Reply to silberberg and ziriax

Silberberg and Ziriax (1985) report that a modification of Vaughan's (1981) procedure produces results inconsistent with melioration (the position advocated by Vaughan) but consistent with a process they term molecular maximizing. Here it is argued that the theory of molecular maximization is not sufficiently unambiguous that researchers other than the developers can test its predictions, and that in any case none of the data presented by Silberberg and Ziriax are both clearly consistent with molecular maximization and inconsistent with melioration.     

Utility maximization and melioration: Internalities in individual choice

How do people go about choosing between alternatives in relatively simple settings? This study explores some of the variables that past work suggests may be relevant. Volunteer subjects worked for money in six procedures in which the probability of a payment from either of two alternatives was 1.0, but the rate of pay (i.e. the speed with which a payment was delivered or the size of the payment) interacted with the subjects recent allocation of choices, which we define as the ‘internalities’. Because of the internalities, choosing the currently more profitable alternative did not maximize total earnings. Subjects were more likely to fail to maximize when the interaction between present pay and past choices was spread over longer sequences of choices, or when the reward variable was the speed, rather than the value, of each payment. Subjects often disregarded the internalities and were instead guided by the current yields of the two alternatives, which is a frequently observed tendency, called ‘melioration’, in experiments on choices by animals. The tendency toward melioration was only partially counteracted by explicit instructions on how to maximize earnings. We discuss a theoretical framework for melioration that postulates both motivational and cognitive sources.     

Using PsyScope for demonstrations and student-designed experiments in cognitive psychology courses

We describe a plan for integrating an experimental control language, PsyScope, into under-graduate laboratory exercises of perceptual and cognitive experiments on Macintosh computers. PsyScope is a powerful and versatile system with which students can modify standard research paradigms and execute experiments of their own design, thus facilitating student-initiated independent research. Data are summarized with a general-purpose program, PsySquash, for import into Statview or SuperAnova for further analysis. This system provides an effective means of implementing student projects.     

Application of modal logic to programming

The modal logician's notion of possible world and the computer scientist's notion of state of a machine provide a point of commonality which can form the foundation of a logic of action. Extending ordinary modal logic with the calculus of binary relations leads to a very natural logic for describing the behavior of computer programs.This research was supported by NSF Grant No. MSC - 7804338.     

The effect of modification of expressive displays on vicarious emotional arousal

Several recent experiments have demonstrated that modulation of the facial expressive response is accompanied by changes in autonomic arousal and subjective response to painful stimuli. The present study asked whether facial self-regulation may also bring about changes in covert vicarious emotional experience. Three groups of subjects were exposed to a videotaped model displaying intermittent pain to shock in a differential vicarious autonomic conditioning paradigm. Subjects in the inhibit and amplify groups were asked, respectively, (a) to inhibit their facial muscles or (b) to pose a facial response of pain when the model was shocked. It was predicted that the inhibit group would show less autonomic arousal to the model's expressive display (empathy) and less conditioning (as measured by skin conductance and heart rate change), and the amplify group more empathy and conditioning, than a third group who was given no facial instruction. In fact, the amplify group showed more skin conductance arousal, heart rate acceleration, and activity in response to the model's expressive display of pain than did the other two groups (which were not different from each other), but no more autonomic or facial conditioning. The overall pattern of physiological data is interpreted as generally supportive of a facial feedback theory of emotion: where significant between-groups' differences were obtained in facial activity, as in vicarious instigation, autonomic arousal differences also emerged; where no expressive differences were obtained, as in vicarious conditioning, no differences in autonomic arousal were found.     

Control of fixation duration in visual search and memory search: another look

In visual search a variable delay (up to 150 msec) between the beginning of each fixation and the onset of a search stimulus reduces the time (oculomotor latency) between stimulus onset and the subject's next saccadic eye movement. Two hypotheses for this effect of stimulus onset delay (SOD) were compared: first, process monitoring, that SOD simply serves as a warning interval to facilitate saccadic responses; and second, preprogramming, that saccades are preprogrammed at short SODs. In the first experiment SOD produced a decline in oculomotor latency in search similar to that seen in previous studies. In the second and third experiments, the size of the memory set in a Sternberg memory search paradigm was varied, or a mask flanking some of the search stimuli was used, to vary the processing time of each stimulus. Partial preprogramming of saccades at short delays would predict that increasing the processing time of individual stimuli would increase oculomotor latency at only short SODs. However, oculomotor latency increased equally at all SODs. In this search task, then, the SODs appeared to facilitate saccade initiation.