Visual search in multicharacter arrays with and without gaps

Subjects searched through briefly presented arrays of letters in a controlled order, indicating quickly which of two possible targets had occurred. Some arrays contained gaps—three missing letters. Reaction time (RT) and accuracy were both improved by a gap after the target; improvement was less when the gap preceded the target. To account for these results, a new model is proposed, one which calls for overlapping processing of successive array items. This is not a “hybrid” model, but a third alternative between the two extremes of serial (zero overlap) and parallel (complete overlap). Quantified, the overlapping model generates U-shaped serial-position curves and produces RT predictions in good accord with our data from arrays with and without gaps. The predicted functions for RT vs. array size are concave upward; however, for arrays of five or less they are virtually linear and not very different in slope for positive and negative trials. Although this model is primarily designed for RT, with some additional assumptions it can be extended to accuracy results.     

Childhood asthma: family therapy as an adjunct to routine management

A controlled trial of the effectiveness of family therapy for asthmatic children has been completed, and the results indicate that family therapy may have a part to play in the management of asthma. Our observations have shown that an interaction of psychosocial factors can have a significant effect on the course of the asthma by setting up a circular system which may ultimately lead to clinically intractable asthma, as well as intense emotional distress. Treatment is based on an understanding of the interactional model with the aim of interrupting the progressive sequence of events. A family approach is indicated when (1) emotional factors seem to be playing a significant part; (2) the asthmatic child is manifesting behaviour problems; (3) there is evidence of family psychopathology or (4) the asthma is not being reasonably well controlled with conventional methods of management.     

Stimulus control in a simple instrumental task: The role of internal and external stimuli

Two experiments using rats in a straight alley runway task tested the hypothesis that standard stimuli such as tones and lights (“external” stimuli) and schedule-generated aftereffect stimuli (“internal” stimuli) operate similarly and are similarly subject to the compounding rules specified by R. A. Rescorla and A. R. Wagner (In A. Black & W. Prokasy (Eds.), Classical conditioning II: Current theory and research. New York: Appleton-Century-Crofts, 1972). The experimental task was an instrumental analog of the classic blocking experiment (L. J. Kamin, In M. R. Jones (Ed.). In Experiment 1, blocking of an external discriminative stimulus by a different asymptotic discrimination was accomplished. In Experiment 2, blocking of an internal stimulus discrimination by an asymptotic external stimulus discrimination was obtained. The present results support the view that internal and external stimuli are indeed similar and function in the same manner with regard to blocking of stimulus control.     

An informational analysis of actors' and observers' belief attributions in a role-playing situation

An actor's belief in a proposition was inferred by both the actor himself and an observer on the basis of information concerning (a) the actor's preparation and delivery of a speech on the proposition to an unseen audience, and (b) the audience's belief in the proposition. The availability of this information to judges was systematically varied. The position advocated by the actor in his speech and the audience's opinion affected both the actor's belief in the test proposition and the belief attributed to the actor by a disinterested observer. However, neither effect depended upon whether or not other belief-relevant information was also available. These results were interpreted as more consistent with a summative model of information integration than with an averaging model. Actors' behavior had similar effects upon both actors' estimates of how the audience would judge their beliefs and observers' actual estimates of these beliefs. However, these effects were both greater than the effect of their behavior on their own estimates of their beliefs. The apparent strength of the audience's belief in the target proposition had a positive influence upon both actors' beliefs in the proposition and observers' estimates of actors' beliefs, but had a negative, or contrast effect upon actors' expectancies for how the audience would judge their beliefs. Results were more consistent with the differential perspective hypothesis of actor-observer differences proposed by Jones and Nisbett than with the hypothesis that actors and observers differentially weight the implications of their past experience in formulating their judgments. Results had additional implications for the assumptions that persons make when using their behaviors as indications of their beliefs.     

BEHAVIOR ANALYSIS OF MOTION CONTROL FOR PEDIATRIC NEUROIMAGING

Magnetic resonance imaging is a promising technological advance used for research and diagnosis of disease. The procedure has no risks, except when uncooperative patients require sedation. Four normal children participated in simulated scans to study the effects of (a) antecedent changes in the imaging environment and (b) operant conditioning of movement inhibition. Changing the environment can decrease movement, but operant contingencies were necessary to decrease movement to a level that, in most cases, would allow the procedure to occur without sedation.     

Time estimation and expectancies

The purpose of this research was to examine the influence of different types of expectancies on time estimation behavior. In Experiment 1, subjects were led to expect that a given number of trials would occur in a music perception task. In Experiment 2, expectancies concerning the duration of a given waiting period were varied. Results of both experiments indicated that the confirmation/violation of expectancies exerted a significant im acton4urationjudgments. When subjects received more/fewer trials than expected or waited for a duration-that-waslonger/shorter than expected, the total duration of these time spans was over- and underestimated, respectively. Conversely, time estimates were relatively accurate whensubjects' expectancies were confirmed. The results of Experiment 1 further revealedthat reaction time responses within-the-music perception task were also systematically influenced by the expected amount of activity. Results are discussed in terms of a framework that emphasizes the role of anticipatory attending on time estimation behavior.     

Effects of maternal employment patterns on adolescents' substance use and other risk-taking behaviors

Employment for mothers with school-age children has generated great concern regarding its possible harmful effects on adolescents and their families. We examined the influence of maternal employment on the risk-taking behavior of adolescents in two-parent families. Three hundred and eighty-nine high school students completed a 48-item survey in which they indicated their mother's and father's employment patterns, and their own risk-taking behaviors (e.g., substance use, driving while under the influence). Results showed no significant effects of maternal employment on adolescent risk-taking behaviors.     

ALTERING SHOPPERS' SUPERMARKET PURCHASES TO FIT NUTRITIONAL GUIDELINES: AN INTERACTIVE INFORMATION SYSTEM

This study reports the results of one effort to help supermarket shoppers alter food purchases to make purchases (and meals) that are lower in fat and higher in fiber. A prototype interactive information system using instructional video programs, feedback on purchases with specific goals for change, weekly programs, and the ability to track user interactions and intended purchases was evaluated. The major dependent measure was users' actual food purchases as derived from participants' highly detailed supermarket receipts. After a 5- to 7-week baseline phase, participants were randomly assigned to an experimental or control condition for the 7- to 8-week intervention phase. A follow-up phase began 5 to 8 weeks after participants completed the intervention and discontinued use of the system. The results indicated that experimental participants, when compared to control participants, decreased high fat purchases and increased high fiber purchases during intervention, with evidence for some maintenance of effect in follow-up. Plans for increasing the use and impact of the system are discussed.     

An experimental evaluation of a prototype public access nutrition information system for supermarkets

Located the Nutrition for a Lifetime System (NLS-1), a prototype interactive information system, in a large supermarket to help users decrease high-fat food purchases and increase high-fiber food purchases. Study participants were randomly assigned to control (n = 23; used the NLS-1 to enter food purchases only) or experimental (n = 26; viewed videodisc instructional programs, received prompts, made commitments, received feedback from the NLS-1) conditions. According to data entered in the NLS-1 and actual food shopping receipts, experimental participants significantly reduced higher fat purchases. Increases in higher fiber purchases favored the experimental group but were not significant.