Explicit Memory Bias Research Articles

Perceptual and memory biases for health-related information in hypochondriacal individuals

Problematic health concerns characteristic of hypochondriasis may be better understood with the aid of cognitive, information processing theories. We investigated whether hypochondriacal individuals show perceptual and explicit memory biases favoring health-related information. A clinical sample of hypochondriacs (n=18) and healthy controls (n=22), and a sample of hypochondriacal (n=22) and nonhypochondriacal (n=67) patients referred for Holter monitoring, completed a computerized test of perceiving difficult-to-read words and then an encoding task followed by recall of those words. Contrary to our prediction, hypochondriacal individuals in the clinical sample did not perceive more health- related words than words not related to health. Hypochondriacal individuals in the Holter-monitoring sample showed an unexpected bias against reporting health-related words. Social class may account for some of the group differences in this sample. Hypochondriacal individuals in both samples showed better memory for health-related than nonhealth words.

Implicit and explicit memory for threat words in high- and low-anxiety-sensitive participants

This study examined memory for anxiety andthreat words in high-anxiety-sensitive (HAS; n = 38) andlow-anxiety-sensitive (LAS; n = 36) participants. Basedon Foa and Kozak's (1986) information processing theory of fear, it was hypothesized that HASparticipants would remember anxiety and threat-relatedinformation better than LAS participants and thatphysiological arousal would enhance this difference. Support for the first hypothesis was limited.Anxiety sensitivity did affect explicit memory but onlyfor general threat words, not for anxiety words. HASparticipants recalled significantly more threat words than neutral, positive, or anxiety wordswhereas LAS participants recalled significantly morepositive words than neutral or anxiety words. HASparticipants also recalled significantly more threat words than LAS participants. Thus, HASparticipants exhibited an explicit memory bias forthreat words, but, unexpectedly, not for anxiety words.No implicit memory differences were found. Inconsistent with the second hypothesis, the arousalmanipulation (i.e., hyperventilation) had no effect.Because anxiety sensitivity is a cognitive risk factorfor panic disorder, these results suggest that memory biases for threat may exist in patients priorto the onset of the disorder, perhaps even before thefirst unexpected panic attack.

Implicit and explicit memory for shape, body weight, and food-related words in patients with anorexia nervosa and nondieting controls.

Twelve patients with anorexia nervosa and 12 control participants watched a series of 64 words. There were 4 word types: anorexia related, positive, negative, and neutral. The last 3 types were anorexia unrelated. Anorexia-related words had the same affective valence as the neutral control words. Next, the participants completed an explicit memory test (cued recall) and an implicit memory test (word stem completion). Results showed a strong explicit memory bias for anorexia-related words for patients with anorexia nervosa but not for nondieting controls. There was no evidence for a similar bias in implicit memory. Results are discussed in the context of cognitive biases in psychopathology.

Explicit and implicit memory bias in panic disorder with agoraphobia

Thirty patients with a diagnosis of panic disorder with agoraphobia and 30 normal controls were compared on explicit memory (cued recall) and implicit memory (word stem completion) for positive, neutral, social threat, and physical threat words. The panic patients showed an explicit memory bias, but no implicit memory bias, for physical threat words. The index of explicit memory bias for physical threat words was found to correlate with anxiety sensitivity and degree of agoraphobic fear and avoidance. The index of baseline bias for threat words on the word completion task, on the other hand, correlated with trait anxiety. Although there were no correlations between explicit and implicit memory bias for physical threat words, explicit memory bias for physical threat words correlated with explicit memory bias indexes for positive words and social threat words. The results are discussed in terms of the functional role of an explicit memory bias for physically threatening events in panic disorder. The negative results on implicit memory bias are discussed in relation to earlier studies, the use of different implicit memory tasks, and the role of baseline bias on implicit memory tasks. Finally, the hypothesis is suggested that explicit and implicit memory bias for emotional information may represent two different styles of information processing, which serve as vulnerability factors for different emotional disorders.

Explicit and implicit memory bias in social phobia. The role of subdiagnostic type

Fourty-five patients with social phobia and 45 normal controls were compared on explicit memory (cued recall) and implicit memory (word stem completion) for positive, neutral, social threat, and physical threat words. Although there were no significant differences between the social phobics and the normal controls, the subgroup of patients with non-generalized social phobia showed an implicit memory bias for social threat words. The results are discussed in terms of a critical analysis of the concept of implicit memory bias, which is operationalized as the difference between a bias on primed and unprimed words, and where the latter represents a “baseline bias”. In the present study, this baseline word completion bias for social threat words showed a strong negative correlation ( r = − 0.72) with the implicit memory bias for social threat words, and showed positive correlations with several psychopathology-related measures among the social phobics. It is suggested that future research should consider results on both implicit memory bias and its corresponding baseline bias. The possibility is discussed that implicit memory bias and baseline bias may serve as indexes of externally and internally generated priming effects, and that the relative contributions of external and internal priming may differ in different subtypes of social phobia.

