Increased novelty-induced grooming in aged rats: a preliminary observation

Age-related changes in grooming activity in female Fischer-344 rats were observed in a home cage and in a novel testing chamber for 50 min. Compared to the home cage condition with brief handling treatment, excessive grooming was found in the novel situation. The amount of novelty-induced grooming of aged rats (26-28 months) was about two times that of young animals (6-8 months). This increase in novelty-induced grooming of aged animals was attributable to an increase in the number of grooming bouts, prolongation of each grooming bout, and a slight increase in the duration of licking elements. However, there were no age differences in the percentage of face washing and the duration of face-washing elements. These results are discussed in terms of behavioral aging and age-related changes in peptidergic pathways in the brain.     

Postsurgical enrichment aids adult hemidecorticate rats on a spatial navigation task

The effect of environmental enrichment on normal rats, rats that received hemidecortication at birth, and rats that received hemidecortication when adult was studied in the Morris water task, which is a spatial navigation task requiring the use of distal cues for successful performance. Enrichment was achieved by housing the rats for 90 days in a large outdoor compound that was designed to model a natural environment. Adult hemidecorticated lab-raised rats were severely impaired in the acquisition of the task but neonatally hemidecorticated rats, although also impaired, showed significant sparing. Postsurgical, but not presurgical, enrichment of adult hemidecorticated rats significantly enhanced their recovery. Enrichment had little effect on neonatally decorticated rats or on normal rats. Although there were no gross anatomical changes associated with enrichment, the paradigm provides both a robust phenomena and a cortically dependent task that is ideal for investigating the processes in the remaining intact hemisphere that must support recovery.     

Age norms for impulsiveness,venturesomeness and empathy in children

A total of 1505 children (633 boys and 872 girls) completed the I₆ Impulsiveness Questionnaire. Reliabilities, scale intercorrelations and means and standard deviations are given after slight modifications were made to the original scoring key on the basis of factor analyses. Age means for both sexes are also given.     

A temperamental and development model for personality assessment: application to self-control in middle childhood

In personality theory and assessment, it is important to distinguish between dispositional and developmental constructs. This important but often neglected distinction is applied to general personality models, and, specifically, to psychological temperament dimensions and ego development. These conjoined domains are used as a framework to study impulsivity and self-control in a sample of middle-childhood boys. Impulsivity is conceptualized as a temperamental dimension and self-control as an ego-developmental dimension. A factor-analytic procedure was used to test the assumption of orthogonality between impulsivity and self-control. Results were consistent with the hypothesis and provide implications for the concept of ‘difficulty’ of temperament constellations and study of ego development in middle childhood.     

Interrogative suggestibility and delinquent boys: An empirical validation study

This study has several aims. First, to validate the Gudjonsson Suggestibility Scale (GSS) among delinquent and adolescent boys placed in an assessment and short-term treatment centre. Second, to test the hypothesis that adolescent boys are particularly susceptible to suggestions when they are ‘pressured’ by negative feedback and instructions. Finally, to investigate the hypothesis that suggestibility is related to memory recall and self-esteem. The GSS was administered to 31 boys (ages 11 to 16 yr) who had been independently rated by two teachers on measures of suggestibility and self-esteem. Suggestibility as measured by the GSS was found to correlate significantly with the teachers' ratings of suggestibility, supporting empirically the criterion-related validity of the GSS. Compared with young ‘normal’ adults the boys were no more likely to give in to suggestive questions than the adults, unless their performance was subjected to criticism and negative feedback. The results suggest that deliquent adolescents may be particularly responsive to interpersonal pressure during interrogation. The findings have important implications for police interrogation procedures.     

Development of differences in response latencies to right and left visual fields

Robust lateralization developed in right-handed adults who were asked to judge letter pairs as "same" or "different" during 4608 trials. By the end of the first two blocks (768 trials) "same" responses were favored when presented in the RVF (transmitted directly to the left hemisphere) and "different" responses were favored when presented in the LVF (transmitted direction to the right hemisphere). This gradually reversed over sessions with "same" responses becoming faster for letters presented in the LVF, and "different" responses becoming faster for stimuli presented in the RVF. The laterality acquired under these conditions was cumulative and reproducible, appeared in all 16 subjects, and was preserved between sessions a week apart. The data suggest that laterality is a flexible and reversible characteristic of the human brain even when stimulus and task remain constant.     

Effects of perceptual and conceptual similarity in semantic priming

Summary The study investigates the different contributions to semantic priming of two components of the semantic representation underlying a word. The two components are perceptually based information and conceptually based information. Perceptual information is based on physical attributes such as shape or color, while conceptual information consists of more abstract elements such as functional attributes. The question asked in this study was whether both components would produce an effect in semantic priming. Pairs of words either related because of a conceptual property (banana-apple), a perceptual property (ball-apple), or both because of a perceptual and conceptual property (cherry-apple) were presented as prime and target in a lexical decision and a word-naming task. The results showed independent contributions of perceptual and conceptual attributes to semantic priming.This research was supported by a grant from the Dutch Organization for the Advancement of Pure Research (ZWO). All three authors are senior authors and have contributed to all parts of the project.     

The direct effects of compliance on health outcome

Six studies that randomized patients to drugs versus placebo and also made complaint/noncompliant determinations were reviewed to document the main effects of compliance on health outcome. While the studies varied in terms of demonstrating a main effect of drugs, in five of six cases a main statistical effect of compliance was observed. Possible mechanisms for this effect are briefly noted.     

Detection versus discrimination of visual orientation

The role of focused attention in vision is examined. Recent theories of attention hypothesize that serial search by focal attention is required for discrimination between different combinations of features. Experiments are reported which show that the mixture of a few (less than five) horizontal and vertical line segments embedded in an aggregate of diagonal line segments can be rapidly counted (also called 'subitizing') by a parallel (preattentive) process, while the discrimination between horizontal and vertical orientation requires serial search by shifting focal attention to each line segment. Thus detecting and counting targets that differ in orientation can be done in parallel by a preattentive process, whereas knowing 'what' the orientation of a target is (horizontal or vertical, ie of a single conspicuous feature) requires a serial search by focal attention.     

The influence of information redundancy upon the use of traits and persons as organizing categories

The following question is addressed: How do multiple, simultaneously present cognitive structures influence the representation and recall of social information? In an empirical study examining both free and cued recall, we found the variable information redundancy to influence both the organization and accuracy of subjects' recollections of trait-related behaviors. Redundancy was defined in terms of the degree of person/trait overlap in a social information ensemble. Some evidence indicated that this effect is attributable to an increase in the discriminability of the organizational structures during encoding. The implications of these findings for understanding the formation of integrated cognitive representations of individuals and the spontaneous use of traits in social information processing are discussed.