Decision criterion dynamics in animals performing an auditory detection task

Dick, F., Mill, R.W., Alves-Pinto, A. and Sumner, C.J. ORCID: 0000-0002-2573-7418, 2014. Decision criterion dynamics in animals performing an auditory detection task. PLoS ONE, 9 (12): e114076. ISSN 1932-6203

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Abstract

Classical signal detection theory attributes bias in perceptual decisions to a threshold criterion, against which sensory excitation is compared. The optimal criterion setting depends on the signal level, which may vary over time, and about which the subject is naïve. Consequently, the subject must optimise its threshold by responding appropriately to feedback. Here a series of experiments was conducted, and a computational model applied, to determine how the decision bias of the ferret in an auditory signal detection task tracks changes in the stimulus level. The time scales of criterion dynamics were investigated by means of a yes-no signal-in-noise detection task, in which trials were grouped into blocks that alternately contained easy- and hard-to-detect signals. The responses of the ferrets implied both long- and short-term criterion dynamics. The animals exhibited a bias in favour of responding “yes” during blocks of harder trials, and vice versa. Moreover, the outcome of each single trial had a strong influence on the decision at the next trial. We demonstrate that the single-trial and block-level changes in bias are a manifestation of the same criterion update policy by fitting a model, in which the criterion is shifted by fixed amounts according to the outcome of the previous trial and decays strongly towards a resting value. The apparent block-level stabilisation of bias arises as the probabilities of outcomes and shifts on single trials mutually interact to establish equilibrium. To gain an intuition into how stable criterion distributions arise from specific parameter sets we develop a Markov model which accounts for the dynamic effects of criterion shifts. Our approach provides a framework for investigating the dynamics of decisions at different timescales in other species (e.g., humans) and in other psychological domains (e.g., vision, memory)

Item Type:	Journal article
Publication Title:	PLoS ONE
Creators:	Dick, F., Mill, R.W., Alves-Pinto, A. and Sumner, C.J.
Publisher:	Public Library of Science
Date:	8 December 2014
Volume:	9
Number:	12
ISSN:	1932-6203
Identifiers:	Number Type 10.1371/journal.pone.0114076 DOI
Rights:	Copyright © 2014 Mill et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Divisions:	Schools > School of Social Sciences
Record created by:	Jonathan Gallacher
Date Added:	27 Feb 2019 13:33
Last Modified:	27 Feb 2019 13:33
URI:	https://irep.ntu.ac.uk/id/eprint/35830

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