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Article
Peer Reviewed

Categorization in Environments that Change when People Learn

Proceedings of the Annual Meeting of the Cognitive Science Society, Volume 44 (2022)

Most studies of human category learning involve category structures that do not change, or that change in a way that is independent of people's categorization behavior. We consider the situation in which successful category learning causes categories to change. In an experiment, participants learned from feedback whether animals are healthy or diseased. Once their categorization accuracy was near-perfect, the category structure changed so that different animals became diseased. Based on exploratory data analysis and the application of two category learning models, we argue that, once they detect a category change, people retain what they have learned about healthy animals, but reset what they have learned about diseased animals. We discuss future modeling goals and emphasize the need for learning models to study situations in which people's behavior impacts the dynamics of the environment in which learning takes place.

Cover page: Categorization in Environments that Change when People Learn

Creative Commons 'BY' version 4.0 license

Article
Peer Reviewed

Adaptive design optimization for a Mnemonic Similarity Task

UC Irvine Previously Published Works (2022)

The Mnemonic Similarity Task (MST: Stark et al., 2019) is a modified recognition memory task designed to place strong demand on pattern separation. The sensitivity and reliability of the MST make it an extremely valuable tool in clinical settings, where it has been used to identify hippocampal dysfunction associated with healthy aging, dementia, schizophrenia, depression, and other disorders. As with any test used in a clinical setting, it is especially important for the MST to be administered as efficiently as possible. We apply adaptive design optimization methods (Lesmes et al., 2015; Myung et al., 2013) to optimize the presentation of test stimuli in accordance with previous responses. This optimization is based on a signal-detection model of an individual's memory capabilities and decision-making processes. We demonstrate that the adaptive design optimization approach generally reduces the number of test stimuli needed to provide these measures.

Article

Bayesian graphical modeling with the circular drift diffusion model

UC Irvine Previously Published Works (2023)

The circular drift-diffusion model (CDDM) is a sequential sampling model designed to account for decisions and response times in decision-making tasks with a circular set of choice alternatives. We present and demonstrate a fully Bayesian implementation and extension of the CDDM. This development allows researchers to apply the CDDM to data from complex experiments and draw conclusions about targeted hypotheses. The Bayesian implementation relies on a custom JAGS module. We describe the module and demonstrate its adequacy through a simulation study. We then illustrate the advantages of the implementation by revisiting data from a continuous orientation judgment task. We develop a graphical model for the analysis that is based on the CDDM, but extends it with hierarchical and latent-mixture structures.We then demonstrate how these extensions are used to accommodate the design of the experiment and to implement psychological assumptions about individual differences, the difficulty of different stimulus conditions, and the impact of cues on decision making. Finally, we demonstrate how the computational Bayesian inference enabled by JAGS allows these assumptions to be tested and addresses psychological research questions about people's decision making.

Creative Commons 'BY-SA' version 4.0 license

Article
Peer Reviewed

Bayesian Graphical Modeling with the Circular Drift Diffusion Model

UC Irvine Previously Published Works (2023)

The circular drift-diffusion model (CDDM) is a sequential sampling model designed to account for decisions and response times in decision-making tasks with a circular set of choice alternatives. We present and demonstrate a fully Bayesian implementation and extension of the CDDM. This development allows researchers to apply the CDDM to data from complex experiments and draw conclusions about targeted hypotheses. The Bayesian implementation relies on a custom JAGS module. We describe the module and demonstrate its adequacy through a simulation study. We then illustrate the advantages of the implementation by revisiting data from a continuous orientation judgment task. We develop a graphical model for the analysis that is based on the CDDM but extends it with hierarchical and latent-mixture structures. We then demonstrate how these extensions are used to accommodate the design of the experiment and to implement psychological assumptions about individual differences, the difficulty of different stimulus conditions, and the impact of cues on decision making. Finally, we demonstrate how the computational Bayesian inference enabled by JAGS allows these assumptions to be tested and addresses psychological research questions about people’s decision making.