Voluntary stimulus generalization as a three-category judgment process

Abstract

Human Ss were asked to heft a 150-g weight and were required to identify it in a test series of weights, ranging in value from 100 to 200 g, with 25-g steps. Following each test response, each S was asked to rate the weight he had just lifted on a 7-point scale of heaviness, with 1 being very light, 4 neither light nor heavy, and 7 being very heavy. Results showed that Ss chose the stimulus weight closest to adaptation level (125 g) as the original training stimulus more often than the 150-g weight itself. Support was noted for adaptation-level theory. Further, analysis of rating data yielded information as to why Ss rejected a given stimulus as not the original. Three gradients of response, “too light,” “same,” and “too heavy,” were drawn, showing this voluntary generalization task to be a three-category judgment process.