From Attention to Choice: Quantifying How Gaze Bias Modulates Value Using a Drift-Diffusion Model

Abstract

Organisms make choices that reflect how they value the options presented to them. While research has established that value plays a critical role in decision making, Schonberg et al. presents novel research suggesting that the intrinsic value of goods can be modulated by cue-approach training (presenting an item concurrently with an irrelevant auditory cue signaling participants to make a motor response), with choice and willingness-to-pay (WTP) serving as measures of preference shift. Yet the mechanism for how the preference shift occurs as a result of cue-approach training remains unclear. To quantify the relationship between gaze bias and choice, Krajbich et al. introduces a drift-diffusion model (DDM) where fixations affect the value comparison process through the introduction of a temporary drift bias toward the fixated item. Using the model, Kraijbich performed experiments demonstrating that eye fixations affect value: people tend to choose the item they spend the most time looking at. This, Krajibich’s model quantifies the effect of eye fixations on value. The hypothesis of this thesis is that the Krajbich valuation effect mediates the Schonberg preference change: cue approach training affects eye movement and this affects valuation. I investigate this account by fitting the Krajbich DDM model to Schonberg data demonstrating how cue-approach training shifts preference. This thesis proposes a quantitative mechanism explaining how valuation changes as measured by WTP and choice when there is increased eye movement specificity towards the trained items. The thesis also examines behavioral health applications of using eye-tracking data to understand choice.