A comparison of the effects of partial reinforcement schedules using a within-subject serial autoshaping procedure

Three experiments, each using a single group of pigeons, are reported. In Experiment 1 subjects were initially trained with two stimuli, one of which was always followed by food, the other being reinforced according to a 50% partial reinforcement schedule. Subsequently a serial procedure was adopted in which an additional stimulus, C, was consistently followed by the partially reinforced CS. A second additional stimulus, A, was followed on half of its occurrences by the continuously reinforced CS, its remaining presentations being followed by nothing. The rate of autoshaped keypecking was substantially greater during A than during C. In the remaining experiments subjects received first-order conditioning with a single stimulus that was either partially (Experiment 2) or continuously (Experiment 3) reinforced. The stimuli A and C were then again introduced for serial autoshaping. Stimulus A was occasionally paired with the CS and occasionally followed by nothing, whereas stimulus C was always followed by the CS. As in Experiment 1, the rate of responding during A was greater than during C. It is proposed that one influence on the rate of autoshaped keypecking during a CS is the accuracy with which the immediate consequences of that CS are predicted.     

The recovery of structure from motion: no evidence for a special link with the convergent disparity mechanism

Convergent and divergent stereo mechanisms were compared in their ability to recover structure from motion. Contrary to a recent result reported by Richards and Lieberman, no difference in their performance was found; both mechanisms appeared equally capable of supporting the perception of good structure from motion. Possible reasons for the disparate results are discussed.     

Consequences of socially sharing emotions: testing the emotion-response congruency hypothesis

We test the emotion-response congruency hypothesis, which predicts that the consequences of socially sharing one's negative emotions depend on the congruency between the shared emotion and the response that is obtained from the interaction partner. Experiment 1a shows that the response that people prefer is dependent on the specific emotion shared. Experiment 1b, however, reveals that the responses that interaction partners provide do not differ across emotions. Yet, and crucially, Experiment 2 shows that the outcomes of sharing are affected by the congruency between the response that people receive and the emotion they share, thus supporting the emotion-response congruency hypothesis. Copyright © 2006 John Wiley & Sons, Ltd.