Predicting the Extension of Equivalence Classes From Primary Generalization Gradients: The Merger of Equivalence Classes and Perceptual Classes

Abstract

In Experiment 1, 6 college students were given generalization tests using 25 line lengths as samples with a long line, a short line, and a "neither" option as comparisons. The neither option was to be used if a sample did not go with the other comparisons. Then, four-member equivalence classes were formed. Class 1 included three nonsense words and the short line. Class 2 included three other nonsense words and the long line. After repeating the generalization test for line length, additional tests were conducted using members of the equivalence classes (i.e., nonsense words and lines) as comparisons and intermediate-length lines as samples. All Class 2 comparisons were selected in the presence of the test lines that also evoked the selection of the long line in the generalization test that had been given before equivalence class formation. Class 1 yielded complementary findings. Thus, the preclass primary generalization gradient predicted which test lines acted as members of each equivalence class. Regardless of using comparisons that were nonsense words or lines, the post-class-formation gradients overlapped, showing the substitutability of class members. Experiment 2 assessed the discriminability of the intermediate-length test lines from the Class 1 (shortest) and Class 2 (longest) lines. The test lines that functioned as members of an equivalence class were discriminable from the line that was a member of the same class by training. Thus, these test lines also acted as members of a dimensionally defined class of "long" or "short" lines. Extension of an equivalence class, then, involved its merger with a dimensionally defined class, which converted a close-ended class to an open-ended class. These data suggest a means of predicting class membership in naturally occurring categories.

The Long-Term Retention Of Generalized Equivalence Classes

“…Consistent with preVious studies (Fields et aI., 1991;1997), this experiment demonstrated the generalization of equivalence relations to dimensional variants of class members. This procedure differed from those in previous studies in showing generalization along the dimension of hue, and in showing the generalization of relations involving stimuli which had been presented as elements of complex samples during training.…”

“…It was found that as the physical disparity between dimensional variants and class members systematically increased, the proportion of class-consistent responses declined (see also Fields, Reeve, Adams, & Verhave, 1991;and Fields, Adams, Buffington, Yang, & Verhave, 1996). Fields, Reeve, Adams, Brown, and Verhave (1997) used generalization gradients obtained prior to an equivalence test to predict to which dimensional variants stimulus class membership would generalize, and observed considerable overlap between pre-class and post-class gradients. These findings have led Fields et al (1997) to propose that the generalization of stimulus equivalence is a means by which conceptual classes merge with perceptual classes.…”

“…Fields, Reeve, Adams, Brown, and Verhave (1997) used generalization gradients obtained prior to an equivalence test to predict to which dimensional variants stimulus class membership would generalize, and observed considerable overlap between pre-class and post-class gradients. These findings have led Fields et al (1997) to propose that the generalization of stimulus equivalence is a means by which conceptual classes merge with perceptual classes. Equivalence classes may be conceptualized as openended, polymorphous classes, with virtually no limit to the number of stimuli comprising a given class (Fields et aI., 1997).…”

The Generalization and Retention of Equivalence Relations in Adults With Mental Retardation

“…The generalization of equivalence relations to a range of novel stimuli has been reported a number of times in studies utilizing verbally competent, adult human subjects (e.g., Fields, Adams, Buffington, Yang, & Verhave, 1996;Fields & Reeve, 2001;Fields, Reeve, Adams, Brown, & Verhave, 1997;Fields, Reeve, Adams, & Verhave, 1991;Rehfeldt, 2003;Rehfeldt & Hayes, 2000;Rehfeldt, Hayes, & Steele, 1998). This body of research has revealed that equivalence relations may generalize to dimensional variants that are physically similar along some dimension to an original training stimulus.…”

Tactual Equivalence Class Formation and Tactual-to-Visual Cross-Modal Transfer

“…An equivalence class should function as a network that occasions the transfer of new responses among class members or the generalization of equivalence-based responding to other stimuli (Barnes, Browne, Smeets, & Roche, 1995;Fields, Reeve , Adams, Brown , & Verhave , 1997;Sidman , 1994) . The cross-modal general ization tests provided one such assessment in the current experiment.…”