Expectancy and frequency effects on perceptual and motor systems in choice reaction time

Three experiments investigated the effects of expectancy and stimulus frequency in character classification and identification tasks. Both expectancy and frequency were found to have effects on overall response latency, but the two factors had different patterns of interaction with two other experimental variables. The effect of visual quality was larger for low-frequency stimuli than for high-frequency stimuli, whereas the effect of quality was independent of expectancy. The effect of S-R compatibility was more strongly influenced by whether a stimulus was expected than by the frequency of the stimulus. The results suggest that expectancy and frequency have somewhat different effects on human information processing mechanisms. Expectancy allows temporary preparation for a specific S-R pair in response selection processes, but it has no effect on perceptual processes. Stimulus frequency, on the other hand, influences the efficiency of both perceptual and response selection processes. The overall effect of stimulus probability may be interpreted as having as components both expectancy and frequency effects.     

Family Sculpting: I. Some doubts and some possibilities

Family sculpting is reviewed within the context of general doubts that confront family therapy, in particular the need for a certain act of faith in therapy, and the search for some sort of underlying theory. Family sculpting is most often used in reference to the psychoanalytic tradition of family therapy, but here the case is made for more serious attention to structural approaches. The potential of family sculpting is further explored in a number of other respects: its concreteness, its portrayal of ambiguity and its use with students, workers and other groups.     

Crisis, taboos and careers guidance

The relevance of the idea of 'crisis' for careers and careers guidance is examined, together with some of the critical responses that have been made to recent crises. It is argued that careers guidance generally responds to such challenges by seeing them as external problems rather than as changes which may alter its very assumptions and methods. Two particular taboos are noted in this context concerning the value of work and of working for an organisation. The questioning of these taboos leads to four models of alternative careers: the Uncareer, the Guerilla Career, the Cop-Out Career, and the Non-Career. These forms of career raise the broader issues of order and disorder within careers, with their associated implications for careers guidance.     

Change mechanisms in cognitive therapy of a simple phobia: Logical analysis and empirical hypothesis testing

The effectiveness of two hypothesized change mechanisms in cognitive therapy was investigated: logical analysis and empirical hypothesis testing. Thirty-eight spider phobics, as determined by performance on a behavioral avoidance test, were randomly assigned to either one of these two conditions or to a no-treatment control condition. Subjects participated in three group sessions. Outcome phobia questionnaire data suggested that both mechanisms produced desirable changes in a short period of time, with stronger evidence that logical analysis was superior to the control. Outcome from the behavior avoidance test and self-efficacy ratings failed to reach statistical significance but the trends were in the direction of positive change. Results are discussed in terms of the tripartite response dessynchrony hypothesis. Suggestions for future process research in cognitive therapy are provided.William O'Donohue, Ph.D., is an assistant professor of psychology at Northern Illinois University.Jeff Szymanski is a graduate student in clinical psychology at Northern Illinois University.The authors would like to thank Christine Casselles, Melissa McKelvie, Thomas M. Brown, Jill C. Rudman, Bonnie Schrieber, Amy Ray, Anne Valle, Lisa Herold, Jacqueline Ryan, Heather Barta, and Angela Leek for their assistance in this project. Moreover, the authors are grateful to Sol Feldman and Jane Fisher for their comments on an earlier version of this paper.     

Killing, letting die, and withdrawing aid

One of the aims of this article is to contribute to the identification of the empirical criteria governing the use of the concepts of killing and letting die. I will not attempt a comprehensive analysis of the concepts but will limit the inquiry to certain problematic cases -- namely, cases involving the removal or withdrawal of life-supporting aid or protection. The analysis of these cases will, however, shed light on the criteria for distinguishing killing and letting die in other cases as well. My overall aims in the article are partly constructive and partly skeptical. I hope to advance our understanding of the nature of the distinction between killing and letting die. This, I believe, will enable us to defend the moral relevance of the distinction against certain objections -- in particular, objections that claim that the distinction fails to coincide with commonsense moral intuitions. Yet I will suggest that, as we get clearer about the nature of the distinction and the sources of its intuitive appeal, it may seem that the intuitions it supports are not so well grounded as one could wish.     

Reversal of the preference reversal phenomenon

The widely replicated preference reversal phenomenon (PRP) violates most theories of decision under risk. People exhibiting PRP choose a safe bet (with a large chance of a small gain) over a long shot (with a small chance of a larger gain). But, when bidding to buy or sell each bet, they bid more for the long shot. Surprisingly, in Experiment 1, a new opposite reversal pattern (NPRP) was found: Safe bets typically received larger bids than long shots and reversals were far more frequent when the long shot was chosen. In Experiment 2, NPRP was found for $100 expected value bets, but PRP occurred for bets with $3 expected values. The task characteristics apparently necessary to produce NPRP are (1) bids in the form of maximum buying prices, (2) possibility of loss in bidding, but not in choice, and (3) large payoffs. It is argued that wealth effects predicted by expected utility theory are too small to explain NPRP. Instead, it is hypothesized that a contingent decision process underlies the shift in reveral patterns and that aspiration levels exert increased influence in bidding to buy when payoffs are large.     

Bias produced by fast guessing in distribution-based tests of race models

A comparison involving cumulative probability distributions of reaction time (RT) has been used to test race models of the redundancy gain observed in certain divided-attention paradigms. It has beenpointed out, however, that the presence of fast guesses wouldinterfera with this test, biasing it to accept race models. The present paper reports simulations carried out to determine the size of the bias introduced by fast guesses. In absolute terms, this bias can be quite large— exceeding 175 msec in some conditions. Simulations indicate that the bias increases with the percentage of fast guesses and with the latency difference between the lower tails of guess and nonguess RT distributions. Discarding and rerunning errors reduces bias somewhat, but a more elaborate “kill-the-twin” procedure reduces it much more.     

Acquisition and retention of control of instrumental behavior by a cue-signaling airblast: How specific are conditioned anticipations?

The conditioned state evoked by a CS that had been paired with an aversive airblast was assessed by superimposing the CS on baselines of instrumental responding. The first experiment used a shock avoidance baseline; CS-airblast pairings were administered on the baseline, with the shock avoidance schedule in effect. The CS that signaled airblast came, over trails, to accelerate shock avoidance responding. As further CS-airblast trials were administered, however, the acceleratory effect of the CS decreased, producing an inverted-U-shaped acquisition curve. A second experiment used off-baseline CS-airblast conditioning, and the CS was tested on both shock avoidance and water reinforcement baselines. After 20 CS-airblast pairings the CS accelerated shock avoidance and suppressed water-reinforced responding. After 10o pairings, however, the acceleratory effect on shock avoidance was much attenuated, although the suppressions of the water-reinforced behavior did not differ between 20- and 100-trial groups. Two further experiments examined retention, over a 45-day interval, of the attenuation of the CS's effects on shock avoidance. Over the retention interval, this attenuation disappeared. It was, however, reinstated by giving the animals “reminder” presentations of the airblast. These results are interpreted as representing systematic changes in the specificity of the conditioned state evoked by a Pavlovian CS.     

Goodness-of-fit tests for models of latency and choice

A goodness-of-fit test based on the maximum likelihood criterion is derived for use in evaluating models of choice reaction time that predict choice probabilities and means and variances of latency. Special cases of the test involving models that predict only one or two of these statistics are considered and shown to be asymptotically identical to the traditional goodness-of-fit tests appropriate for these special cases.