Density effects in conjunction search: evidence for a coarse location mechanism of feature integration.

Four experiments used the visual search paradigm to examine feature integration mechanisms. Reaction time to determine the presence or absence of a conjunctive target is relatively fast and exhaustive for low-density displays. Search rate is slow and self-terminating for high-density displays. Density effects do not arise when the target is defined by a unique feature. Two mechanisms are proposed for feature integration. A fast mechanism integrates features on the basis of coarse location information coded with the initial registration of the features. This coarse location mechanism requires that display items be spaced apart. A second, slower mechanism is used when objects are clumped together. The 2-mechanism hypothesis provides a resolution to conflicting findings in the visual search and illusory-conjunction literature. A possible interpretation of the findings with a single guided search mechanism for feature integration is also discussed.     

Septal lesions lower responding under fixed-ratio schedules of reinforcement.

Albino Sprague-Dawley rats with complete septal lesions and rats with control operations were studied under fixed-ratio (FR) schedules of reinforcement. Both groups were trained for 10 sessions each under FR 10, 20, 40, 60, 80, and 100. In contrast to findings from progressive FR studies and some simple FR studies, septal lesions resulted in lower overall and local response rates along with longer postreinforcement pauses. These effects were especially evident during the FR 100 schedule of reinforcement. A comparison of reinforcement rate as a function of FR size within the context of behavioral economics (i.e., a demand function) indicated that septal lesions did not alter the reward value of food. These findings suggest that responding on FR schedules of reinforcement can be altered by the various procedures used to train rats to reach the terminal value of a reinforcement schedule.     

The shifting salience of valence and instrumentality in the prediction of perceived effort,satisfaction and turnover

The role of valence and instrumentality was examined in predicting three work-related criteria in a military setting: satisfaction, perceived effort, and turnover. A total of 323 enlisted men responded to desirability and instrumentality scales for each of four categories of performance outcomes: extrinsic rewards, personal fulfillment, recognition, and autonomy. Multiple regression analyses indicated that the different outcome types varied substantially in their relationship to the criteria, ranging from strongly positive to no relationship to strongly negative. Furthermore, the salience of valences and instrumentalities changed as a function of the criterion being predicted in a manner not deducible from current expectancy-valence models. Several implications of the results were discussed in terms of assumptions underlying general expectancy-valence approaches to motivation.This research was supported in part by Grant DAHC19-77-G0017 to New York University (Samuel Shiflett, principal investigator) from the Army Research Institute for the Behavioral and Social Sciences. This work was conducted while the authors were members of the Army Research Institute. The interpretations and opinions expressed herein are those of the authors and do not necessarily reflect the opinions or policies of the Department of the Army or the Department of Defense. The authors gratefully acknowledge the support and assistance of John Turney at various stages of the project.     

Life change and the sensation seeking motive

College undergraduates were administered the Life Experiences Survey, the Discomfort scale of the Psychological Screening Inventory, and the most recent version of the Sensation Seeking Scale. The findings did not replicate Smith et al.'s results concerning the role that sensation seeking plays in the relationship between negative life change and psychological distress. However, the data suggest that the sensation seeking motive is a causal variable that is predictive of recent life events that college students have experienced, and that future life-stress research should examine the occurence of controllable life events as a function of subjects' personality traits.     

Cognitions, affect, and behavior following uncontrollable outcomes: A response to current human helplessness research

A series of articles in the Journal of Personality challenge several central assumptions of the reformulated learned helplessness model: that perceptions of uncontrollability, awareness of noncontingency between responses and outcomes, and attributions made about the outcome are necessary to explain learned helplessness effects. The present article addresses the validity of this challenge through a consideration of the methodology employed in these and other traditional studies of human helplessness conducted in the laboratory. We maintain that although performance deficits can be demonstrated reliably following exposure to uncontrollable outcomes, a number of factors other than expectations of future uncontrollability (i.e., learned helplessness) may be responsible for these effects. In addition, demands of the experimental situation may prevent subjects from admitting their true underlying thoughts and feelings regarding the manipulations employed. Finally, the current use of artificial laboratory paradigms may unnecessarily restrict the study of a complex psychological phenomenon such as learned helplessness. We suggest that future researchers employ paradigms that more closely parallel real world situations to which they hope to generalize, or utilize naturally occurring uncontrollable life events to study the problem. In addition, we argue that future research should broaden its focus beyond attributions to explore other mediators of human helplessness.     

Effects of an observer on eating behavior: the induction of "sensible" eating.

An experiment was conducted to investigate the extent of caloric compensation to differential preloading among normally restrained and unrestrained female subjects. Subjects' eating was either explicitly observed or unobserved by the experimenter. Unrestrained eaters compensated appropriately for the preload, whether or not they were observed. Restrained eaters failed to compensate when unobserved , but compensated strongly when observed. A subsequent unobserved eating task revealed that restrained eaters failed to compensate for prior consumption when the observer was withdrawn. Implications for research and therapy are discussed.     

Ambiversion: characteristics of midrange responders on the Introversion-Extraversion continuum

Sixty-nine midrange responders on the Introversion-Extroversion (IE) scale of the Eysenck Personality Questionnaire (EPQ) were given an experimental measure to assess tendency toward ambivalence (i.e., both strongly introverted and strongly extraverted responses) vs. moderation (i.e., midrange responses), and degree of importance given to IE types of activities. The participants were divided into those showing ambivalence vs. those showing moderate responses, and into those reporting high vs. low importance of such activities. As was predicted, the ambivalent group showed significantly higher scores on the neuroticism scale of the EPQ, while the low importance group tended to show more psychoticism, but not to a significant degree. Both of the midrange scores were unrelated to the Bem Sex Role Inventory. Based on the findings, at least two groups are posited in the midrange of the IE dimension: an ambivalent group with mixed strong introversive and extraversive tendencies, and an ambiverted group with midrange scores.     

Some problems of Wilson's disease

The Leipzig Center for Wilson's Disease in the GDR is charged with the registration and diagnosis of all homozygous Wilson gene carriers, the clarification of all suspected cases, including the heterozygote test, and the co-ordination of long-term treatment. At present, there are 78 recorded Wilson gene carriers living. On the basis of our own comprehensive observations and investigations over prolonged periods of time, questions concerning pathogenesis, genetics, diagnosis and therapeutic measures, including their side-effects, are dealt with.     

Communication patterns in pedodontics.

This investigation examined communication patterns between 16 randomly selected senior dental students and their child patients. Interactions were videotaped during a regular treatment appointment and analyzed according to four Practitioner Communication categories and four Child Cooperation categories. Communication categories included Directive Guidance Behavior, Permissive Behavior, Coercive Behavior, and Other Behavior. Child behavior categories included Cooperation, Resistance, Noncooperation, and Other. The probability that a given category of child's behavior would follow a given category of practitioner's behavior was calculated. Results indicated a .85 probability that Directive Guidance would be followed by Cooperation; a .67 probability that Permissiveness would lead to Noncooperation; and a .97 likelihood that Coerciveness would lead to either Noncooperation or Resistance. Practitioners' confidence was also considered; less confident operators account for 95% of the Coercive behaviors, 86% of Permissive behaviors and 87% of Uncooperative behaviors.