain sceptical of the relevance of the induction task. Possibly the extent of mood change in the laboratory is too confounded with individual differences in compliance, effort or suggestibility. The validity of induction tasks could usefully be examined further before a relationship with naturally-occurring depressive episodes can be assumed. Needless to say, an equal caveat should be applied to self-rated vulnerability to depression.

Despite this, the relationship between self-rated frequency and severity of depression and a negative memory bias is the most promising result of this study. If valid, it would imply support for the first possibility discussed in the Introduction, that cognitive schemata conducive to negative thinking render people prone to depression. Such a conclusion would seem to run counter to the findings of an important study by Lewinsohn et al. (1981) who found no evidence of cognitive

distortions in questionnaires completed by individuals who later became clinically depressed, or who had already recovered from depression. These authors concluded that cognitive distortions were the consequence, rather than the cause of depression. In the present study, our measure of the self-schema proved unstable over time, and did not predict experimental mood change, both of which seem to point in the same direction. On the other hand, there is no reason to expect the self-schema to be completely stable, especially in young people, and we have earlier cast doubt on the validity of experimental mood change. Measures of memory bias might be less transparent than cognitive distortion questionnaires, so that one obvious need is to examine memory bias in people who have been, or will later become clinically depressed.

A final possibility that remains to be investigated was indicated earlier in the Introduction to the present study. Despite the difficulty of verification, it remains quite possible that organizing schemata relevant to depression are not readily accessible to consciousness. This possibility could be investigated by studying cognitive reactions to depressing events, or by developing other experimental paradigms that prime the hypothesized schemata, and thus make their products observable.

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