The Organization of Hypothesis-Testing Behavior in Concept-Identification Tasks

Abstract

The major purposes of this paper were twofold: to test extensively the generality and validity of the conclusion by Fishbein, Benton, Osborne, and Wise that in concept-identification tasks, the stimulus dimensions play an important organizational role in the way Ss test and to determine the extent to which the number of dimensions and values within each dimension affects selective memory loss from Trial n to Trial n+ 1. In the Fishbein et al. study, Ss were run in either three-dimension, two-value, or six-dimension, twovalue, successive discrimination-learning tasks. A modification of the blank-trials technique of Levine2 was so employed that on each outcome trial, Ss received information about only one hypothesis, i.e. one value of one dimension. These authors found that following an error on Trial 1, the probability of Ss testing on Trial 2 a hypothesis that lay along the same stimulus dimension as their Trial 1 hypothesis was significantly greater than chance. Does this behavior occur when simultaneous discrimination tasks are used? More importantly, does the dimension continue to organize Ss' behavior beyond the first two outcome trials? The second major set of questions arose from the fact that when the blank-trials technique is utilized, S is informed on each outcome trial about both the correctness of the hypothesis he held during the no-outcome trials and the correctness of other hypotheses, i.e. the other values of the chosen stimulus. Levine has shown that in