Neural markers of categorization in 6-month-old infants

Little is known of the neural processes that underlie concept-formation abilities in human infants. We investigated category-learning processes in infants both by using a common behavioral measure and by recording the brain's electrical activity (event-related potentials, or ERPs). ERPs were recorded while 6-month-olds viewed cat images during training, followed by novel cat images interspersed with novel dog images during test. The data indicate that distinct neural signals correspond with learning of a category presented during familiarization, preferential responding to a novel category, and representation of category exemplars at multiple levels of inclusiveness. The results suggest that fundamental components of the neural architecture supporting object categorization are functional within the first half-year of postnatal life, before infants acquire language and young children engage in formal learning of semantic categories. The findings are discussed in terms of their implications for models of category learning and development.     

The distinctiveness of the word-length effect

The authors report 2 experiments that compare the serial recall of pure lists of long words, pure lists of short words, and lists of long or short words containing just a single isolated word of a different length. In both experiments for pure lists, there was a substantial recall advantage for short words; the isolated words were recalled better than other words in the same list, and there was a reverse word-length effect: Isolated long words were recalled better than isolated short words. These results contradict models that seek to explain the word-length effect in terms of list-based accounts of rehearsal speed or in terms of item-based effects (such as difficulty of assembling items).     

Comparison of factor structure models for the Beck Depression Inventory--II

Factor analyses of the Beck Depression Inventory--II (A. T. Beck, R. A. Steer, & G. K. Brown, 1996) have frequently produced 2 different 2-factor oblique structures. The author used confirmatory factor analyses to compare these structures with a general-factor model with 2 orthogonal group factors. The general-factor model fit as well as or better than the 2-factor models when applied to item data from previous studies (3 clinical and 2 college samples). Communalities associated with the General Depression factor ranged from 71% to 82%. Cognitive and Somatic group factors were indicative of intropunitiveness and fatigue. It was concluded that the general-factor model gives an acceptable empirical explanation of item covariance structure and offers a conceptual interpretation that is well suited to clinical practice and research.     

Self-control and tool use in tufted capuchin monkeys (Cebus apella)

Self-control is defined as forgoing immediate gratification to obtain a greater reward. Tool use may relate to self-control because both behaviors may require foresight and deliberate control over one's actions. The authors assessed 20 capuchin monkeys (Cebus apella) for the ability to delay gratification in a tool task. Subjects were given rod-shaped food items that could either be consumed immediately or be carried to an apparatus and used to extract a more preferred food. The authors found that some monkeys were able to exhibit self-control. Monkeys with relatively more tool use experience demonstrated the greatest levels of self-control. These results indicate that capuchins are capable of delaying gratification when a higher quality reinforcer is present and that tool experience can influence levels of self-control in this task.     

HIV-1 encephalopathy among perinatally infected children: Neuropathogenesis and response to highly active antiretroviral therapy

HIV-1 encephalopathy among perinatally infected children in the United States was initially defined by a classic triad of findings that included: (1) developmental delay, (2) secondary or acquired microcephaly, and (3) pyramidal tract neuromotor deficits. The most severe form of this disorder typically occurred among young children who developed rapidly progressive disease in concert with profound immunosuppression, and Pneumocystis jiroveci pneumonitis (PCP). The neuropathogenesis of this disorder appears to involve a cascade of viral products, various cytokines and chemokines, and neurotransmitters which promote ongoing inflammation, excitation, and overstimualtion of the N-methyl-D-aspartate type receptor (NMDAR) system. These subsequently lead to neuronal injury and death secondary to apoptosis or necrosis, astrocytosis, as well as dentritic and synaptic damage. The frequency of the most severe forms of encephalopathy among children has dropped dramatically since the introduction of highly active antiretroviral therapy (HAART). Of concern, however, is the possibility that a more insidious form of this disorder may be occurring presently among older vertically infected children as a result of inadequate penetration of HAART agents into the cerebrospinal fluid (CSF). This paper will review what published data there is as yet that bears on this question.     

Assessing family-of-origin functioning in Mexican American adults: retrospective application of the family environment scale

Although both theoretical and empirical literature suggests that individuals' family-of-origin experiences affect subsequent relationship functioning as adults, few studies have examined the appropriateness of family assessment techniques when applied retrospectively for use in either theory development or clinical applications. This study examined psycho-metric characteristics of the Family Environment Scale (FES) when used retrospectively with Mexican Americans to assess their families-of-origin. Findings provided qualified support for the internal consistency of the FES and showed significant mean profile differences for this population across gender and when compared to the normative sample for this measure. Retrospective reports on the FES related to independent measures of family history of distress and, to a lesser extent, with current relationship functioning, providing preliminary support for the criterion-related validity of the FES when adapted for retrospective assessment. Limitations and implications of findings for further research are discussed.     

Intention in motor learning through observation

The purpose of this experiment was to assess whether learning an action through observation is enhanced by the intention to reproduce the observed behaviour. Two groups of participants observed a model practise a timing task and performed a 24-hour delayed retention test. Participants in the first group of observers were explicitly instructed that they would be required to execute the timing task that they had observed as accurately as possible during the delayed retention test. Observers in the second group were instructed that they would be required to describe as accurately as possible the behaviour that they had observed. A control group of participants, who did not observe the model, was also administered the delayed retention test. The results of the retention test indicated that absolute timing (parameterization) was learned by the observers to the same extent with or without intention to reproduce the task. Indeed, on the retention test absolute timing for the two groups of observers was as effective as that for the models. However, observing with an intention to reproduce the task was beneficial for learning the movement's relative timing structure. Results are discussed with respect to a potential mechanism by which intention enhances observation.     

Social cognitive theory of posttraumatic recovery: the role of perceived self-efficacy

The present article integrates findings from diverse studies on the generalized role of perceived coping self-efficacy in recovery from different types of traumatic experiences. They include natural disasters, technological catastrophes, terrorist attacks, military combat, and sexual and criminal assaults. The various studies apply multiple controls for diverse sets of potential contributors to posttraumatic recovery. In these different multivariate analyses, perceived coping self-efficacy emerges as a focal mediator of posttraumatic recovery. Verification of its independent contribution to posttraumatic recovery across a wide range of traumas lends support to the centrality of the enabling and protective function of belief in one's capability to exercise some measure of control over traumatic adversity.