Age-dependent facilitation of taste-footshock conditioning by prior exposure to the training context

Among adult rats, gustatory stimuli are easily associated with illness, but not with external unconditioned stimuli such as footshock. Recent evidence indicates, however, that this cue-to-consequence specificity may vary ontongenetically. The present studies examined the acquisition of an aversion to a taste paired with footshock in 5- and 15-day-old rats. Consistent with previous reports, 5-day-old rats avoided the taste that preceded footshock, while 15-day-old subjects did not express an aversion to the taste paired with footshock. Exposure to the training context for either 1 or 5 h prior to conditioning disrupted taste-footshock conditioning in the 5-day-old subjects. For the 15-day-old subjects, 1 h of pre-conditioning exposure to the training context had no effect on conditioning, whereas a longer duration of preexposure promoted conditioning to the taste cue. The results suggest ontogenetic differences in stimulus selection.     

Changes in energy expenditure and work during response acquisition in rats

The principle of least effort predicts that behavior will tend to maximum efficiency. To test this prediction, changes in the energy expended (VO2) and work performed per reinforcement were monitored continuously as rats learned to press a beam with a criterion force for liquid food rewards. All 12 subjects exhibited significant decreases in energy expended per reinforcement over the 16 days of observation. Of these, 10 subjects also decreased the work performed per reinforcement. Analyses of motor performance were undertaken to determine how motor programs for changing efficiency were generated. The 10 animals showing decreased work reinforcement also exhibited significant decreases in the variability of temporal and kinetic response features and in mean response magnitude (time integral of force or work per response) as a function of practice. Adjustments in work output were primarily accomplished by modifying temporal response features (response duration and, initially, interresponse time). The kinetic features (response recruitment and peak force) remained relatively constant for these animals. The remaining 2 subjects differed in that response recruitment increased after Day 9, resulting in progressively larger amounts of work being performed to earn each reinforcement, and the interval between successive reinforcements decreased.     

The Y chromosome, social signals, and offense in mice

Offense is one type of aggression in mice (Mus musculus/Mus domesticus). Offense was measured in a panel of testers design for two congenic strains of mice. The two congenic strains were DBA1Bg and DBA1. C57BL10-YBg. These differ in the Y chromosome. Offense was measured for the following dyadic pairs: Group 1 (DBA1 tested against a DBA1 opponent); Group 2 (DBA1 tested against a DBA1.C57BL10-Y opponent); Group 3 (DBA1.C57BL10-Y tested against a DBA1.C57BL10-Y opponent); and Group 4 (DBA1.C57BL10-Y tested against a DBA1 opponent). Group 1 was more aggressive than Group 3, whereas Group 2 was no more aggressive than Group 4. Thus, when the experimental and opponent pairs have the same Y chromosome, the congenics differ in offense, whereas when the experimental and opponent pairs have different Y chromosomes, the congenics do not differ in offense. These findings are consistent with the hypothesis that these Y chromosomes affect the display of and response to social or other stimuli for offense of mice. These stimuli may be individual recognition chemosignals in urine.     

Odd-item search in pigeons: display size and transfer effects

Pigeons searched arrays of small forms displayed on computer monitors. On each trial, a single target form appeared together with two or more identical distractor forms. A set of six different forms was used in each of three experiments. All possible combinations of these forms, paired as target and distractor, appeared in each experimental session. Both the accuracy and speed of search increased with the number of distractors displayed. When both targets and distractors were new, accuracy was above chance only for the large (24 item) display, where transfer was highly significant. The experiments do not support the attribution to pigeons of a general "oddity concept." Rather, the results suggest that odd-item performance depends in part on a perceptual isolation of the target and in part on familiarity with target-distractor combinations.     

Varieties of size-specific visual selection

Compared time to evaluate stimuli of varying sizes. When Ss expect an upcoming stimulus to be a certain size, response time increases with the disparity between expected and actual size. There are, however, 2 size adjustment processes, and they reflect 2 types of visual selection. In the first, a shape-specific image representation is used to separate a visual object from a superimposed distractor. These representations require the type of slow size scaling demonstrated in imagery experiments. The second size scaling process is faster and not shape-specific. At any given time the visual system is set to process information at a particular scale, and that scale can be adjusted to match an object's size. Because both selection mechanisms depend on size, they probably occur at a relatively low, spatially organized processing level. These findings lead to a new explanation for results that had been taken as evidence for attentional selection at the level of object representations.     

Political and Nonpolitical Authority in Values Education

This article is an examination of the political (public consensus) and nonpolitical authority as a basis for values education in a democratic society. The author advocates that nonpolitical authority can be a basis for defending the teaching of values in public schools.     

Physical fitness, body image, and locus of control in college freshman men and women

This study examined the relations among physical fitness, body image, and locus of control. The Hall-Physical Fitness Test Profile, the Winstead and Cash Body Self-relations Questionnaire (BSRQ) and the Nowicki-Strickland Locus of Control Scale were administered to 243 freshmen. Women were significantly more positive about their physical appearance than men. Men were more positive about their physical fitness than women. Men were more physically fit than women. Men and women scoring in the internal direction viewed the physical fitness domain of their body image positively. Unlike men, internally oriented women had more positive perceptions of the health aspect of their body image. Physically fit men and women had positive attitudes toward the physical fitness component of their body image. Physically fit men differed from physically fit women in that men were more internal and held more positive attitudes toward the physical health dimension of their body images.     

A behavioral quantal theory of brain function: an alternative to Lashley's continuity theory of mass action

A behavioral quantal theory of brain function is formulated on the basis of a newly discovered step-wise relationship invariably present among the findings of three experiments by Tsai, et al. on the effects of (1) cerebral decortication, (2) cranial x-radiation, as well as (3) insulin, metrazol, and electroconvulsive shocks upon white rats' adaptive behavior during their learning of successive habit reversals and one-trial reversal problems. Confirmatory results from earlier investigators who studied effects of various current strengths of ECS upon learning and retention of various maze habits are also cited in support of the behavioral quantal theory of brain function which is proposed here as a close-up, more refined alternative to Lashley's continuity theory of mass action.     

Hypnotic susceptibility and its relationship to outcome in the behavioral treatment of asthma: some preliminary data

12 subjects from an experiment on relaxation therapy for asthma were given the Harvard Group Scale of Hypnotic Susceptibility, Form A. Full scale hypnotic susceptibility scores were positively correlated, at a borderline significance, with improvement in the methacholine challenge test, a measure of asthma severity. Performance on the amnesia item of the Harvard Group Scale was correlated with improvement in self-reported symptoms of asthma.     

Patient variable biases in clinical judgment: conceptual overview and methodological considerations

Specific conceptual factors are presented as having contributed to the negative findings of past psychotherapy bias research. Among these factors are the restrictive nature of both the definition of bias and the model of the biased clinician. A review of published studies of several patient variable biases (e.g., gender, race/ethnicity, and age) indicated that bias may best be defined in broader terms and that its occurrence may be more circumscribed than originally conceived. In addition, the lack of a theoretical perspective in this area of research is noted and the applicability of some social cognitive processes is discussed. Methodological factors are also considered, and recommendations for future research are offered.