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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Updating the contents of working memory in depression: Interference from irrelevant negative material.

This study was designed to assess the effects of irrelevant emotional material on the ability to update the contents of working memory in depression. For each trial, participants were required to memorize 2 lists of emotional words and subsequently to ignore 1 of the lists. The impact of irrelevant emotional material on the ability to update the contents of working memory was indexed by response latencies on a recognition task in which the participants decided whether or not a probe was a member of the relevant list. The authors compared response latencies to probes from the irrelevant list to response latencies to novel probes of the same valence (intrusion effect). The results indicate that, compared to control participants in both neutral and sad mood states, depressed participants showed greater intrusion effects when presented with negative words. In an important finding, intrusion effects for negative words were correlated with self-reported rumination. These findings indicate that depression is associated with difficulties removing irrelevant negative material from working memory. Results also indicate that the increased interference from irrelevant negative material is associated with rumination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Memory for emotional trait adjectives in clinically depressed youth

An experiment was conducted to examine memory for emotional trait adjectives in depressed children and adolescents. Two groups of children and adolescents, clinically depressed participants and non-clinical controls, were compared on computerized versions of recall and recognition memory tasks. Three groups of words (positive trait adjectives, negative trait adjectives, and categorized neutral words) were used in the experiment. Results showed that the depressed group recalled significantly more negative adjectives than positive adjectives, whereas the control group recalled the same number of positive and negative adjectives. This effect was predicted by the association between age and level of depression, with the depression-related bias becoming stronger with age. Signal detection analysis revealed that the depressed group did not show any bias in the recognition task. The findings are discussed with respect to cognitive theories of depression with consideration of the developmental implications.     

Cognitive Processing of Emotional Information in Depression, Panic, and Somatoform Disorder.

Emotional Stroop tasks (subliminal/supraliminal exposures), implicit memory tasks (tachistoscopic word identification), and explicit memory tasks (free recall after incidental learning) with 4 word types (physical threat, positive, negative, and neutral words) were administered to patients with major depressive disorder (n = 30), panic disorder (n = 33), somatoform disorder (n = 25), and healthy control participants (n = 33). On the Stroop task, panic patients showed subliminal interferences for physical threat and negative words, depressive patients showed supraliminal interferences for negative words, and somatoform patients showed supraliminal interferences for physical threat words. No patient groups demonstrated implicit memory biases. On the explicit memory task, depressive and panic patients showed memory biases for negative words; somatoform patients showed biases for physical threat words. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit memory: Retention without remembering.

Explicit measures of human memory, such as recall or recognition, reflect conscious recollection of the past. Implicit tests of retention measure transfer (or priming) from past experience on tasks that do not require conscious recollection of recent experiences for their performance. The article reviews research on the relation between explicit and implicit memory. The evidence points to substantial differences between standard explicit and implicit tests, because many variables create dissociations between these tests. For example, although pictures are remembered better than words on explicit tests, words produce more priming than do pictures on several implicit tests. These dissociations may implicate different memory systems that subserve distinct memorial functions, but the present argument is that many dissociations can be understood by appealing to general principles that apply to both explicit and implicit tests. Phenomena studied under the rubric of implicit memory may have important implications in many other fields, including social cognition, problem solving, and cognitive development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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.     

Subliminal processing of emotional information in anxiety and depression.

Investigated selective processing of emotional information in anxiety and depression using a modified Stroop color naming task. 19 anxious, 18 depressed, and 18 normal control Ss were required to name the background colors of anxiety-related, depression-related, positive, categorized, and uncategorized neutral words. Half of the words were presented supraliminally, half subliminally. Anxious Ss, compared with depressed and normal Ss, showed relatively slower color naming for both supraliminal and subliminal negative words. The results suggest a preattentive processing bias for negative information in anxiety. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact perceptual and conceptual priming in temporal lobe epilepsy: Neuroanatomical and methodological implications.

