Primary Stimulus Generalization Research Articles

Computational models of stimulus equivalence: An intersection for the study of symbolic behavior.

Stimulus equivalence is a central paradigm in the analysis of symbolic behavior, language, and cognition. It describes emergent relations between stimuli that were not explicitly trained and cannot be explained by primary stimulus generalization. In recent years, researchers have developed computational models to simulate the learning of equivalence relations. These models have been used to address primary theoretical and methodological issues in this field, such as exploring the underlying mechanisms that explain emergent equivalence relations and analyzing the effects of training and testing protocols on equivalence outcomes. Nonetheless, although these models build upon general learning principles, their operation is usually obscure for nonmodelers, and in the field of stimulus equivalence computational models have been developed with a variety of approaches, architectures, and algorithms that make it difficult to understand the scope and contributions of these tools. In this paper, we present the state of the art in computational modeling of stimulus equivalence. We seek to provide concise and accessible descriptions of the models' functioning and operation, highlight their main theoretical and methodological contributions, identify the existing software available for researchers to run experiments, and suggest future directions in the emergent field of computational modeling of stimulus equivalence.

Editorial: Basic and Translational Research on Stimulus–Stimulus Relations

One of the great challenges for a behavioral science is to provide an account of emergent stimulus–stimulus relations not explained by primary stimulus generalization. For example, the relation between the visual stimulus dog and the sound made when someone says “dog” is often referred to as arbitrary because the two stimuli have no point-to-point correspondence (one is a sound, the other a creature incapable of making the sound “dog”). In humans, through natural language training, these two stimuli are related (an activity) such that they may occasion similar responding. For example, a child suffering from a dog phobia may experience an increased heart rate and jump into the arms of a parent who says, at the front door of a friend’s house, “They have a dog,” just as he would if he saw the dog. This two-member class of arbitrarily related stimuli is expanded when the verbal response “perro” is related as equivalent to “dog” and, subsequently, hearing “They have a perro” elicits the same fear responding in the dog-phobic listener. Emergent stimulus relations have been of interest since the beginnings of experimental psychology (e.g., Anrep, 1923; Bass H Hull, 1939; Shipley, 1933) and since that time, an extensive taxonomy of the variety of stimulus–stimulus relations has been created (see Murphy, 2002; Zentall, Galizio, & Critchfield, 2002). The study of emergent relating behavior experienced a behavior-analytic renaissance, of sorts, in the 1970s when Murray Sidman dropped everything else and began publishing studies on what would come to be called stimulus equivalence (Sidman, 1971; Sidman & Cresson, 1973; Sidman, Cresson, & WillsonMorris, 1974). As most readers know, stimuli are related as equivalent when following If A Then B and If A Then C training, the individual, without further training, demonstrates that A1⁄4A, B1⁄4B, C1⁄4C, B1⁄4A, C1⁄4A, B1⁄4C, and C1⁄4B, typically in a conditional discrimination task where the first symbol serves as a sample stimulus and the second is selected from several available comparison stimuli (Sidman & Tailby, 1982). Substituting a dog for Stimulus A, “dog” for B, and “perro” for C, reveals why this research paradigm was quickly recognized as a means by which a behavior-analytic approach might be applied to the study of complex cognitive phenomena (e.g., Fields, Verhave, & Fath, 1984; Sidman, 1986). That is, an approach focused on identifying the necessary and sufficient conditions for producing emergent relating behavior. This special issue of the Journal of the Experimental Analysis of Behavior (JEAB) focuses on stimulus–stimulus relations. Understanding the varieties of relating behavior has generated an enormous amount of research in human and animal laboratories and the findings have generated new theories that have themselves occasioned additional investigations. As has so often been the case in our science, translational research findings have emerged and, in some circles, have proliferated. This special issue of JEAB offers an opportunity to look back upon what we know, what we are learning today, and to consider the ongoing potential of what has proven to be a fruitful research line. In what follows of this editorial, we walk that path.

Stimulus Equivalence, Generalization, and Contextual Stimulus Control in Verbal Classes

Stimulus generalization and contextual control affect the development of equivalence classes. Experiment 1 demonstrated primary stimulus generalization from the members of trained equivalence classes. Adults were taught to match six spoken Icelandic nouns and corresponding printed words and pictures to one another in computerized three-choice matching-to-sample tasks. Tests confirmed that six equivalence classes had formed. Without further training, plural forms of the stimuli were presented in tests for all matching performances. All participants demonstrated virtually errorless performances. In Experiment 2, classifications of the nouns used in Experiment 1 were brought under contextual control. Three nouns were feminine and three were masculine. The match-to-sample training taught participants to select a comparison of the same number as the sample (i.e., singular or plural) in the presence of contextual stimulus A regardless of noun gender. Concurrently, in the presence of contextual stimulus B, participants were taught to select a comparison of the same gender as the sample (i.e., feminine or masculine), regardless of number. Generalization was assessed using a card-sorting test. All participants eventually sorted the cards correctly into gender and number stimulus classes. When printed words used in training were replaced by their picture equivalents, participants demonstrated almost errorless performances.

