Instrumental responding following reinforcer devaluation

In two experiments, hungry rats were given instrumental lever-press training for an appetitive reinforcer and, in addition, were exposed to another type of food which was not contingent on lever pressing. In the first experiment, exposure to each type of food was on separate days, whereas in the second experiment rats were exposed to each type of food in strict alternation within each session. Subsequently, a food aversion was conditioned to the reinforcer for the experimental group and to the non-contingent food for the control group. In both experiments, animals with an aversion to the reinforcer responded less in an extinction test than animals with an aversion to the non-contingent food. Subsequent reacquisition tests confirmed that the aversion to the non-contingent food in the control group was of comparable strength with that to the reinforcer in the experimental group. The results were discussed in terms of whether the reinforcer is encoded in the associative structure set up by exposure to an instrumental contingency.     

Influence of Connectives on Language Comprehension: Eye tracking Evidence for Incremental Interpretation

An eye-tracking experiment investigated whether incremental interpretation applies to interclausal relationships. According to Millis and Just's (1994) delayed-integration hypothesis, interclausal relationships are not computed until the end of the second clause, because the processor needs to have two full propositions before integration can occur. We investigated the processing of causal and diagnostic sentences (Sweetser, 1990; Tversky & Kahneman, 1982) that contained the connective because . Previous research (Traxler, Sanford, Aked, & Moxey, 1997) has demonstrated that readers have greater difficulty processing diagnostic sentences than causal sentences. Our results indicated that difficulty processing diagnostic sentences occurred well before the end of the second clause. Thus comprehenders appear to compute interclausal relationships incrementally.     

Studies of psychosocial influences on coronary artery atherogenesis in cynomolgus monkeys

The cynomolgus macaque provides a suitable primate model for studying how psychosocial factors contribute to coronary artery atherogenesis. Important interactions with diet, sex, and behaviorally elicited cardiovascular reactivity are described.     

Family interaction and child psychopathology: A comparison of two observation strategies

We examined two systems of assessing family interactions that are in common usage: a home based observation of free parent-child interaction and a clinic based observation of a structured mother-child problem solving discussion. Participants were 18 depressed, 27 conduct disordered and 16 comparison children and their mothers. Results indicated that: 1) these observations may yield very different data about child, and to a lesser extent, parent behavior, 2) parental affect in the clinic was related to their level of aversive behaviour in the home, 3) levels of both aversive and positive behavior for children and their mothers were correlated within each setting, 4) accuracy of diagnostic classifications made on the basis of the observational data were highest for comparison and conduct disordered children, but lowest for depressed children observed in the clinic, and 5) the inclusion of data on mothers' behavior increased classification accuracy for conduct disordered children only.     

Effects of Perceived Group Effectiveness and Group Role on Attributions of Group Performance1

Cadets at the U.S. Military Academy completed a questionnaire describing their experiences in Cadet Basic Training (CBT) and Cadet Field Training (CFT). Analyses of variance examined the impact of Group Role (Leader vs. Follower) and Perceived Group Effectiveness (High vs. Low) on group member perceptions of the extent to which each of six factors affected group performance. Significant main effects for Perceived Effectiveness were interpreted in terms of the egodefensive bias. Role main effects indicated that leaders tended to make stronger dispositional attributions than did followers. There were no signifcant Group Role × Perceived Effectiveness interaction effects. Findings support, in part, hypotheses concerning the operation of an attributional bias within the leader-member relationship.