Temporal proximity and reinforcement sensitivity in multiple schedules

Distributions of reinforcers between two components of multiple variable-interval schedules were varied over a number of conditions. Sensitivity to reinforcement, measured by the exponent of the power function relating ratios of responses in the two components to ratios of reinforcers obtained in the components, did not differ between conditions with 15-s or 60-s component durations. The failure to demonstrate the “short-component effect,” where sensitivity is high for short components, was consistent with reanalysis of previous data. With 60-s components, sensitivity to reinforcement decreased systematically with time since component alternation, and was higher in the first 15-s subinterval of the 60-s component than for the component whose total duration was 15 s. Varying component duration and sampling behavior at different times since component transition may not be equivalent ways of examining the effects of average temporal distance between components.     

Development of learning-disabled and normally achieving children's causal attributions

The causal attributions of learning-disabled (LD) and normally achieving (NA) children in grades 3 through 8 were compared. Attributions were measured by two scales that asked children to attribute hypothetical academic failure situations to factors that were either within (e.g., insufficient effort) or beyond (e.g., insufficient ability, blaming others) their control. Consistent with a learned helplessness hypothesis, LD girls, regardless of age, were more likely than NA children to attribute their failures to factors beyond their control. In contrast, LD boys' explanations for their failures paralleled those of NA children. That is, with increasing age the LD boys were more likely to attribute their failures to insufficient effort. Explanations and implications of sex differences in developmental patterns of LD children's causal attributions are discussed.The authors wish to thank Ruth Dusseault and Betty Wallace for their help in conducting this research. We also wish to thank the teachers, children, and administrators from the Leon County Schools for their cooperation.     

Duration of negative practice and the reduction of leg pounding of a traumatically brain-injured adult

This study evaluated the relative efficacy of long (1 minute) and short (15 seconds) durations of negative practice for reducing self-stimulatory leg pounding of a traumatically brain-injured adult. In individual social skill training classes, long negative practice and short negative practice were administered concurrently in an alternating treatments design. Generalization of treatment effects outside of training sessions was assessed during the client's lunch period. The results revealed that both durations of negative practice were equally effective in reducing leg pounding during training sessions. However, the effects of training did not generalize to settings in which the practice contingency was not enforced. Pounding was more frequent and negative practice somewhat less effective during periods of high social stimulation.     

Exploratory study of best friendship dissolution characteristics and psychological difficulties during early adolescence

Few studies have evaluated best friendship dissolutions and especially the circumstances surrounding the dissolutions. In this exploratory study of young adolescents (N = 273, M_age = 11.83 years; 51% boys), we investigate young adolescents' experiences with two types of best friendship dissolution (complete dissolutions, downgrade dissolutions) and two characteristics of such experiences: initiation status (self- versus friend-initiation) and emotional reactions (degree of happiness, anger, sadness, and embarrassment). We also consider whether these characteristics of best friendship dissolutions are related to psychological difficulties (loneliness, depressive symptoms). Results indicated that most young adolescents perceive their friends initiated their recent complete and downgrade dissolutions. When young adolescents did initiate their complete dissolutions, however, they reported less negative (anger) and more positive (happiness) emotional responses. Initiation status was not related to psychological difficulties, but variability in several types of emotional responses (e.g., embarrassment) was related to variability in loneliness and depressive symptoms. Findings underscore the importance of considering not only the type of dissolution, but also the circumstances surrounding dissolutions, during early adolescence.     

Ambiguity attitudes in qualitative contexts: The role of prior beliefs

Most studies of ambiguity aversion rely on experimental paradigms involving monetary bets. Thus, the extent to which ambiguity aversion occurs outside of such contexts is much less understood, particularly when the situation cannot easily be reduced to numerical terms. The present work seeks to understand whether people prefer to avoid ambiguous decisions in a variety of different qualitative domains (e.g., work, family, love, friendship, exercise, study, and health), and, if so, to determine the role played by prior beliefs in those domains. Across three studies, we presented participants with 24 vignettes and measured the degree to which they preferred risk to ambiguity in each. We also asked them for their prior probability estimates about the likely outcomes in the ambiguous events. Ambiguity aversion was observed in the vast majority of vignettes, but at different magnitudes. It was predicted by whether the vignette involved gain or loss as well as by people's prior beliefs; however, the heterogeneity between people meant that the role of prior beliefs was only evident in an individual-level analysis (i.e., not at the group level). Our results suggest that the desire to avoid ambiguity occurs in a wide variety of qualitative contexts but to different degrees for different people and may be partially driven by unfavorable prior estimates of the likely outcomes of the ambiguous events.