Explicit memory appears to be supported by medical temporal lobe structures, whereas separate neocortical regions may mediate perceptual and conceptual implicit memory. Children and adults with temporal lobe epilepsy (TLE) and matched controls were administered experimental verbal memory tests. Performance on implicit tests--word identification and word generation--was contrasted with explicit recognition and recall. Encoding conditions emphasized either conceptual or perceptual aspects of study words and were crossed with presentation modality. The priming performance of participants with TLE did not differ from controls, but participants with TLE did show deficits on recognition and recall measures. Thus, intact left temporal cortex does not appear to be necessary for normal implicit memory performance, even when conceptual processing is emphasized at study or test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective valence and memory in depression: Dissociation of recall and fragment completion.

Depressed (n?=?16) and nondepressed (n?=?16) Ss' memory for affectively valenced words was assessed by an explicit test (free recall) and an implicit test (word fragment completion). Under free-recall instructions, depressed Ss recalled significantly more negatively valenced than positively valenced words, whereas the opposite pattern was observed in nondepressed control Ss. These results replicate those previously reported in the literature. The differential effect of word valence was absent, however, when memory was tested implicitly: Depressed and nondepressed Ss exhibited equivalent priming of positive and negative words. These data are discussed in terms of the J. M. Williams et al (1988) model of depression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are the memories of older adults positively biased?

There is disagreement in the literature about whether a "positivity effect" in memory performance exists in older adults. To assess the generalizability of the effect, the authors examined memory for autobiographical, picture, and word information in a group of younger (17-29 years old) and older (60-84 years old) adults. For the autobiographical memory task, the authors asked participants to produce 4 positive, 4 negative, and 4 neutral recent autobiographical memories and to recall these a week later. For the picture and word tasks, participants studied photos or words of different valences (positive, negative, neutral) and later remembered them on a free-recall test. The authors found significant correlations in memory performance, across task material, for recall of both positive and neutral valence autobiographical events, pictures, and words. When the authors examined accurate memories, they failed to find consistent evidence, across the different types of material, of a positivity effect in either age group. However, the false memory findings offer more consistent support for a positivity effect in older adults. During recall of all 3 types of material, older participants recalled more false positive than false negative memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Semantic Priming of Different Affective Categories.

The authors investigated affective semantic priming using a lexical decision task with 4 affective categories of related word pairs: neutral, happy, fearful, and sad. Results demonstrated a striking and reliable effect of affective category on semantic priming. Neutral and happy prime-targets yielded significant semantic priming. Fearful pairs showed no or modest priming facilitation, and sad primes slowed reactions to sad targets. A further experiment established that affective primes do not have generalized facilitatory-inhibitory effects. The results are interpreted as showing that the associative mechanisms that support semantic priming for neutral words are also shared by happy valence words but not for negative valence words. This may reflect increased vigilance necessary in adverse contexts or suggest that the associative mechanisms that bind negative valence words are distinct. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autobiographical memory style in seasonal affective disorder and its relationship to future symptom remission.

Autobiographical memory was examined in participants with seasonal affective disorder (SAD). In Experiment 1, participants with SAD performed an autobiographical memory task (AMT) in the winter when depressed. The AMT required participants to generate autobiographical memories to positive and negative cue words. Symptom levels were reassessed in the summer, when participants were remitted. The number of overly general memories to positive cues generated when the SAD participants were depressed predicted symptom levels when remitted, over and above initial symptom levels, with greater winter overgenerality being associated with high levels of summer symptoms. However, this was dependent on the exact measure of depressive symptoms used. The degree of overgenerality of memories in SAD participants was further investigated in Experiment 2. Results revealed that SAD participants did not show elevated recall of overgeneral memories relative to controls. The results as a whole indicate that, even when levels of general memories are no greater in a given target group than in controls, the absolute level of general memories to positive cues words is still independently related to symptom outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preserved word-stem-completion priming of semantically encoded information in Alzheimer's disease.

