Further analysis of encoding in patients with Huntington's disease

Arguments favoring the view that derangement of normal encoding processes contributes to the memory defects of patients with Huntington's disease (HD) are supported by the finding that HD patients do not learn highly imageable words more rapidly than they learn words that are difficult to image. But other data indicating that HD patients can use verbal mediators as mnemonic aids for picture recognition question the existence of important and general encoding deficits in HD. In the first of two experiments the influence of imagery on the acquisition and recall of 14-word lists was studied using a free-recall paradigm. Both HD patients and controls learned highly imageable words more quickly and retained them better than low imagery words over a 30-min delay. The impact of imagery on learning was apparent by the first trial. In the second experiment, a modified Brown-Peterson distractor paradigm was used to assess release from proactive interference (PI). It was found that both HD patients and controls exhibited comparable release from PI following a shift in taxonomic categories. The results of both experiments question the importance of encoding deficits in the memorial dysfunctions associated with HD.     

Reviews of current books

Pastoral Psychology -     

The detection and treatment of artifacts in computer-controlled neurophysiological experiments

Pattern recognition algorithms may be employed on time-series data obtained in electrophysiological experiments to detect particular artifacts that would otherwise contaminate the experimental data. Such algorithms may be classified by the statistical properties of the data they test. Four representative algorithms are presented that, on the basis of prior experiments in our laboratory, perform satisfactorily to improve the quality of electrophysiological measurement.     

Gender differences in geographical knowledge

In five experiments involving more than 1800 undergraduate students, males more accurately located places on maps of the United States or its various regions than did females. These gender differences could not be attributed to education, travel history, desire to travel, or in the amount of incidental exposure to several potential sources of geographic information in everyday life. Males performed more accurately than females on measures of egocentric and allocentric spatial orientation, but performance on these tasks was only weakly predictive of accuracy on tests of geographical knowledge. Since males and females learned the locations of places on an unfamiliar map at similar rates, regardless of whether such learning occurred under intentional or incidental instructions, gender differences in geographical knowledge cannot be attributed to differences in capacity to learn place locations on maps. An attentional hypothesis is proposed to account for the more accurate performance of males on tests of geographical knowledge.     

Spatial memory in rats: electroconvulsive shock selectively disrupts working memory but spares reference memory

In two experiments rats were trained until they displayed highly accurate spatial memories when a 4-h delay was imposed between the to-be-remembered event (TBRE) and the retention test in a 12-arm radial maze. If the procedure tested only working memory (WM) electronvulsive shock (ECS) 2 h after the TBRE produced amnesia but ECS immediately after the TBRE was ineffective. If the testing procedure also involved a reference memory (RM) component, ECS degraded WM regardless of whether it was given 0 or 2 h after the TBRE. RM was not affected. With either training procedure administering ECS 2 h before the TBRE was ineffective. Thus, in the radial maze truly old spatial RM was immune to disruption by ECS while more recent WM was vulnerable. Possible explanations of the data are presented.     

Two Studies Examining the Error Theory Underlying the Measurement Model of the Verbal Aggressiveness Scale

Meta‐analysis indicates moderate correlations between the Verbal Aggressiveness Scale (VAS) and other self‐report measures but near‐zero correlations with behavioral measures. Accurately interpreting correlations between the VAS and other variables, however, requires an examination of the untested error theory underlying the measurement model for the VAS. In two separate studies, the results of single‐factor correlated uniqueness confirmatory factor analytic models revealed a pattern of significant error covariances indicating that VAS item scores are confounded by systematic error attributable to multiple unspecified latent effects. After pruning the item sets, we identified 4 items that were free of latent variable influences other than trait verbal aggressiveness. Implications for interpreting the verbal aggressiveness literature are discussed along with recommendations for revising the VAS.     

Seeing minds in others: Mind perception modulates low-level social-cognitive performance and relates to ventromedial prefrontal structures

In social interactions, we rely on nonverbal cues like gaze direction to understand the behavior of others. How we react to these cues is affected by whether they are believed to originate from an entity with a mind, capable of having internal states (i.e., mind perception). While prior work has established a set of neural regions linked to social-cognitive processes like mind perception, the degree to which activation within this network relates to performance in subsequent social-cognitive tasks remains unclear. In the current study, participants performed a mind perception task (i.e., judging the likelihood that faces, varying in physical human-likeness, have internal states) while event-related fMRI was collected. Afterwards, participants performed a social attention task outside the scanner, during which they were cued by the gaze of the same faces that they previously judged within the mind perception task. Parametric analyses of the fMRI data revealed that activity within ventromedial prefrontal cortex (vmPFC) was related to both mind ratings inside the scanner and gaze-cueing performance outside the scanner. In addition, other social brain regions were related to gaze-cueing performance, including frontal areas like the left insula, dorsolateral prefrontal cortex, and inferior frontal gyrus, as well as temporal areas like the left temporo-parietal junction and bilateral temporal gyri. The findings suggest that functions subserved by the vmPFC are relevant to both mind perception and social attention, implicating a role of vmPFC in the top-down modulation of low-level social-cognitive processes.