Environmental enrichment results in cortical and subcortical changes in levels of synaptophysin and PSD-95 proteins

Experience-dependent plasticity is thought to involve selective change in pre-existing brain circuits, involving synaptic plasticity. One model for looking at experience-dependent plasticity is environmental enrichment (EE), where animals are exposed to a complex novel environment. Previous studies using electron microscopy showed that EE resulted in synaptic plasticity in the visual cortex and hippocampus. However, the areas in the brain that have been examined following EE have been limited. The present study quantified potential synaptic plasticity throughout the brains of C57BL/6 mice using an enzyme-linked immunosorbent assay (ELISA) for two synaptic proteins, synaptophysin and PSD-95. EE resulted in increased synaptophysin and PSD-95 levels through major brain regions, including anterior and posterior areas of the forebrain, hippocampus, thalamus, and hypothalamus. However, no changes in synaptophysin were detected in the cerebellum. These results demonstrate that EE results in an increase in levels of both pre- and post-synaptic proteins in multiple regions of the brain, and it is possible that such changes represent the underlying synaptic plasticity occurring in EE.     

Influence analysis of structural equation models with polytomous variables

The estimation of model parameters in structural equation models with polytomous variables can be handled by several computationally efficient procedures. However, sensitivity or influence analysis of the model is not well studied. We demonstrate that the existing influence analysis methods for contingency tables or for normal theory structural equation models cannot be applied directly to structural equation models with polytomous variables; and we develop appropriate procedures based on the local influence approach of Cook (1986). The proposed procedures are computationally efficient, the necessary bits of the proposed diagnostic measures are readily available following an usual fit of the model. We consider the influence of an individual cell frequency with respect to three cases: when all parameters in an unstructured model are of interest, when the unstructured polychoric correlations are of interest, and when the structural parameters are of interest. We also consider the sensitivity of the parameters estimates. Two examples based on real data are presented for illustration.The work described in this paper was partially supported by a Chinese University of Hong Kong Postdoctoral Fellows Scheme and a grant from the Research Grants Council of the Hong Kong Special Administrative Region, China (RGC Ref. No. CUHK4186/98P). We are indebted to P.M. Bentler and M.D. Newcomb for providing the data set, Michael Leung for his assistance, and the Editor and the referees for some very valuable comments.     

Reinvigorating the Study of Careers

Before discussing how to innovate the study of career development using insights from life-span psychology and life course sociology, researchers might benefit from reconsidering whether they are studying careers or studying vocational behavior. While the word “career” seems ubiquitous in vocational psychology research, there are important differences between the study of vocational behavior, occupational roles, and career development. In this article, I urge researchers to (a) reconsider the meaning of career and research on career development, (b) adopt prospective, longitudinal research designs, and (c) concentrate first on processes of development and then on the content of careers. Considering these suggestions may ready vocational psychology for true innovations such as studying human development through work and relationships.     

Self-Presentation Concerns and Health Behaviors Among Cosmetic Surgery Patients

The present investigation examined the relationship between self-presentational motives and physical activity in a population of cosmetic surgery participants. Participants were 50 female and 5 male cosmetic surgery patients (CSPs; M age = 38.5 years) who completed a battery of self-report measures following either vein or acne treatment. Analyses revealed significant group differences on self-presentational concern and public self-consciousness between: (a) those who elected the treatment for appearance motives and those who elected treatment for health-based motives, and (b) the more frequent (3 or more times per week) and less frequent (2 or less times per week) exercisers. Greater self-presentational concerns and greater public self-consciousness were associated with having appearance-related motives for treatment and with being a less frequent exerciser.     

The Role of Prototypical Situations in the Perceptions of Prejudice of African Americans1

Inman and Baron (1996) found that African Americans and Whites possess prototypes for racist behavior that involve Whites oppressing African Americans. However, prototypical content may be more detailed and specific for African Americans because of differing cultural experiences. In the present experiment, undergraduates read stories about interpersonal encounters representing prototypical and nonprototypical situations. Actor race ambiguity was manipulated by the presence or absence of photographs. As expected, Whites tended to make equal ratings of prejudiced behavior for prototypical and nonprototypical situations. However, African Americans perceived more prejudice in prototypical vignettes than in nonprototypical vignettes. They also perceived stronger prejudicial displays and more dispositional motivation for targets in prototypical vignettes. The results suggest that African Americans have heightened sensitivity to prejudice in specific situations, a factor that may contribute to racial confrontations and misunderstandings.     

Inducing Hypocrisy to Reduce Prejudicial Responses among Aversive Racists

Might a hypocrisy induction procedure reduce prejudicial behavior among aversive racists? We identified aversive racists as individuals low in explicit prejudice but high in implicit prejudice toward Asians. Results revealed that aversive racists, but not truly low prejudiced participants (i.e., those low in both explicit and implicit prejudice), responded to a hypocrisy induction procedure with increased feelings of guilt and discomfort, compared to those in a control condition. Furthermore, aversive racists, but not low prejudiced participants, responded to a hypocrisy induction procedure with a reduction in prejudicial behavior. These results suggest that consciousness raising might play an important role in motivating aversive racists to reduce their prejudicial behavior.