Central-place foraging by Rattus norvegicus on a radial maze

We studied central-place foraging in rats (Rattus norvegicus) by placing food items that varied in size and weight at the ends of a 4-arm radial maze. In Experiments 1-3, rats increasingly tended to carry food to the center of the maze as the size of those items increased. Very large food items often were hoarded in the center. Rats consumed food faster on the arms than in the center, and rats traveled faster when carrying food than when not. Blocking arm entrances increased travel time between the center and the arms and decreased food carrying at every item weight except the largest. In Experiments 4-6, important conditions that influence the degree of food-carrying behavior were discovered; these were the intersection of maze arms, the presence of a conspecific, and the use of open vs. closed maze arms.     

Timing multimodal events in pigeons

The peak procedure was used in two experiments to study pigeons' ability to time multimodal events. In the first experiment, birds were trained to time a single event consisting of a 9-s tone or light followed by a 21-s fixed interval associated with a signal of light or tone (signal of the other modality). On occasional empty trials, different lengths of the first signal were followed by a long period of the second signal. Peak response times as a function of the duration of the first signal were linear and had a slope of close to one in all birds. This indicates that the birds were timing only the second signal. In a second experiment, two complex events were used in training. One consisted of a 9-s tone or light followed by a 21-s fixed interval associated with a light or tone. The other consisted of a 21-s tone or light followed by a 9-s fixed interval associated with a light or tone. Different durations of the first signal were again used on empty trials. Peak response times as a function of the duration of the first signal were again linear in all birds. The slope of the function was less than one but greater than zero for 3 birds. This indicates that these birds were partly timing the entire complex event of 30-s duration and partly timing only the second signal of the event. A model is proposed in which the bird takes as a criterion for timing a weighted average of different target criteria. Comparisons with the performance of rats are made.     

The wilderness therapy program: An empirical study of its effects with adolescents in an outpatient setting

The results of a study of the Wilderness Therapy Program involving 23 adolescents in outpatient counseling are presented. Data were collected before and after four trips on measures of locus of control, behavioral symptoms, self-efficacy, self-esteem, and a number of measures designed specifically for this program. Following a one and one-half to two week backpacking trip that included daily therapy, significant change was found for locus of control, self-esteem and symptom reduction. Positive changes were noted on the other measures as well. Future directions and social work implications were discussed.     

Effects of test anxiety, tests, and sleep on children''s performance

This study examined the interrelationship between children's test anxiety, sleep, and performance. The subjects, 239 sixth and seventh graders, responded to questionnaires examining sleep behavior and test anxiety on a day when they had a major exam in school, and on a day when they did not. They also completed a vigilance task on both days. The results showed that partial sleep loss (i.e., under 3 hr) did not adversely influence subjects' performance on the vigilance task or on the actual class exam. However, the results did reveal that test anxiety was negatively related to performance on the class exam.     

Intervening causation and the mitigation of responsibility for harm doing II. The role of limited mental capacities

The present study investigated (i) the conditions under which the proximal cause of an event affects judgments of a distal cause, (ii) the capacities persons need to be held responsible for their actions, and (iii) the relationship between judgments of causation, blame, and restitution. Subjects read about situations in which an initial act, in combination with a later behavior by a second person, produced harm. The age and mental state of the second person were varied. It was found that cause and blame assigned to the initial action was greater when the second person was a child or mentally disturbed, as compared to a sane adult. Causal and moral responsibility were related to the understanding, reasoning capacity, and ability to control behavior of the person judged. Finally, support was obtained for an entailment model of the relations between judgments of causation, blame, and restitution.     

