Adolescent personality: a five-factor model construct validation

The purpose of this study was to investigate convergent and discriminant validity of the five-factor model of adolescent personality in a school setting using three different raters (methods): self-ratings, peer ratings, and teacher ratings. The authors investigated validity through a multitrait-multimethod matrix and a confirmatory factor analysis correlated trait, uncorrelated method model. With the exception of Emotional Stability, each analysis demonstrated similar patterns and together provided support for the convergent and discriminant validity of the five-factor model structure of adolescent personality. However, among the three raters, self-ratings of personality provided a comparatively weaker method for assessing adolescent personality. The influences of agreement between self and other raters are discussed in relation to contrast, perceiver, and target effects; expert observer effects; the degree of acquaintanceship; and the effect of the social context.     

Combining probability values from independent permutation tests: a discrete analog of Fisher's classical method

Permutation tests are based on all possible arrangements of observed data sets. Consequently, such tests yield exact probability values obtained from discrete probability distributions. An exact nondirectional method to combine independent probability values that obey discrete probability distributions is introduced. The exact method is the discrete analog to Fisher's classical method for combining probability values from independent continuous probability distributions. If the combination of probability values includes even one probability value that obeys a sparse discrete probability distribution, then Fisher's classical method may be grossly inadequate.     

Secure and defensive high self-esteem

Long-standing theories have suggested high self-esteem (SE) can assume qualitatively different forms that are related to defensiveness. The authors explored whether some high-SE individuals are particularly defensive because they harbor negative self-feelings at less conscious levels, indicated by low implicit SE. In Study 1, participants high in explicit SE but low in implicit SE showed the highest levels of narcissism--an indicator of defensiveness. In Studies 2 and 3, the correspondence between implicit and explicit SE predicted defensive behavior (in-group bias in Study 2 and dissonance reduction in Study 3), such that for high explicit-SE participants, those with relatively low implicit SE behaved more defensively. These results are consistent with the idea that high SE can be relatively secure or defensive.     

Long-term memory survives nerve injury and the subsequent regeneration process

A three-neuron network (a central pattern generator [CPG]) is both sufficient and necessary to generate aerial respiratory behavior in the pond snail, Lymnaea stagnalis. Aerial respiratory behavior is abolished following a specific nerve crush that results in axotomy to one of the three CPG neurons, RPeD1. Functional regeneration of the crushed neurite occurs within 10 days, allowing aerial respiratory behavior to be restored. Functional regeneration does not occur if the connective is cut rather than crushed. In unaxotomized snails, aerial respiratory behavior can be operantly conditioned, and following memory consolidation, long-term memory (LTM) persists for at least 2 weeks. We used the Lymnaea model system to determine (1) If in naive animals axotomy and the subsequent regeneration result in a nervous system that is competent to mediate associative learning and LTM, and (2) if LTM survives RPeD1 axotomy and the subsequent regenerative process. We show here that (1) A regenerated nervous system is competent to mediate associative memory and LTM, and (2) LTM survives axotomy and the subsequent regenerative process.     

Cell phone-induced failures of visual attention during simulated driving

This research examined the effects of hands-free cell phone conversations on simulated driving. The authors found that these conversations impaired driver's reactions to vehicles braking in front of them. The authors assessed whether this impairment could be attributed to a withdrawal of attention from the visual scene, yielding a form of inattention blindness. Cell phone conversations impaired explicit recognition memory for roadside billboards. Eye-tracking data indicated that this was due to reduced attention to foveal information. This interpretation was bolstered by data showing that cell phone conversations impaired implicit perceptual memory for items presented at fixation. The data suggest that the impairment of driving performance produced by cell phone conversations is mediated, at least in part, by reduced attention to visual inputs.     

How golden hamsters (Mesocricetus auratus) discriminate top from bottom flank scents in over-marks

Using a habituation-discrimination paradigm, the authors investigated what cues male golden hamsters (Mesocricetus auratus) use to determine the top and bottom positions in flank gland over-marks. A difference in the ages of 2 hamsters' marks did not, by itself, produce differential memory or evaluation of the 2 scents. A spatial configuration of marks suggestive of an overlap was sufficient for the apparently overlapping scent to be remembered or valued more than the apparently underlying scent. Cues from the overlap of 2 hamsters' marks were also sufficient. These results, consistent with those previously found for responses to hamster vaginal scent over-marks, suggest that hamsters use similar cues to analyze scent over-marks that are different in chemical composition and in social functions.     

Correlations for timing consistency among tapping and drawing tasks: evidence against a single timing process for motor control.

Three experiments were conducted to examine whether timing processes can be shared by continuous tapping and drawing tasks. In all 3 experiments, temporal precision in tapping was not related to temporal precision in continuous drawing. There were modest correlations among the tapping tasks, and there were significant correlations among the drawing tasks. In Experiment 3, the function relating timing variance to the square of the observed movement duration for tapping was different from that for drawing. The conclusions drawn were that timing is not an ability to be shared by a variety of tasks but instead that the temporal qualities of skilled movement are the result of the specific processes necessary to produce a trajectory. These results are consistent with the idea that timing is an emergent property of movement.