Predicting the extension of equivalence classes from primary generalization gradients: the merger of equivalence classes and perceptual classes.

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.

Interactions among emergent relations during equivalence class formation.

The interactions among symmetry, transitivity, and equivalence tests during the formation of 3-member equivalence classes were studied with 14 college students. After training AB and BC, a test with BA, CB, AC, and CA was conducted concurrently. Failure led to serial testing with probes for CA equivalence, BA symmetry, CA equivalence, CB symmetry, CA equivalence, AC transitivity, and CA equivalence.

Stimulus generalization and equivalence classes: a model for natural categories.

Two three-member classes were formed by training AB and BC using a conditional discrimination procedure. The A and B stimuli were nonsense syllables, and the C stimuli were sets of "short" or "long" lines. To test for equivalence, C1 or C2 was presented as a sample with A1 and A2 as comparisons.

The effects of nodality on the formation of equivalence classes.

A four-member equivalence class (A----B----C----D) can be formed by training AB, BC, and CD. The nodal stimuli, B and C, mediate all of the derivative (transitive and equivalence) relations in the class. The derivative relations AC, CA, BD, and DB are separated by one node, whereas AD and DA are separated by two nodes.

The structure of equivalence classes.

THE STRUCTURE OF EQUIVALENCE CLASSES CAN BE COMPLETELY DESCRIBED BY FOUR PARAMETERS: class size, number of nodes, the distribution of "singles" among nodes, and directionality of training. Class size refers to the number of stimuli in a class. Nodes are stimuli linked by training to at least two other stimuli.

Stimulus equivalence and transitive associations: A methodological analysis.

When a number of two-stimulus relations are established through training within a set of stimuli, other two-stimulus relations often emerge in the same set without direct training. These, termed "transitive stimulus relations," have been demonstrated with a variety of visual and auditory stimuli. The phenomenon has served as a behavioral model for explaining the emergence of rudimentary comprehension and reading skills, and the development of generative syntactic repertoires.

TOWARDS AN EMPIRICAL CALCULUS OF REINFORCEMENT VALUE.

Only one of two keys reinforces the subject with food. This key can assume one of two colors, each associated with a different fixed-ratio schedule for obtaining reinforcement. The function of the second key is to permit the animal to switch from the long schedule to the short schedule.

The functional properties of a time out from an avoidance schedule.

Investigations are reported of some of the discriminative (cue) and reinforcing properties of stimuli (TO(av)) correlated with the discontinuation of a free-operant avoidance schedule. After several unsuccessful initial attempts to demonstrate the positively reinforcing effect of TO(av), a special technique was developed. The subjects were trained by means of a free-operant avoidance procedure to press a lever and postpone electric shock; by pressing a second lever, they could produce a cue correlated with the TO(av) period.

Technique for differential reinforcement of rate of avoidance responding.

A new avoidance conditioning procedure generates high rates of responding compared with previously used procedures. The effect of manipulation of one of the important temporal parameters in the procedure is reported.