Equivalence Class Formation and Attitudes Toward Neurodevelopmental Disabilities

Stigma related to neurodevelopmental disabilities can lead to negative experiences, such as social isolation and unjust disparities across life domains. Despite efforts, interventions have been largely ineffective in altering implicit attitudes toward individuals with developmental disabilities. Basic behavior analytic research has discovered a reflective relationship between equivalence class formation and implicit attitudes, as measured by the Implicit Association Test (IAT). Research has also confirmed that performance on the IAT can be altered through equivalence class reorganization. However, this has not yet been evaluated in the context of socially loaded stimuli, which generally fail to produce typical equivalence class formation when class members belong to opposing social categories. This dissertation examined the relationship between implicit attitudes and equivalence formation, or resistance to formation, using socially loaded stimuli related to neurodevelopmental disabilities. Experiment 1 assessed whether pre-existing bias, measured by the IAT, predicted equivalence class formation. Participants completed a baseline IAT, followed by conditional discrimination training and tests for equivalence class formation. Participants completed a baseline IAT, followed by conditional discrimination training and tests for equivalence class formation using either medical model terminology (stigma-congruent) or disability accepting terminology (stigma-incongruent) class members. An IAT post-assessment was then administered to evaluate changes in bias and examine potential differences in outcomes between the two stimulus sets. Experiment 2 expanded upon the analysis by assessing stimulus blocking as a potential mechanisms underlying the development and maintenance of stigma. Experiment 3 integrated both the IAT and the equivalence blocking procedure into the equivalence model of social categorization to evaluate whether pre-existing bias influenced equivalence class formation or evidence of the blocking effect. It also examined whether stigma-congruent versus stigma-incongruent class members produced differential outcomes in both the formation of equivalence classes and implicit bias. Results of experiment 1 indicated that participant baseline IAT performance was strongly linked to equivalence class formation (namely transitivity and equivalence tests) and changes in implicit bias, but no differences were found between participants who received training with stigma-congruent relative to stigma-incongruent training. Differential outcomes were found in Experiment 2, where those trained with arbitrary base-class stimuli and socially loaded X stimuli performed better on tests for X-equivalence class formation relative to those trained with all arbitrary stimuli or primarily socially loaded stimuli. Whereas pre-existing bias was the strongest predictor of emergent relations test outcomes, this was not the case in experiment 3 when IAT attributes were used in conditional discrimination training and testing phases. However, pre-existing bias did predict both IAT post-test performance and overall IAT change scores. The current experiments offer important insights into the formation and maintenance of harmful stereotypes related to developmental disabilities and the role of derived relational responding and stimulus blocking in maintaining or weakening harmful stereotypes.