Cognitive bias and memory performance in patients with persistent insomnia

Twenty patients with primary insomnia were compared with 20 normal controls, matched for age, sex, and educational level, on a modified version of the emotional Stroop test, and tests of explicit and implicit memory for threat words and non-threat words. The results showed that the insomniacs had a prolonged Stroop latency for sleep words, but so did the controls, and there was no group difference on Stroop interference of sleep words. The insomniacs showed no explicit or implicit memory bias for threat words, and they did not differ from the controls on explicit or implicit memory performance. They did differ from the controls, however, by scoring lower on the WAIS-R vocabulary test, and by having lower expectations of their explicit memory performance before testing, although they did not differ from the controls on how they evaluated their memory performance after testing. The results are discussed in terms of a possible deficit in semantic memory in insomniacs.

Effects of Level of Processing on Implicit and Explicit Memory in Depressed Mood

Recently, several studies have addressed the question of whether depression affects priming in implicit memory tasks. The main aim of this experiment was to assess the presence of a bias for negative information in explicit memory (free recall) and implicit memory (word-stem completion) tasks among subclinically depressed subjects compared to nondepressed subjects, using the typical levels of processing manipulation. The results of this study show the existence of a mood-congruent memory bias for both implicit and explicit memory in depressed subjects. The theoretical implications of these findings for implicit and explicit memory biases associated with depressed mood are discussed.

Unconscious mood-congruent memory bias in depression.

The purpose of this study was to investigate an unconscious or implicit mood-congruent memory (MCM) bias in clinical depression. Many studies have shown an explicit memory bias, but no study has yet found an implicit MCM bias in clinical depression. The authors compared depressed and control group participants on a conceptually driven implicit memory test. After studying words of positive, neutral, and negative affective valences, participants produced free associations to various cues. Implicit memory or priming was demonstrated by the production of more studied than unstudied words to the association cues. Depressed participants showed more priming of negative words, whereas controls showed more priming of positive words, thus supporting the MCM pattern. Also, no implicit memory deficit was found in depressed participants. These findings are discussed in the context of several prominent theories of cognition and depression.

Implicit and explicit memory for emotion-congruent information in clinical depression and anxiety

Implicit and explicit memory biases were assessed in clinically depressed ( n = 19), clinically anxious ( n = 17), and normal control ( n = 18) Ss. The implicit memory test was a primed lexical decision task, with anxiety- and depression-relevant words, and suprathreshold and subthreshold primes. The explicit memory test was incidental free recall of self-referenced words. The depressed group showed greater suprathreshold and subthreshold priming effects for depression words, and recalled more depression words, than the other two groups. These results suggest that clinical depression, but not clinical anxiety, is associated with mood-congruent biases in both automatic and strategic memory processes.

Implicit and explicit memory bias in anxiety: A conceptual replication

Williams, Watts, MacLeod and Mathews' (1988) [ Cognitive psychology and the emotional disorders. Chichester, Wiley] model of anxiety and cognition leads to the prediction that anxious subjects will show an implicit, but not an explicit, memory advantage for threat-related information. Mathews, Mogg, May and Eysenck (1989) [ Journal of Abnormal Psychology, 98, 401–407] obtained marginally significant support for this prediction in an experiment that tested memory using word stem completion tasks following a self-referent encoding procedure. However, neither the reliability nor generality of these findings have been established. The current experiment was designed to provide a conceptual replication of Mathews et al.'s study, using different tests of implicit memory (i.e. tachistoscopic identification) and explicit memory (i.e. recognition) and an alternative type of encoding task (i.e. colour naming stimulus words). 16 generalised anxiety disorder patients, and 16 non-anxious control subjects were tested. As predicted, the anxiety patients showed a relative implicit memory advantage for threat-related stimulus words, while the two subject groups did not differ in their pattern of explicit memory performance. These results support the predictions generated by Williams et al.'s model of anxiety and cognition.

Implicit and explicit memory bias in depressed and non depressed subjects

Abstract Two experiments were carried out to investigate a possible mood-congruent memory bias in explicit memory (free-recall test) and implicit memory (word-stem completion task) for positive and negative words in depressed and non depressed college students. A comparison of implicit and explicit mood-congruent memory bias should help to reveal cognitive processes involved in this effect. The results of both studies indicated that depressed subjects showed a memory bias not only on the traditional explicit memory task, but on the implicit memory task as well. The theoretical implications of these results are discussed.

Implicit memory bias, explicit memory bias, and anxiety

Abstract Normals high, medium, and low in trait anxiety performed two encoding tasks (one predominantly data-driven and the other conceptually driven) on threat-related and neutral words, followed by tests of word completion, cued recall, and free recall. Memory performance indicated the existence of negative memory biases in the high trait-anxious group, but it was generally not possible to decide whether the biases were associated with trait anxiety rather than with depression. The biases were obtained mainly when there was a match between the processes at encoding and those at the time of test, whether the matching processes were predominantly data-driven or conceptually driven. Implications of these findings for implicit and explicit memory biases associated with high trait anxiety are discussed.