Alzheimer's disease (AD) patients and normal elderly control subjects completed 80 standardized sentence frames with single words, yielding a measure of semantic memory. Memory for best fit sentence endings was then tested either explicitly, with a forced-choice recognition task, or implicitly, with a word-stem-completion task. The patients completed fewer sentences with best fit word endings than did the control subjects. Explicit retention was markedly defective in the AD group, but word-stem completion was normal. The preserved word-stem completion in AD is discussed in terms of encoding operations and transfer-appropriate processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recognition bias for safe faces in panic disorder with agoraphobia

Panic patients with agoraphobia were compared with normal controls on tasks of face recognition. The subjects were presented with 20 photos, and were required to make a judgement of the persons on the photos; shortly afterwards they were unexpectedly presented with a recognition task. In the first study, one task was to judge whether the persons on the photos were critical or accepting: unlike social phobics (Lundh and Ost, 1996b, Behaviour Research and Therapy, 34, 787-794), panic patients showed no bias for critical vs accepting faces on the recognition task. In a secondary study, the task was to judge whether the persons on the photos were 'safe' or 'unsafe', i.e. whether they could be relied on if the subject would need help in some situation. The results showed a recognition bias for safe vs neutral faces in panic patients. The index of recognition bias for safe faces correlated with avoidance of feared situations when accompanied by others, as measured by the Mobility Inventory. The possibility that memory bias in emotional disorders is a function of basic concern, or functional importance, rather than positive/negative valence is discussed. The results are also discussed in terms of degree of elaboration, exposure duration of the stimuli, and the generality of the findings.     

Event-related potentials differentiate the effects of aging on word and nonword repetition in explicit and implicit memory tasks.

Explicit memory declines with age while implicit memory remains largely intact. These experiments extended behavioral findings by recording event-related potentials (ERPs) in young and elderly adults during repetition priming and recognition memory paradigms. Words and pronounceable nonwords repeated after 1 of 3 delays. Stimuli were categorized as either word-nonword or old-new. Repeated items elicited more positive-going potentials in both tasks. Hemispheric asymmetries for word and nonword processing were observed during lexical decision: Repetition effects were larger over the left hemisphere for words and over the right hemisphere for nonwords. For the young, ERP repetition effects were larger during recognition memory. For old adults, conversely, repetition produced more positive-going waveforms during lexical decision. The elderly had ERP and behavioral deficits at long recognition delays. ERP repetition effects in the elderly, like behavioral performance, were preserved in an implicit task but impaired in an explicit memory task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hemispheric perception of emotional valence from facial expressions.

The authors previously reported that normal subjects are better at discriminating happy from neutral faces when the happy face is located to the viewer's right of the neutral face; conversely, discrimination of sad from neutral faces is better when the sad face is shown to the left, supporting a role for the left hemisphere in processing positive valence and for the right hemisphere in processing negative valence. Here, the authors extend this same task to subjects with unilateral cerebral damage (31 right, 28 left). Subjects with right damage performed worse when discriminating sad faces shown on the left, consistent with the prior findings. However, subjects with either left or right damage actually performed superior to normal controls when discriminating happy faces shown on the left. The authors suggest that perception of negative valence relies preferentially on the right hemisphere, whereas perception of positive valence relies on both left and right hemispheres. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of valence on young and older adults’ attention in a rapid serial visual presentation task.

Using a rapid serial visual presentation task, the authors examined how the emotional valence of a word affected young and older adults’ abilities to detect another word that closely followed it in temporal proximity. Both age groups detected neutral words better when such words followed a positive or negative arousing word rather than a neutral arousing word. These results suggest that emotion influences attention in a similar fashion for young and older adults. Despite evidence that older adults can sometimes show a “positivity effect” in memory, we found no evidence of increased attention toward positive words for older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subjective qualities of memories associated with the picture superiority effect in schizophrenia.

Patients with schizophrenia (n=24) matched with 24 normal subjects were presented with both words and pictures. On a recognition memory task, they were asked to give remember, know, or guess responses to items that were recognized on the basis of conscious recollection, familiarity, or guessing, respectively. Compared with normal subjects, patients exhibited a lower picture superiority effect selectively related to remember responses. Unlike normal subjects, they did not exhibit any word superiority effect in relation to guess responses; this explains why the overall picture superiority effect appeared to be intact. These results emphasize the need to take into account the subjective states of awareness when analyzing memory impairments in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)