Similar as well as dissimilar contextual stimuli increase rated similarity

Contextual stimuli from one category increase the rated similarity of stimuli from a second category. In Experiment 1, associates of one of the members of pairs of target words increased the rated similarity of the members slightly more than did much less similar contextual stimuli. In Experiment 2, contextual category names and good exemplars increased the rated similarity of pairs of poor to medium target exemplars and were also rated as more similar to these targets than the targets were to each other. In both cases, the category names resulted in the stronger effect. This ability of contextually similar stimuli to increase rated similarity opposes the distance-density and averaging-judgmental theories of the effect of context on similarity. However, the theory that a positive association exists between the perceived similarity of stimuli and the strength of the category to which they belong explains how both contextually dissimilar and contextually similar stimuli can increase rated similarity.     

Resilient children,psychological wellness,and primary prevention

The concept of heightened resilience or invulnerability in young profoundly stressed children is developed in terms of its implications for a psychology of wellness and for primary prevention in mental health. Relevant literature is reviewed, a skeletal model for studying resilience is outlined, and needed research directions are considered. The latter include expansion of the construct's nomological definitional net, inquiry into the antecedents and determinants of resilience, and the application of such generative information to frame preventive interventions for young, profoundly stressed children.     

The precaution adoption process

This article presents a critique of current models of preventive behavior. It discusses a variety of factors that are usually overlooked-including the appearance of costs and benefits over time, the role of cues to action, the problem of competing life demands, and the ways that actual decision behavior differs from the rational ideal implicit in expectancy-value and utility theories. Such considerations suggest that the adoption of new precautions should be viewed as a dynamic process with many determinants. The framework of a model that is able to accommodate these additional factors is described. This alternative model portrays the precaution adoption process as an orderly sequence of qualitatively different cognitive stages. Data illustrating a few of the suggestions made in the article are presented, and implications for prevention programs are discussed.     

Force variability in isometric responses

In the present study we examined the contribution of different impulse parameters to peak force variability in an isometric task. Five experiments are reported that each held constant a different impulse parameter while allowing the other impulse parameters to vary. The results indicate that change in force level is the parameter that has the greatest effect on peak force variability, although time to peak force and preload also systematically influence response variability. A formula that accommodates the relation between impulse parameters and force variability is proposed. The data suggest that even in isometric tasks, it is the force-time properties of the impulse, rather than discrete parameters such as peak force, that determine the outcome variability.     

A maturation effect in response inhibition in the rat

The finding that there are maturational differences between the ability to learn and to perform a task requiring young Wistar rats to inhibit a response was examined. Using an operant task, different from that employed in the previous studies, it was established that the finding was not task specific. The relative contribution of different periods in the early training stage to later savings in learning was also examined. It was confirmed that there is an early performance deficit by weanling rats on tasks requiring them to inhibit a previously learned response in the presence of a discriminative cue. Rats given early training on the task during this period of performance deficit nevertheless showed significant savings in later learning of the task, indicating that they had learned as much in that stage as they would have if given the same training at an age when performance is at the adult level. It was revealed that despite age-related differences in performance it was not so much the age at which early training took place as the amount of training given that affected later savings. The results are discussed in light of evidence of similar differences between the learning and performance of discrimination tasks exhibited by young children.     

Modulation of male mouse genital sniff, attack, and mount behaviors by urogenital substances from estrous females

The modulation of attacks, genital sniffs, and mounts in male SJL/J mice by ovarian-dependent urogenital substances in the urine voided by estrous females was examined. Urogenital substances were applied onto the external urogenital areas of ovariectomized mice. When compared with urine voided by estrous females, which stimulated genital sniffing, mounting, and reduced aggression, bladder urine was ineffective. Genital sniffing and mounting was stimulated by estradiol-17 beta, vaginal fluids, and preputial extract. Aggression was reduced by estradiol-17 beta, urethral catheterized urine, and vaginal fluids. Preputialectomy reduced, but did not eliminate, urinary stimulation of genital sniffing and mounting. Preputial extract stimulated aggression. Urogenital substances from ovariectomized females were ineffective in reducing attacks and stimulating genital sniffs and mounts. It was concluded that the ovarian-dependent chemosignals in the urine voided by estrous females are contributed by the urethra, vagina, and preputial gland, perhaps in part through the excretion of unconjugated estrogens.     

Does nondirectional signalization of target distance contribute to navigation in the Morris water maze?

The possibility that rats can navigate in the Morris water maze by reducing the difference between the memorized platform scene and the current sensory input was tested in nine blind rats. A computerized videosystem monitored the rats' movements in the pool and converted the rat-target distance into tones the frequency of which increased in 64 equal steps from 120 Hz at 128 cm to 7680 Hz at 0 cm. During 15 days of training to find a fixed platform position from different starting points (12 trials per day) average escape latencies decreased from 39.0 to 25.4 s. The performance significantly deteriorated when the acoustic distance signalization was omitted and/or when the target position was changed form trial to trial. It is concluded that blind rats solved the task by simultaneously employing search strategy based on position responses, mapping using acoustic background beacons, and distance reduction navigation. It is argued that the various strategies are additive and that their relative significance depends of the conditions of the experiment.     

Brain weights correlate with behavioral parameters in individual inbred mice housed in a common and enriched environment

Fifty 8-week-old Balb/c mice were individually identified and housed together in a large and enriched environment for 5 months. Maze and open field exploration, response to an aversive noise, swimming, and induced grooming tests were applied to each mouse in an initial search for possible relationships between brain morphology and spontaneous behavior in isogenic individuals living in a complex social and physical environment. The tasks generated 39 quantitative behavioral indices which include locomotion, rearing, still, and grooming bout frequencies, latencies, total, and mean bout durations. At the end of the tests, the 7-month-old mice were sacrificed and the fresh weights of their whole brain, cerebellum, brain stem, diencephalon, telencephalon, and prosencephalon were rapidly obtained. Behavioral data have wide variations and do not adjust to normal population distributions. Means of the same parameter differ between tests. A Spearman correlation matrix of all data yielded many significant correlations between indices of the same task which can be interpreted in terms of time budget and sequence probability. Significant correlations between indices of different tests suggest diverse emotionalities, exploratory strategies, and motor skills. The correlations between body and brain weights and among separate brain regions were not significant. There were several low but significant correlations between brain weights and behavioral indices. Such correlations, the resulting factors, and significant behavioral differences between mice with large and small brains suggest that mice displaying low motor activity in novel environments have larger brains and forebrain/hindbrain ratios than mice with high activity, and that animals with high scores of some specific behaviors have larger brain areas physiologically related to such behaviors.(ABSTRACT TRUNCATED AT 250 WORDS)