Cultural differences in preferences for shapes.

It was predicted that since there is less sexual restraint in Jamaica the sex difference in shape preference should be larger for native adult Jamaicans than Caymanian adults. Pairs of drawings of a "female" and a "male" object, depicted according to the theory of sexual symbolism, were shown to 200 subjects, who indicated which of each pair they preferred. The larger sex difference found among Jamaicans was interpreted in terms of primary sexual stimulus generalization.

A note on the role of olfaction in taste aversion learning

A taste aversion was induced by the single or multiple pairing of saccharin and methotrexate. In one experiment the presence of saccharin in the environment of condtioned animals prior to the test trials resulted in an attenuation of the aversion, that is, facilitated extinction of the conditioned response. In a second experiment the consumption of plain water by conditioned animals was significantly reduced when animals were tested in the presence of other animals that were provided with saccharin, the CS solution. The data suggest that primary stimulus generalization in the form of olfactory cues can influence the manifestation of taste aversion behavior by decreasing the magnitude of the avoidance response or by decreasing the consumption of fluid by control animals.

Comparison of intradimensional and extradimensional shifts using geometric and symbolic stimuli

In two experiments, college students were required to make intradimensional (ID) or extradimensional (ED) shifts when potential confounding factors were eliminated through the use of a total change design and symbolic (word) stimuli. Results indicated that an ID shift was learned significantly faster than an ED shift, whether geometric or symbolic stimuli were employed. Original learning with both classes of stimuli was found to be comparable. Evidence was lacking for the hypothesis that a nonmediational process, such as primary stimulus generalization, accounted for ID shift superiority. The results were interpreted as supporting a two-stage mediational explanation of human discrimination learning.

Primary stimulus generalization effect in latent extinction of latent acquisition

After latent acquisition training placements to reward in the goalbox of a straight runway, Ss received latent extinction training placements to nonreward in either the runway goalbox or a distinctive goalbox. Control groups received either latent acquisition training only or neither type of training. Running speed data from a single test trial provided evidence for the operation of primary stimulus generalization in producing latent acquisition and latent extinction effects.

Perceptual and conceptual categorization in stimulus generalization.

Stimulus generalization was hypothesized to represent the outcome of a perceptual (for primary stimulus generalization) or conceptual (for secondary stimulus generalization) categorization process. Perception and conception were distinguished by differential speed and locus of action and by varying susceptibility to irrelevant and redundant information. Within a semantic generalization paradigm, S's right forearm muscle potentials to semantic and homographic generalization words were recorded. Time interval and stimulus display characteristics of the presentations of the generalization word were varied. Results indicated little support for the view of stimulus generalization as a categorization process. There was, however, support for the differential susceptibility of perception and conception to variations in stimulus display characteristics.

The nature of the stimulus in primary stimulus generalization.

The nature of the stimulus in primary stimulus generalization.

Primary stimulus generalization of the GSR as a function of objective and subjective definition of the stimulus dimension.

Primary stimulus generalization of the GSR as a function of objective and subjective definition of the stimulus dimension.

Mediational Processes in Primary Stimulus Generalization

Mediational Processes in Primary Stimulus Generalization

COMPOUND STIMULI, DRIVE STRENGTH, AND PRIMARY STIMULUS GENERALIZATION.

COMPOUND STIMULI, DRIVE STRENGTH, AND PRIMARY STIMULUS GENERALIZATION.

PRIMARY STIMULUS GENERALIZATION UNDER DIFFERENT PERCENTAGES OF REINFORCEMENT IN EYELID CONDITIONING.

PRIMARY STIMULUS GENERALIZATION UNDER DIFFERENT PERCENTAGES OF REINFORCEMENT IN EYELID CONDITIONING.

Primary stimulus generalization.

Primary stimulus generalization.

Primary stimulus generalization and secondary extinction as a function of strength of conditioning.

Primary stimulus generalization and secondary extinction as a function of strength of conditioning.

Primary stimulus generalization in discrimination learning as a function of numbers of trials and incidental cue differences.

Primary stimulus generalization in discrimination learning as a function of numbers of trials and incidental cue differences.

Primary and secondary stimulus generalization as related to intelligence level.

Primary and secondary stimulus generalization as related to intelligence level.

Primary stimulus generalization as a function of acquisition level in the cat.

Primary stimulus generalization as a function of acquisition level in the cat.

Primary stimulus generalization of the GSR under two conditions.

Primary stimulus generalization of the GSR under two conditions.

Primary stimulus generalization: a neurophysiological view.

Primary stimulus generalization: a neurophysiological view.