title: Eye tracking and pupillometry are indicators of dissociable latent decision processes.
abstract: Can you predict what people are going to do just by watching them? This is certainly difficult: it would require a clear mapping between observable indicators and unobservable cognitive states. In this report, we demonstrate how this is possible by monitoring eye gaze and pupil dilation, which predict dissociable biases during decision making. We quantified decision making using the drift diffusion model (DDM), which provides an algorithmic account of how evidence accumulation and response caution contribute to decisions through separate latent parameters of drift rate and decision threshold, respectively. We used a hierarchical Bayesian estimation approach to assess the single trial influence of observable physiological signals on these latent DDM parameters. Increased eye gaze dwell time specifically predicted an increased drift rate toward the fixated option, irrespective of the value of the option. In contrast, greater pupil dilation specifically predicted an increase in decision threshold during difficult decisions. These findings suggest that eye tracking and pupillometry reflect the operations of dissociated latent decision processes.
authors.affiliation: Department of Cognitive, Linguistic, and Psychological Sciences, Brown University.
authors.forename: James F
authors.initials: JF
authors.lastname: Cavanagh
authors.affiliation: Department of Cognitive, Linguistic, and Psychological Sciences, Brown University.
authors.forename: Thomas V
authors.initials: TV
authors.lastname: Wiecki
authors.affiliation: Department of Cognitive, Linguistic, and Psychological Sciences, Brown University.
authors.forename: Angad
authors.initials: A
authors.lastname: Kochar
authors.affiliation: Department of Cognitive, Linguistic, and Psychological Sciences, Brown University.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Frank
mesh_terms: D001288:Attention / Q000502:physiology*; D003198:Computer Simulation; D003220:Conflict, Psychological; D003657:Decision Making / Q000502:physiology*; D053483:Eye Movement Measurements; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008960:Models, Psychological; D011680:Pupil / Q000502:physiology*; D055815:Young Adult