The inequivalence of self-reports of Type A behavior: Differential relationships of the Jenkins Activity Survey and the Framingham cale with affect,stress, and control

The Jenkins Activity Survey (JAS) and the Framingham Type A Scale (FTAS) have been found to have different psychological correlates. The JAS is typically unrelated to anxiety, while the FTAS is consistently correlated with trait anxiety. The present study of 200 male and female college students clarifies further the psychological heterogeneity of these measures. Enhanced motivation to control the environment has been suggested as an underlying psychological component of Type A behavior (Glass, 1977). Dysphoric emotions and the perception of more environmental stresses, on the other hand, are typical of neuroticism or negative affectivity (Watson & Clark, 1984). Although the results indicate that the JAS and FTAS are highly correlated, the JAS is more closely related to control motivation than is the FTAS. Further, compared to the JAS, the FTAS is more closely correlated with dysphoric emotions and perceived daily stresses. Thus, the results indicate that the JAS is closely correlated with core psychological components of the Type A pattern, while the FTAS has a relatively unique association with general emotional distress. Such differences may account for the fact that these measures are related to different disease end points.     

Effect of classical conditioning on an internal clock

Six experiments with rats used a psychophysical choice procedure to study the internal clock used to discriminate duration. They investigated if the clock is sensitive to the signal value (associative strength) of a stimulus. The experiments involved two types of trials. On choice trials, a stimulus lasted a short (e.g., 3 s) or long (e.g., 12 s) duration; then the rats chose between two levers. The rewarded choice depended on the duration of the stimulus. On conditioning trials, the stimulus used on choice trials was presented, but it ended without food (extinction trials) or with food (pairing trials) regardless of what the rat did. The main stimulus minus accuracy with the long stimulus. Experiment 1 showed that extinction trials increased short bias relative to training without conditioning trials or to training with pairing trials. The rest of the experiments tested explanations of these results. The same results were found when extinction trials were the same duration as the short stimulus (Experiment 2), when extinction trials were a random duration (Experiment 5), and when the signal value of the conditioned stimulus was changed in another way (Experiment 6). The effect of conditioning trials was modality specific (Experiments 3 and 4). Of the explanations considered, the best one--the only one not contradicted at least once--is that changing the signal value of a stimulus changes how the clock times the stimulus. Reducing signal value reduces the measured duration.     

Development and evaluation of an inventory to assess adult stutterers'' communication attitudes

The purpose of this study was to develop and evaluate a procedure to assess adult stutterers' communication attitudes. To this end, the investigation was divided into two phases. In Phase I, an assessment inventory based on a tripartite attitudinal model was developed and administered to 107 adult stutterers. Reliability and validity of these procedures were examined, and the inventory was refined. In Phase II, reliability and validity of the attitude assessment procedures were reassessed, and the attitudes of 26 stutterers and 56 nonstutterers were examined. Assessment procedures involved a self-report inventory, which obtained ratings of items in 13 situational subscales representing different speaking situations. These situations were rated using four response scales reflecting behavioral, affective, and cognitive aspects of attitude. Situational responding, response scale scores, and response scale interrelationships are examined. Findings are discussed in terms of the potential value of the inventory and future investigations.     

Levinsonian studies of women's adult development

We reviewed four unpublished dissertations that used Levinson's theory to study women's adult development. The 39 biographies presented in these studies suggested that the women progressed through the same developmental periods as had men in Levinson's study and at roughly the same ages. Although the timing of the periods and the nature of the developmental tasks appeared to be similar, the ways of working on these tasks as well as the outcomes achieved were different. These differences are understood in part as consequences of the greater complexity of women's dreams and the problems encountered in living them out.     

A taxonomy of item response models

A number of models for categorical item response data have been proposed in recent years. The models appear to be quite different. However, they may usefully be organized as members of only three distinct classes, within which the models are distinguished only by assumptions and constraints on their parameters. “Difference models” are appropriate for ordered responses, “divide-by-total” models may be used for either ordered or nominal responses, and “left-side added” models are used for multiple-choice responses with guessing. The details of the taxonomy and the models are described in this paper. The present study was supported in part by two postdoctoral fellowships awarded to Lynne Steinberg: an Educational Testing Service Postdoctoral Fellowship at ETS, Princeton, NJ and an NIMH Individual National Research Service Award at Stanford University, Stanford, CA. Helpful comments by the editor and three anonymous reviewers are gratefully acknowledged.