Attention effects during visual short-term memory maintenance: protection or prioritization?

Interactions between visual attention and visual short-term memory (VSTM) play a central role in cognitive processing. For example, attention can assist in selectively encoding items into visual memory. Attention appears to be able to influence items already stored in visual memory, as well; cues that appear long after the presentation of an array of objects can affect memory for those objects (Griffin & Nobre, 2003). In five experiments, we distinguished two possible mechanisms for the effects of cues on items currently stored in VSTM. A protection account proposes that attention protects the cued item from becoming degraded during the retention interval. By contrast, aprioritization account suggests that attention increases a cued item's priority during the comparison process that occurs when memory is tested. The results of the experiments were consistent with the first of these possibilities, suggesting that attention can serve to protect VSTM representations while they are being maintained.     

Unconscious, stimulus-dependent priming and conscious, percept-dependent priming with chromatic stimuli

Using metacontrast masking to suppress the conscious registration of a prime stimulus, Breitmeyer, Ro, and Singhal (2004) showed that color priming produced by a masked prime disk occurs at unconscious stimulus-dependent rather than at percept-dependent levels of visual processing. The current set of experiments compares this type of unconscious stimulus-dependent priming to conscious priming produced by a prime that, in two separate ways, is rendered visible and thus activates percept-dependent visual processes. The results indicate that while the masked prime again acts at a stimulus-dependent level of processing, the unmasked, visible primes additionally act at a later percept-dependent level of processing.     

The cross-category effect: mere social categorization is sufficient to elicit an own-group bias in face recognition

Although the cross-race effect (CRE) is a well-established phenomenon, both perceptual-expertise and social-categorization models have been proposed to explain the effect. The two studies reported here investigated the extent to which categorizing other people as in-group versus out-group members is sufficient to elicit a pattern of face recognition analogous to that of the CRE, even when perceptual expertise with the stimuli is held constant. In Study 1, targets were categorized as members of real-life in-groups and out-groups (based on university affiliation), whereas in Study 2, targets were categorized into experimentally created minimal groups. In both studies, recognition performance was better for targets categorized as in-group members, despite the fact that perceptual expertise was equivalent for in-group and out-group faces. These results suggest that social-cognitive mechanisms of in-group and out-group categorization are sufficient to elicit performance differences for in-group and out-group face recognition.     

Neurocognitive Effects of Methamphetamine: A Critical Review and Meta-analysis

This review provides a critical analysis of the central nervous system effects of acute and chronic methamphetamine (MA) use, which is linked to numerous adverse psychosocial, neuropsychiatric, and medical problems. A meta-analysis of the neuropsychological effects of MA abuse/dependence revealed broadly medium effect sizes, showing deficits in episodic memory, executive functions, information processing speed, motor skills, language, and visuoconstructional abilities. The neuropsychological deficits associated with MA abuse/dependence are interpreted with regard to their possible neural mechanisms, most notably MA-associated frontostriatal neurotoxicity. In addition, potential explanatory factors are considered, including demographics (e.g., gender), MA use characteristics (e.g., duration of abstinence), and the influence of common psychiatric (e.g., other substance-related disorders) and neuromedical (e.g., HIV infection) comorbidities. Finally, these findings are discussed with respect to their potential contribution to the clinical management of persons with MA abuse/dependence.     

Coping styles and personality: a biometric analysis

Previous research suggests that coping styles are modestly heritable and that this genetic influence is shared in large part with genetic influences on personality. To test this hypothesis, we estimated the heritable basis of the Coping Inventory for Stressful Situations in a sample of 91 monozygotic and 80 dizygotic twin pairs. Task-oriented, emotion-oriented, and social diversion coping styles were modestly heritable (h(2)=.17 to .20), whereas the use of distraction appeared to be influenced solely by environmental factors. Multivariate analyses showed that genetic contributions to coping styles were, at best, only modestly related to genetic contributions to personality (r=-.03 to .35). Environmental contributions to personality were unrelated to environmental factors in coping style. These results suggest that coping style is not merely a manifestation of basic personality traits but does support the possibility that the genetic factors in personality influences have a modest influence on an individual's preferred coping style or strength (e.g., rigidity vs flexibility).     

Psychological factors and use of antiepileptic drugs: pilot work using an objective measure of adherence

Given the current emphasis on the "concordance" prescribing model, a study was designed to determine the influence of patients' beliefs about epilepsy, beliefs about medication and a range of neuroepilepsy variables on drug adherence among a sample of epilepsy patients. A special feature of the study was the use of a credible objective measure of drug adherence. Psychological health was also assessed. Thirty-seven patients were recruited from a local epilepsy clinic. Beliefs about epilepsy (illness representations), beliefs about epilepsy medication, anxiety, depression, neuroepilepsy status and adherence were all measured. Data were collected via clinical interview and questionnaire methods. Adherence with drug treatment was determined by an objective measure using low-dose phenobarbital as an indicator of adherence and, or, measurement of antiepileptic drug levels. Neither illness representations nor beliefs about epilepsy drugs were related to adherence. With the exception of time since last seizure, which was positively related to adherence, neuroepilepsy variables were unrelated to adherence. A number of significant associations between cognitive representations of epilepsy and mood were found.     

Distortions in the memory of the pitch of speech

Corneille, Huart, Becquart, & Brédart (2004) found that people remember ambiguous race faces as closer to a race prototype than they actually are. In three studies, we examined whether this memory bias generalizes to voice memory. In Studies 1 and 2, participants listened to synthesized male and female speech samples (high, moderate, or low pitch) and were asked to identify a voice target when paired against distracters higher or lower in pitch. The results showed that pitch distortions occurred, with the pattern consistent with assimilation toward low and high ends of the pitch continuum. Study 3 replicated this result with a wider voice pitch range. The results parallel those of Corneille et al. (2004). The implications of this work are discussed.     

A conjunctive feature similarity effect for visual search

Traditional models of visual search assume interitem similarity effects arise from within each feature dimension independently of other dimensions. In the present study, we examine whether distractor-distractor effects also depend on feature conjunctions (i.e., whether feature conjunctions form a separate “feature” dimension that influences interitem similarity). Spatial frequency and orientation feature dimensions were used to generate distractors. In the bound condition, the number of distractors sharing the same conjunction of features was higher than that in the unbound condition, but the sharing of features within frequency and orientation dimensions was the same across conditions. The results showed that the target was found more efficiently in the bound than in the unbound condition, indicating that distractor-distractor similarity is also influenced by conjunctive representations.