Perceptual biases are inconsistent with Bayesian encoding of speed in the human visual system. / Hassan, Omar; Hammett, Steve.

In: Journal of Vision, Vol. 15, No. 2, 9, 06.02.2015, p. 1-9.

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Perceptual biases are inconsistent with Bayesian encoding of speed in the human visual system. / Hassan, Omar; Hammett, Steve.

In: Journal of Vision, Vol. 15, No. 2, 9, 06.02.2015, p. 1-9.

Research output: Contribution to journalArticlepeer-review

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@article{facbd87ae1654bd4bf5ce3229b3c50e4,
title = "Perceptual biases are inconsistent with Bayesian encoding of speed in the human visual system",
abstract = "The notion that Bayesian processes are fundamental to brain function and sensory processing has recently received much support, and a number of Bayesian accounts of how the brain encodes the speed of moving objects have been proposed that challenge earlier mechanistic models. We measured the perceived speed of low contrast patterns at both low (2.5 cd m{\`A}2) and high (25 cd m{\`A}2) luminance in order to assess these competing models of how the human visual system encodes speed. At both luminance levels low contrast stimuli are perceptually biased such that they appear slower at slow (, 8 Hz) speeds but faster at higher (16 Hz) speeds. However, we find that the reversal of the perceptual bias from under- to overestimation occurred at slower speeds at low luminance. We also found that the bias was greater at slow speeds at high luminance but greater at fast speeds at low luminance. Moreover, discrimination thresholds were found to be similar at high and low luminance. These findings can be predicted by models in which speed is encoded by the relative activity within two broadly tuned temporal channels but are inconsistent with Bayesian models of speed encoding. We conclude that Bayesian processes cannot adequately account for speed encoding in the human visual system.",
author = "Omar Hassan and Steve Hammett",
year = "2015",
month = feb,
day = "6",
doi = "10.1167/15.2.9",
language = "English",
volume = "15",
pages = "1--9",
journal = "Journal of Vision",
issn = "1534-7362",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "2",

}

RIS

TY - JOUR

T1 - Perceptual biases are inconsistent with Bayesian encoding of speed in the human visual system

AU - Hassan, Omar

AU - Hammett, Steve

PY - 2015/2/6

Y1 - 2015/2/6

N2 - The notion that Bayesian processes are fundamental to brain function and sensory processing has recently received much support, and a number of Bayesian accounts of how the brain encodes the speed of moving objects have been proposed that challenge earlier mechanistic models. We measured the perceived speed of low contrast patterns at both low (2.5 cd mÀ2) and high (25 cd mÀ2) luminance in order to assess these competing models of how the human visual system encodes speed. At both luminance levels low contrast stimuli are perceptually biased such that they appear slower at slow (, 8 Hz) speeds but faster at higher (16 Hz) speeds. However, we find that the reversal of the perceptual bias from under- to overestimation occurred at slower speeds at low luminance. We also found that the bias was greater at slow speeds at high luminance but greater at fast speeds at low luminance. Moreover, discrimination thresholds were found to be similar at high and low luminance. These findings can be predicted by models in which speed is encoded by the relative activity within two broadly tuned temporal channels but are inconsistent with Bayesian models of speed encoding. We conclude that Bayesian processes cannot adequately account for speed encoding in the human visual system.

AB - The notion that Bayesian processes are fundamental to brain function and sensory processing has recently received much support, and a number of Bayesian accounts of how the brain encodes the speed of moving objects have been proposed that challenge earlier mechanistic models. We measured the perceived speed of low contrast patterns at both low (2.5 cd mÀ2) and high (25 cd mÀ2) luminance in order to assess these competing models of how the human visual system encodes speed. At both luminance levels low contrast stimuli are perceptually biased such that they appear slower at slow (, 8 Hz) speeds but faster at higher (16 Hz) speeds. However, we find that the reversal of the perceptual bias from under- to overestimation occurred at slower speeds at low luminance. We also found that the bias was greater at slow speeds at high luminance but greater at fast speeds at low luminance. Moreover, discrimination thresholds were found to be similar at high and low luminance. These findings can be predicted by models in which speed is encoded by the relative activity within two broadly tuned temporal channels but are inconsistent with Bayesian models of speed encoding. We conclude that Bayesian processes cannot adequately account for speed encoding in the human visual system.

U2 - 10.1167/15.2.9

DO - 10.1167/15.2.9

M3 - Article

VL - 15

SP - 1

EP - 9

JO - Journal of Vision

JF - Journal of Vision

SN - 1534-7362

IS - 2

M1 - 9

ER -