Role of eye and hand initial position in the directional coding of reaching

To investigate the nature of the frames of reference used to control an arm movement aimed at a visual target, we studied the accuracy of movements differing by the initial arm and eye positions. The results support the assumption that in darkness target location is internally represented in an egocentric frame of reference. Furthermore, when movements carried out with and without eye saccade are compared, it appears that foveating the target changes the reference used to generate the reaching arm movements, that is, the oculocentric reference is replaced by a head-trunk reference. An explanation for this phenomenon could be that a steady body-related landmark is needed to insure stable registering of the target location in the surrounding space, despite displacement of the body segments with respect to one another.     

FIXED-INTERVAL PERFORMANCE AND SELF-CONTROL IN INFANTS

Twenty-six infants, 3 to 23 months old, were trained on fixed-interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch-sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six-phase self-control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5-s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self-controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed-interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self-controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed-interval schedule (classified as pause-sensitive subjects) or produced short pauses and higher steady response rates (classified as pause-insensitive subjects). All pause-sensitive subjects made self-controlled choices in the self-control condition, and all pause-insensitive subjects made impulsive ones.     

The gender role journey measure: Scale development and psychometric evaluation

The Gender Role Journey concept was developed to help women and men explore their gender role changes and transitions. A 34-item Gender Role Journey Measure (GRJM) was conceptualized and developed through empirical methods. The construct validity of the five phases of the gender role journey is assessed. The GRJM and the Personal Attributes Questionnaire (PAQ) were given to a sample of women and men (N=878). The sample was predominantly Caucasian from a mixed ethnic background. Principle factor analysis indicated three meaningful factors: Acceptance of Traditional Gender Roles; Gender Role Ambivalence, Confusion, Anger, and Fear; and Personal-Professional Activism. Moderately high test-retest and internal consistency reliabilities were found for each of the factors. Gender differences and gender by PAQ interactions were found for all three of the factors of the GRJM. Implications for future research, teaching, and workshops are suggested.This article was presented at the 99th convention of the American Psychological Association, San Francisco, California, August 1991. It was supported by a grant from the Research Foundation of the University of Connecticut, Storrs, Connecticut.     

Differences in extracurricular activity participation, achievement, and attitudes toward school between ninth-grade students attending junior high school and those attending senior high school

The purpose of this study was to determine the type of school organization that most benefited ninth-grade students. Results indicated that ninth graders in the junior high school setting participated significantly more in extracurricular activities and achieved significantly higher academically than did ninth graders in the senior high school setting.     

Search behaviour of cats (Felis catus) in an invisible displacement test: cognition and experience

An invisible displacement test was administered to cats in order to test the hypothesis that search behaviour in this species is influenced by their limited capacity for object permanence as well as by their previous experience with the environment. Experiment 1 compared three groups of cats in a five-choice hiding task in which the hiding places could be discriminated by their spatial positions. Two groups received a visible displacement training before the invisible displacement test and one group did not. Experiment 2 compared two groups of trained subjects in the same task, but the hiding places could be discriminated by spatial and visual cues. The results confirmed that cats are unable to solve problems with invisible displacements. The visible displacement training improved their performance, but was not sufficient to make them succeed. Experience with the hiding potential of the covers also gives more persistence to search behaviour. Finally, the distribution of search attempts is not determined by the proximity to the target and is influenced only partially by the subjects' previous experience. Like Stage 5 infants, cats rely mainly on their immediate perception. They search for an object in the last location they have seen it disappear or under the nearest cover from this location.     

Peer-group association and adolescent tobacco use

Mosbach & Leventhal (1988) examined the relation of cigarette smoking to peer-group identification in rural Wisconsin adolescents. They found that among dirts (problem-prone youth), regulars (average youth), hot-shots (good social or academic performers), and jocks (athletes), youth most likely to smoke were dirts and hot-shots. We performed a replication with a Southern California cohort and also for use of smokeless tobacco. We hypothesized that jocks would be the main users of smokeless tobacco. We identified the same groups and an additional one, skaters (skateboarders or surfers). As Mosbach & Leventhal found, cigarettes were used most by dirts. Contrary to their results, but consistent with other research, we found that hot-shots were least likely to smoke. Contrary to our prediction, we found that skaters and dirts were more likely to use smokeless tobacco than were jocks. Our data show that both tobacco forms are used by problem-prone youth.     

Second-Guessing the Jury: Stereotypic and Hindsight Biases in Perceptions of Court Cases1

This research examined the effects of stereotypic beliefs and hindsight biases on perceptions of court cases. Subjects read evidentiary material pertaining to a criminal trial in which the defendant either was a stereotyped offender or was not. Additionally, some subjects were given outcome information about the verdict attained in the trial; half of these subjects were told that the defendant had been found guilty, and the other half were told that he had been found not guilty. The remainder were not given any outcome information. Subjects were than asked to predict the likely outcome of a trial based on the presented evidence. Typical hindsight bias effects were expected and obtained for nonstereotyped offenders; subjects considering these cases viewed the evidence as less incriminating when they were told the defendant had been found not guilty, and they found it to be more incriminating when they were told the defendant had been found guilty, when compared to the no-outcome-information group. However, no hindsight biases were evident in judgments of cases involving stereotyped defendants, who were seen as relatively more likely to be guilty regardless of the nature of outcome information presented. Particularly striking was the lack of impact of the “not guilty” outcome information on perceptions of the guilt of stereotyped defendants. These findings suggest that strong expectations held in foresight may not be amenable to modification in hindsight.     

Temporal learning in 4 1/2- and 6-year-old children: role of instructions and prior knowledge

The present study investigates effects of different types of instructions (high-rate, interval, and minimal) during training with a fixed-interval schedule as a function of prior acquired temporal knowledge. A pretest was used to assess 4 1/2- and 6-year-old children's ability to understand the temporal parameters of a fixed-interval schedule of reinforcement. The results as a whole show that the control exerted by instructions given by the experimenter or elaborated by the subjects themselves on fixed-interval performance of young children depends on the interaction of two factors: development of verbal self-control skills and mastery of knowledge required by the rules forming the instructions.