Implicit and explicit memory for catastrophic associations to bodily sensation words in panic disorder

This study investigated explicit (cued recall) and implicit memory (word completion) memory bias for catastrophic associations among individuals with panic disorder (n=24), clinician controls (n=24), and normal controls (n=24). Compared to both control groups, the panic disorder group showed biased explicit and implicit memory for catastrophic associations to bodily sensation words (e.g., palpitation-coronary) compared to positive (e.g., smiles-elation) and neutral (e.g., groceries-coupons) word pairs of equal relatedness. These results support cognitive formulations of panic disorder which suggest that individuals with panic disorder have biased memory for

The effect of high and low trait anxiety on implicit and explicit memory tasks

Abstract Two experiments were conducted assessing the presence of explicit and implicit memory biases for threatening material in high and low trait anxious college students. No implicit memory bias for threat words was found in either experiment. Futher, an explicit free recall bias for threat words in anxious subjects was found in Experiment 1, but was not replicated in Experiment 2. The inconsistent research literature on memory biases in anxious individuals is discussed and directions for future research are highlighted.

Implicit and explicit memory and response bias

The influence of response bias on tests of implicit and explicit memory was assessed by using word-stem completion and recognition. During acquisition, subjects were presented either with a list of words unrelated to the task in the retrieval phase or with a list of words whose stems could be completed in only two ways (e.g. “appeal,” “appear”). In the word-stem-completion retrieval phase, the subjects, who were given either explicit or implicit memory instructions, were asked to complete these stems. Retrieval of items in implicit and explicit memory tasks was highly correlated (r =.593 and.625, respectively) when the acquisition list had contained the words completing the stems and similarly correlated (r =.667) when the acquisition list had contained no words completing the stems. There was no correlation between recognition and explicit stem completion. In contrast to stem completion, there was no overall correlation between “recognition” in the condition in which the acquisition list contained words to be recognized later and the guessing condition, in which the acquisition list had contained no words presented during the retrieval phase. However, when the items were divided into two groups differing in memorability, a negative correlation appeared between recognition and guessing probability with the more memorable items, and a positive correlation appeared with the less memorable items. This suggests that response bias, rather than the memory the tasks are designed to test, is responsible for the normally reported lack of correlation between recognition and word completion.

Recollective experience and recognition memory for threat in clinical anxiety states

Recognition memory for threat and nonthreat words was examined in generally anxious patients in relation to normal control subjects. Two types of response in recognition memory (“know” and “remember”) were used to test predictions from Williams, Watts, MacLeod, and Mathews’s (1988) cognitive model of anxiety. The results failed to support the hypothesis that anxiety is associated with an implicit memory bias favoring threat (as measured by “know” responses) and an explicit memory bias against threat (as measured by “remember” responses). The findings are discussed in relation to recent research which suggests that there are two functionally independent systems within implicit memory.

Implicit and explicit memory bias for threat in post-traumatic stress disorder

We investigated explicit (cued recall) and implicit (word completion) memory in Vietnam combat veterans with ( n = 24) and without ( n = 24) post-traumatic stress disorder (PTSD). Half of the subjects in each group encoded combat, social threat, positive, and neutral words elaboratively, whereas the others encoded these words nonelaboratively. On the cued recall test, under both encoding conditions, both groups recalled more combat words than other words. However, difference scores obtained by subtracting the mean recall for neutral words from the mean recall scores for the other words revealed that PTSD patients exhibited a relative explicit memory bias for combat words. That is, PTSD patients tended to exhibit poor memory for everything but combat words. On the word completion test, only PTSD subjects exhibited an implicit memory bias for combat words. This bias was greater for primed than for unprimed words, thereby ruling out a response bias. Such memory bias may underlie the ‘reexperiencing’ symptoms characteristic of PTSD (e.g. intrusive thoughts, nightmares).

Implicit and explicit memory bias in anxiety.

Implicit and explicit memory bias in anxiety.

Implicit and explicit memory bias in anxiety.

Previous investigations of recall and recognition for threatening information in clinically anxious subjects have yielded equivocal results. The present study contrasts implicit (word completion) with explicit (cued recall) memory and shows that indices of bias for emotional material derived from the two types of memory are independent of one another. The explicit measure was correlated with trait anxiety scores, but did not clearly distinguish between subjects with clinical anxiety states and normal control subjects. On the implicit memory measure, clinically anxious subjects produced more threat word completions, but only from a set to which they had recently been exposed. These results are taken as evidence that internal representations of threat words are more readily or more persistently activated in anxiety states, although they are not necessarily better elaborated.