On the determinants of induction in responding for sucrose when food pellet reinforcement is upcoming

Rats' rates of leverpressing for low-concentration liquid-sucrose reinforcers in the first half of an experimental session increase when food pellet, rather than sucrose, reinforcers will be available in the second half. Experiment 1 determined that this induction effect was the outcome of food pellet reinforcement's increasing response rates, not of continued sucrose reinforcement's decreasing them. Experiments 2 and 3 showed that induction was primarily controlled by the conditions of reinforcement in the current session, not by those in the previous one. Experiment 4 showed little evidence that the induction was the outcome of Pavlovian processes. These results suggest that induction may occur because of processes operating at the level of the entire session. They also provide a link to a seemingly related area of study: contrast effects. Some of the results are consistent with what is known about contrast effects, but there are also several, yet unexplained differences.     

A Comparison of Rorschach Responses Between Negro and White College Students

Abstract

David, Henry P. and Brengelmann, J.C., (eds.). Perspectives In Personality Research. New York: Springer, Inc., 1960. 370 pp. $7.50. Reviewed by Kenneth R. Wurtz

Gottsegen, Monroe G. and Gottsegen, Gloria B. Professional School Psychology. New York: Grune &; Stratton, 1960, Pp. 292, $7.75. Reviewed by Henry L. Levy

Klopfer, Walter G. The Psychological Report: Use and Communication of Psychological Findings. New York: Grune &; Stratton, 1960. Pp. ix and 146. Reviewed by Dale S. Higbee     

Delay discounting of different commodities II: confirmatory analyses

Delay discounting occurs when individuals are increasingly willing to accept less than the full amount of something to receive it immediately as the delay to the full amount increases. Previous research has reported different "domains" of commodities, with discounting in one domain not being informative about discounting in another. In the present study, 283 participants completed a delay-discounting task with 1 of 2 sets of 5 commodities identical to those used in previous research (Weatherly, Terrell, & Derenne, 2010). Confirmatory factor analyses determined that the observed discounting conformed to previously reported domains. Also replicated was finding that discounting differs both as a function of commodity and how the commodity is framed. These results provide strong support for the idea that temporal decisions made about certain consequences may not necessarily be informative about how an individual will make decisions about other consequences. Also, the framing of the decision can significantly influence observed levels of discounting, potentially clouding interpretation.