Overshadowing in operant conditioning as a function of discriminability

Pigeons were trained in an operant, go/no-go, discrimination by successive presentations of discrete, positive and negative trials. In separate groups, the rate of discriminaion learning based on an auditory cue, on visual cues of different discriminability, and on combined auditory and visual cues was determined. The auditory cue was tone/no-tone, the visual cue was a difference in brightness level on the key. Following discrimination training, stimulus control was tested in extinction by presenting tone or notone at each of four key-brightness levels.Learning was more rapid with two cues than with either cue singly, demonstrating summation. The contribution made by the tone cue to the learning of the discrimination decreased with increasing discriminability of the light cue. The control exerted by the tone cue also decreased (i.e., the tone cue was overshadowed) with increasing discriminability of the light cue. In certain cases, the tone cue decreased control by brightness, showing that in two-cue discriminations each cue may reduce the control exerted by the other.     

Sex differences in interaction style as a product of perceived sex differences in competence

Males' and females' interaction styles were observed while they worked in four-person, mixed-sex groups on a discussion task. In some groups, members were only given information about each others' names and gender. In this circumstance, men were perceived by themselves and other group members to be higher in competence than women. Further, men engaged in a greater amount of active task behavior than women (e.g., giving information, giving opinions), and women exhibited a greater amount of positive social behavior than men (e.g., agreeing, acting friendly). In other groups, members' competency-based status was manipulated by providing false feedback that they were high or low relative to their group in intellectual and moral aptitude. High status members were then perceived to be more competent than low status ones and, further, high status individuals engaged in more active task and less positive social behavior than low status ones. In this condition, no sex differences were obtained on perceived competence or on active task or positive social behavior. Overall, these findings support the idea that the gender differences obtained in interaction when status was not specified were partially a function of group members' belief that the sexes differ in competence. Direct information concerning members' intellectual and moral competence apparently blocked the perceived gender-to-competence link, and status alone affected perceived competence and interaction style.     

The development of language as a function of programmed conditioning

This paper is an extension of an earlier article by the authors concerning procedures for conditioning language behavior in linquistically divergent children. Specifically, this paper deals with the role and importance of response generalization in the development of syntax. The results suggest that the conditioning method used was effective in obtaining the necessary generalization.