Prior probability biases perceptual choices by modulating the accumulation rate, rather than the baseline, of decision evidence

Diaz, Jessica A. and Pisauro, M. Andrea and Delis, Ioannis and Philiastides, Marios G. (2024) Prior probability biases perceptual choices by modulating the accumulation rate, rather than the baseline, of decision evidence. Imaging Neuroscience, 2. ISSN 2837-6056

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Abstract

The prior probability of an upcoming stimulus has been shown to influence the formation of perceptual decisions. Computationally, these effects have typically been attributed to changes in the starting point (i.e., baseline) of evidence accumulation in sequential sampling models. More recently, it has also been proposed that prior probability might additionally lead to changes in the rate of evidence accumulation. Here, we introduce a neurally-informed behavioural modelling approach to understand whether prior probability influences the starting point, the rate of evidence accumulation or both. To this end, we employ a well-established visual object categorisation task for which two neural components underpinning participants’ choices have been characterised using single-trial analysis of the electroencephalogram. These components are reliable measures of trial-by-trial variability in the quality of the relevant decision evidence, which we use to constrain the estimation of a hierarchical drift diffusion model of perceptual choice. We find that, unlike previous computational accounts, constraining the model with the endogenous variability in the relevant decision evidence results in prior probability effects being explained primarily by changes in the rate of evidence accumulation rather than changes in the starting point or a combination of both. Ultimately, our neurally-informed modelling approach helps disambiguate the mechanistic effect of prior probability on perceptual decision formation, suggesting that prior probability biases primarily the interpretation of sensory evidence towards the most likely stimulus.

Item Type:	Article
Identification Number:	10.1162/imag_a_00338
Dates:	Date Event 21 September 2024 Accepted 15 October 2024 Published Online
Uncontrolled Keywords:	prior probability, decision making, electroencephalography, hierarchical drift diffusion model, neurally-informed modeling
Subjects:	CAH04 - psychology > CAH04-01 - psychology > CAH04-01-01 - psychology (non-specific)
Divisions:	Faculty of Business, Law and Social Sciences > College of Psychology
Depositing User:	Gemma Tonks
Date Deposited:	20 Dec 2024 12:19
Last Modified:	20 Dec 2024 12:19
URI:	https://www.open-access.bcu.ac.uk/id/eprint/16039

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