Effects of preshift small magnitude of reward received during goalbox placements on the negative contrast effect

During preshift, one experimental group of rats was given a large magnitude of food reward following a traversal of a straight alley and during a goalbox placement, while the other experimental group was given a small reward during goalbox placement and a large reward following a run. During postshift, all experimental groups were given a small reward of food following a traversal down the runway and during a goalbox placement. A control group was maintained on small reward during placements and following a traversal throughout the study. Only the group who received preshift large reward during placement and following a runway response ran slower to small reward during postshift than the control group maintained on small reward (negative contrast effect).     

Selective Synaptic Plasticity within the Cerebellar Cortex Following Complex Motor Skill Learning

Complex motor skill learning, but not mere motor activity, leads to an increase in synapse number within the cerebellar cortex. The present experiment used quantitative electron microscopy to determine which synapse types were altered in number. Adult female rats were allocated to either an acrobatic condition (AC), a voluntary exercise condition (VX), or an inactive condition (IC). AC animals were trained to traverse an elevated obstacle course requiring substantial motor coordination to complete. VX animals were housed with unlimited access to running wheels and IC animals received no motor training but were handled briefly each day. Results showed the AC animals to have significantly more parallel fiber to Purkinje cell synapses than both the VX and IC animals. No other synapse type was significantly altered. Thus, the learning-dependent increase in synapse number observed within the cerebellar cortex is accomplished primarily through the addition of parallel fiber synapses.     

Self-Esteem, Erotophobia, and Retention of Contraceptive and AIDS Information in the Classroom

It has been well documented that people with negative emotional reactions to sex (e.g., "erotophobia,""sex guilt") have less knowledge about contraception than do people with more positive reactions. Recent research has suggested that this deficit is not related to an inability to learn the information, but is due at least in part to the fact that erotophobics actively avoid contraceptive information. The current study was designed to examine the role of erotophobia and high self-esteem in resistance to learning sexual information. More specifically it compared pretest and posttest knowledge of contraception and AIDS in high self-esteem and low self-esteem, erotophobia, and erotophilic women in a university class on human reproduction. As expected, high self-esteem erotophobic subjects were less Likely than other subjects to retain contraceptive and AIDS information presented in the class. Implications of this study for contraceptive and AIDS educational strategies are discussed.     

The Acquaintance Predicament of a Rape Victim1

The acquaintance predicament of a rape victim was examined in six experiments with between-subjects designs with samples drawn from the undergraduate student population of the University of Bombay. The experiments used rape vignettes for the manipulation of all independent variables except subject's sex and were done in three pairs such that each pair had the same independent variables and first dependent measure, namely, recommended years of imprisonment for the rapist. The second dependent measure was attributed victim's fault in the first experiment and perceived likelihood of rape in the second experiment of each pair. The first pair of experiments had a 2 (subject's sex) × 2 (acquainted vs. unacquainted rapist) × 3 (rapist's status: manager, stenotypist, or watchman) × 2 (complaint vs. no complaint by victim) design, with the rape victim being described as a stenotypist. The second pair of experiments differed from the first pair in only one respect, with victim's marital status (married vs. divorced victim) replacing the independent variable of complaint of the first pair. The third pair of experiments had a 2 (subject's sex) × 2 (physically hurt vs. not hurt victim) × 5 (rapist's relationship with victim: husband, fiance, friend, acquaintance, or stranger) design. Female subjects, as compared to male subjects, recommended longer imprisonment for the rapist, attributed less fault to the victim, and perceived greater likelihood of rape. The victim was attributed less fault in case of stranger rape versus acquaintance rape and also less fault in the complaint versus the no complaint condition. Longer imprisonment was recommended for the rapist when the victim was physically hurt rather than not hurt.     

Bullying in elementary school, high school, and college

This study investigated the continuity in being a bully, victim, or bully-victim from elementary school through college in 119 undergraduates. Of 25 who bullied in college, 18 (72%) had been bullied in high school and elementary school. Of 26 bullies in college, 14 (53.8%) had been bullies in high school and elementary school. Of 12 bully-victims in college, 5 (41.6%) had been bully-victims in high school and elementary school. There were significant positive correlations between being a bully in college, high school, and elementary school, and being bullied in college and high school, and high school and elementary school, and between being both a bully and victim in elementary school, a bully and victim in high school, and a bully and victim in college.     

Withdrawal from cocaine self-administration produces long-lasting deficits in orbitofrontal-dependent reversal learning in rats

Drug addicts make poor decisions. These decision-making deficits have been modeled in addicts and laboratory animals using reversal-learning tasks. However, persistent reversal-learning impairments have been shown in rats and monkeys only after noncontingent cocaine injections. Current thinking holds that to represent the human condition effectively, animal models of addiction must utilize self-administration procedures in which drug is earned contingently; thus, it remains unclear whether reversal-learning deficits caused by noncontingent cocaine exposure are relevant to addiction. To test whether reversal learning deficits are caused by contingent cocaine exposure, we trained rats to self-administer cocaine, assessed cue-induced cocaine seeking in extinction tests after 1 and 30 d of withdrawal, and then tested for reversal learning more than a month later. We found robust time-dependent increases in cue-induced cocaine seeking in the two extinction tests (incubation of craving) and severe reversal-learning impairments.     

Perceptual complexity,rather than valence or arousal accounts for distracter-induced overproductions of temporal durations

For humans and other species, the ability to estimate the physical passage of time is of fundamental importance for perceptual, cognitive or motor functions. Despite this importance, any subjective estimation of temporal durations not only depends on the temporal dynamics of the to-be-timed stimulus or event, but also can be distorted by non-temporal perceptual, cognitive, and emotional effects. This study aimed to further explore critical stimulus characteristics modulating distracter-induced distortions in human time-reproduction. To this end, we investigated whether subjectively rated distracter dimensions of arousal and valence (related to levels of emotionality), or rather stimulus complexity, as a confounder, produce distortions in participants' reproduction of a previously trained target interval. Accuracy and precision of time-reproduction have been measured in distracter-trials, and compared to timing performance in baseline-trials without any distraction. Results showed temporal overproductions in a magnitude of less than distracter duration only for complex distracters. Most importantly, arousal level and valence of distracters were not accountable for temporal distortions. Within an internal clock framework, our pattern of results can best be interpreted in the context of attention-, rather than arousal-based mechanisms of timing.     

Adolescents let sufficient evidence accumulate before making a decision when large incentives are at stake

Adolescent decision‐making has been described as impulsive and suboptimal in the presence of incentives. In this study we examined the neural substrates of adolescent decision‐making using a perceptual discrimination task for which small and large rewards were associated with correctly detecting the direction of motion of a cloud of moving dots. Adults showed a reward bias of faster reaction times on trials for which the direction of motion was associated with a large reward. Adolescents, in contrast, were slower to make decisions on trials associated with large rewards. This behavioral pattern in adolescents was paralleled by greater recruitment of fronto‐parietal regions important in representing the accumulation of evidence sufficient for selecting one choice over its alternative and the certainty of that choice. The findings suggest that when large incentives are dependent on performance, adolescents may require more evidence to accumulate prior to responding, to be certain to maximize their gains. Adults, in contrast, appear to be quicker in evaluating the evidence for a decision when primed by rewards. Overall these findings suggest that rather than reacting hastily, adolescents can be incentivized to take more time to make decisions when large rewards are at stake. A video abstract of this article can be viewed at http://youtu.be/1g4F5vzFDl0