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PLoS Comput Biol. 2016 Feb 11;12(2):e1004667. doi: 10.1371/journal.pcbi.1004667. eCollection 2016 Feb.

Non-monotonic Temporal-Weighting Indicates a Dynamically Modulated Evidence-Integration Mechanism.

Author information

1
School of Psychology, Tel-Aviv University, Tel-Aviv, Israel.
2
The Cohn Institute for the History and Philosophy of Science and Ideas, Tel-Aviv University, Tel-Aviv, Israel.
3
Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel.

Abstract

Perceptual decisions are thought to be mediated by a mechanism of sequential sampling and integration of noisy evidence whose temporal weighting profile affects the decision quality. To examine temporal weighting, participants were presented with two brightness-fluctuating disks for 1, 2 or 3 seconds and were requested to choose the overall brighter disk at the end of each trial. By employing a signal-perturbation method, which deploys across trials a set of systematically controlled temporal dispersions of the same overall signal, we were able to quantify the participants' temporal weighting profile. Results indicate that, for intervals of 1 or 2 sec, participants exhibit a primacy-bias. However, for longer stimuli (3-sec) the temporal weighting profile is non-monotonic, with concurrent primacy and recency, which is inconsistent with the predictions of previously suggested computational models of perceptual decision-making (drift-diffusion and Ornstein-Uhlenbeck processes). We propose a novel, dynamic variant of the leaky-competing accumulator model as a potential account for this finding, and we discuss potential neural mechanisms.

PMID:
26866598
PMCID:
PMC4750938
DOI:
10.1371/journal.pcbi.1004667
[Indexed for MEDLINE]
Free PMC Article

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