DOUBLE DISSOCIATION BETWEEN MEMORY SYSTEMS UNDERLYING EXPLICIT AND IMPLICIT MEMORY IN THE HUMAN BRAIN

Abstract— Amnesic patients have impaired explicit memory that is evident in poor recall and recognition of words, yet can have intact implicit memory for words as measured by repetition priming, the enhanced efficiency for reprocessing those word's. The dissociation between explicit and implicit memory for words is a fundamental characteristic of normal cognition that could reflect two different functional architectures of the human brain two separate processing systems or two levels of operation of a single system with implicit memory less demanding of that system. We present a patient who has a lesion in the right occipital lobe and who showed intact explicit and impaired implicit memory for words. The deficit was specific to visual priming. The double dissociation between explicit and implicit visual memory for words indicates that separate processing systems mediate these two forms of memory, and that a memory system in right occipital cortex mediates implicit visual memory for words.     

Trade-offs, individual differences, and misunderstandings about evolutionary psychology

Replies to comments on Evolutionary psychology: Controversies, questions, prospects, and limitations (see record 2010-02208-001) by Confer et al. The purpose of which was to clarify the logic of evolutionary psychology and clear up some of the more common misunderstandings about it. In this response, we address the key points raised by the commentators.     

Decomposing coronary-prone behavior: Dimensions of type a behavior in the Videotaped Structured Interview

This study examined the factorial structure of data generated in the Videotaped Structured Interview for assessment of Type A behavior. Based on the literature, it was argued that there are at least three distinct concepts of Type A behavior, focused on competitiveness and pressured drive, speech characteristics, and hostility, respectively. These three concepts were clearly represented among the factors from factor analyses based on data from 282 subjects. Three factors represented speech and psychomotor characteristics, where the first reflected interactions between subject and interviewer (e.g., response latency, interruptions), the second tempo of speech (accelerating, dysrhythmic and rapid speech), and the third oral gestures (e.g., expiratory sighs). Hostility was reflected in two factors, one defined by emotional intensity (e.g., anger when recalling paat event) and the other hostility expressed towards the interviewer. Pressured drive dominated a content factor reflecting self-awareness of Type A behavior. Finally, there was one factor related to psychomotor tension. Through further factor and item analyses, it was possible to combine these factors into three homogeneous and moderately intercorrelated subscales of Type A behavior reflecting Hostility, Speech Characteristics, and Self-Awareness of Type A behavior. These scales showed good interrater agreement and stability over two years. The Self-Awareness Scale was highly correlated with self-report measures of Type A behavior. The Hostility Scale, on the other hand, was moderately related to measures of Type A behavior, anger and hostility, but was unrelated to anxiety. The Speech Characteristic Scale, finally, was virtually unrelated to psychometric measures.     

Permanence and change in memory II. Reproduction of words in sentences

Abstract.— A retroactive interference paradigm was employed for studying qualitative memory changes. Sentences, containing an ambiguous word that was defined differently by succeeding words, were used as stimulus material. Such retroactive definitions of meaning were found to lead to qualitative changes in reproduction. It is suggested that the issue of permanence and change in memory may be related to the choice of lists of independent items or contextual units as stimulus material. A contextual theory of memory, implying the conception of memory in a stream, is advocated.     

A longitudinal study of implicit and explicit memory in old persons

Decline in explicit memory with advancing age is a common finding, but it is unclear whether implicit memory (repetition priming) declines or remains stable. Meta-analyses of studies that examined differences between extreme groups (young-old), typically at a single point in time and on a single test, suggest that a mild reduction in priming occurs with advancing age. The authors examined explicit memory and priming, on multiple tests over 4 annual data-collection waves, in a large group of older persons without dementia at baseline. Explicit memory declined significantly, but priming remained stable. Findings indicate that explicit memory and priming are dissociable on the basis of age-related change and that mildly reduced priming is not an inevitable consequence of growing older.     

Convergent behavioral and neuropsychological evidence for a distinction between identification and production forms of repetition priming

Four experiments examined a distinction between kinds of repetition priming which involve either the identification of the form or meaning of a stimulus or the production of a response on the basis of a cue. Patients with Alzheimer's disease had intact priming on picture-naming and category-exemplar identification tasks and impaired priming on word-stem completion and category-exemplar production tasks. Division of study-phase attention in healthy participants reduced priming on word-stem completion and category-exemplar production tasks but not on picture-naming and category-exemplar identification tasks. The parallel dissociations in normal and abnormal memory cannot be explained by implicit-explicit or perceptual-conceptual distinctions but are explained by an identification-production distinction. There may be separable cognitive and neural bases for implicit modulation of identification and production forms of knowledge.     

How Discrimination Impacts Sociopolitical Behavior: A Multidimensional Perspective

The conventional wisdom regarding the impact of discrimination on political behavior is that the perception of prejudiced treatment motivates individuals to take political action. This study challenges this common conception by demonstrating that the source of discrimination can play a significant role in whether perceived or experienced injustice leads to activism or withdrawal from sociopolitical life. Drawing from political science and social psychology literature, this study provides a new perspective on the potential effects of discrimination on a relatively new marginalized group in the United States. Specifically, an important distinction is drawn between political (systematic) and societal (interpersonal) discrimination in analyzing the sociopolitical behavior of American Muslims in the aftermath of the 9/11 terrorist attacks. The results will hopefully encourage scholars to take a deeper look at the nexus between discrimination and democratic engagement, which is an important, complex, multidimensional, and understudied topic.