The acquisition of observing.

Pigeons were exposed to stimuli correlated with the presence or absence of a variable-interval 60-second schedule of reinforcement only while they depressed a crossbar or "perch." In the first experiment, the stimuli were different tilts of a line displayed on the key. When the difference in brightness between the line and the background (salience) was maximal, seven of eight birds acquired the discrimination, but when the difference was reduced by 50%, only one succeeded. In the second experiment, wavelength of chamber illumination served as the relevant dimension. Neither experiment showed a large effect attributable to the magnitude of the difference (disparity) between the positive and the negative stimulus. Individual differences in time spent observing were positively correlated with level of discrimination in the presence of the stimuli. All birds produced the positive stimulus for a greater proportion of the available time than they did the negative stimulus. This may be the mechanism that provides selective reinforcement of observing. Finally, the formation of a discrimination was analyzed in terms of changes in the proportion of time spent in contact with the discriminative stimuli.     

The role of beliefs in goal dynamics: prolegomena to a constructive theory of intentions

In this article we strive to provide a detailed and principled analysis of the role of beliefs in goal processing—that is, the cognitive transition that leads from a mere desire to a proper intention. The resulting model of belief-based goal processing has also relevant consequences for the analysis of intentions, and constitutes the necessary core of a constructive theory of intentions, i.e. a framework that not only analyzes what an intention is, but also explains how it becomes what it is. We discuss similarities and differences between our approach and other standard accounts of intention, in particular Bratman’s planning theory. The aim here is to question and refine the conceptual foundations of many theories of intentional action: as a consequence, although our analysis is not formal in itself, it is ultimately meant to have deep consequences for formal models of intentional agency.     

Differentiating the effects of self-control and self-esteem on reactions to mortality salience

Whereas many previous studies suggest that self-esteem may buffer against the psychological threat of death, recent research has begun to suggest that self-control also may serve as a buffer. Two studies examined the possibility that dispositional self-control uniquely predicts responses to mortality salience, above and beyond self-esteem. In Study 1, an initial exercise in emotion regulation increased subsequent accessibility of death thoughts. In Study 2, mortality salience increased worldview defense. Both of these effects were moderated by dispositional self-control, such that the effects occurred among participants with low but not high self-control. More importantly, these moderating effects were observed over and above the moderating effects of self-esteem. Findings suggest that self-control may serve as an important and unique buffer against thoughts of death.