Social categorisation and stimulus equivalence: the competition between relations

Abstract

This thesis focused on examining the competition between relations among stimuli across multiple testing contexts, through the stimulus equivalence paradigm. The Watt et al. (1991) paper was the prime inspiration for this research project. In the Watt et al. study, participants were initially trained to demonstrate the prerequisite conditional discrimination relations for the emergence of three three-member equivalence classes. Each of these experimenter-defined classes consisted of a stereotypical Northern Irish ‘Catholic’ name (A stimulus), a three-letter nonsense syllable (B stimulus), and a stereotypical Northern Irish ‘Protestant’ symbol (within a Northern Irish context) (Cstimulus). During probes for the expected emergent relations between the C and Astimuli participants were given the opportunity to respond to a novel stereotypical Northern Irish ‘Protestant’ name (X stimulus). The results demonstrated that Northern Irish participants were more likely to select the novel X stimuli during C-A equivalence probes, while English participants readily demonstrated the expected emergent C-Aequivalence-based response selection. Chapter 2 provides an overview of the papers that have cited the original Watt et al. study in the three decades since its publication. Chapter 3 contained six experiments, the first of which examined the current relevance of the original study. This replication demonstrated that the novel ‘Protestant’ names still exerted a disruptive effect on the emergence of the expected C-A equivalence-based response selections, prompting further experiments. Subsequent experiments manipulated the presence / absence of the disruptive stimuli to examine the effect on the incidence of the expected C-Aequivalence-based response selections. Chapter 4 expanded this line of research by examining the role of the properties of novelty and pre-experimental history on the emergence of equivalence-based response selections among abstract stimuli. Results demonstrated that both these variables contributed to response selections during emergent relation probes. Chapter 5 explored competing relations between stimuli within equivalence classes established using the Watt et al. procedure. The results demonstrated that there was a hierarchy of competing relations within the equivalence classes. Chapter 6 examined the influence of social functions on the hierarchy of competing relations. It was found that the function assigned to one component of a relation could influence the probability of response selection in the hierarchy of relations. Collectively, the findings across all studies are discussed in relation to a variety of topics that all come under the umbrella of the effects of how differing strengths of multiple relations within equivalence classes influence novel responding.

Date of Award	May 2026
Original language	English
Supervisor	Mickey Keenan (Supervisor) & Stephen Gallagher (Supervisor)