Contextual effects in speed perception may occur at an early stage of processing

Daniel H. Baker, Erich W. Graf

Research output: Contribution to journalArticle

Abstract

How does nearby motion affect the perceived speed of a target region? When a central drifting Gabor patch is surrounded by translating noise, its speed can be misperceived over a fourfold range. Typically, when a surround moves in the same direction, perceived centre speed is reduced; for opposite-direction surrounds it increases. Measuring this illusion for a variety of surround properties reveals that the motion context effects are a saturating function of surround speed (Experiment I) and contrast (Experiment II). Our analyses indicate that the effects are consistent with a subtractive process, rather than with speed being averaged over area. In Experiment III we exploit known properties of the motion system to ask where these surround effects impact. Using 2D plaid stimuli, we find that surround-induced shifts in perceived speed of one plaid component produce substantial shifts in perceived plaid direction. This indicates that surrounds exert their influence early in processing, before pattern motion direction is computed. These findings relate to ongoing investigations of surround suppression for direction discrimination, and are consistent with single-cell findings of direction-tuned suppressive and facilitatory interactions in primary visual cortex (V1).
Original languageEnglish
Pages (from-to)193-201
Number of pages9
JournalVision Research
Volume50
Issue number2
DOIs
Publication statusPublished - 25 Jan 2010

Fingerprint

Visual Cortex
Noise
Direction compound
Discrimination (Psychology)

Bibliographical note

NOTICE: this is the author’s version of a work that was accepted for publication in Vision Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Baker, Daniel H. and Graf, Erich W (2010). Contextual effects in speed perception may occur at an early stage of processing. Vision Research, 50 (2), pp. 193-201. DOI 10.1016/j.visres.2009.11.011

Keywords

  • speed perception
  • surround suppression
  • facilitation
  • plaid

Cite this

Baker, Daniel H. ; Graf, Erich W. / Contextual effects in speed perception may occur at an early stage of processing. In: Vision Research. 2010 ; Vol. 50, No. 2. pp. 193-201.
@article{c0cf4b48f9484335bd012991f4131126,
title = "Contextual effects in speed perception may occur at an early stage of processing",
abstract = "How does nearby motion affect the perceived speed of a target region? When a central drifting Gabor patch is surrounded by translating noise, its speed can be misperceived over a fourfold range. Typically, when a surround moves in the same direction, perceived centre speed is reduced; for opposite-direction surrounds it increases. Measuring this illusion for a variety of surround properties reveals that the motion context effects are a saturating function of surround speed (Experiment I) and contrast (Experiment II). Our analyses indicate that the effects are consistent with a subtractive process, rather than with speed being averaged over area. In Experiment III we exploit known properties of the motion system to ask where these surround effects impact. Using 2D plaid stimuli, we find that surround-induced shifts in perceived speed of one plaid component produce substantial shifts in perceived plaid direction. This indicates that surrounds exert their influence early in processing, before pattern motion direction is computed. These findings relate to ongoing investigations of surround suppression for direction discrimination, and are consistent with single-cell findings of direction-tuned suppressive and facilitatory interactions in primary visual cortex (V1).",
keywords = "speed perception, surround suppression, facilitation, plaid",
author = "Baker, {Daniel H.} and Graf, {Erich W.}",
note = "NOTICE: this is the author’s version of a work that was accepted for publication in Vision Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Baker, Daniel H. and Graf, Erich W (2010). Contextual effects in speed perception may occur at an early stage of processing. Vision Research, 50 (2), pp. 193-201. DOI 10.1016/j.visres.2009.11.011",
year = "2010",
month = "1",
day = "25",
doi = "10.1016/j.visres.2009.11.011",
language = "English",
volume = "50",
pages = "193--201",
journal = "Vision Research",
issn = "0042-6989",
publisher = "Elsevier",
number = "2",

}

Contextual effects in speed perception may occur at an early stage of processing. / Baker, Daniel H.; Graf, Erich W.

In: Vision Research, Vol. 50, No. 2, 25.01.2010, p. 193-201.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Contextual effects in speed perception may occur at an early stage of processing

AU - Baker, Daniel H.

AU - Graf, Erich W.

N1 - NOTICE: this is the author’s version of a work that was accepted for publication in Vision Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Baker, Daniel H. and Graf, Erich W (2010). Contextual effects in speed perception may occur at an early stage of processing. Vision Research, 50 (2), pp. 193-201. DOI 10.1016/j.visres.2009.11.011

PY - 2010/1/25

Y1 - 2010/1/25

N2 - How does nearby motion affect the perceived speed of a target region? When a central drifting Gabor patch is surrounded by translating noise, its speed can be misperceived over a fourfold range. Typically, when a surround moves in the same direction, perceived centre speed is reduced; for opposite-direction surrounds it increases. Measuring this illusion for a variety of surround properties reveals that the motion context effects are a saturating function of surround speed (Experiment I) and contrast (Experiment II). Our analyses indicate that the effects are consistent with a subtractive process, rather than with speed being averaged over area. In Experiment III we exploit known properties of the motion system to ask where these surround effects impact. Using 2D plaid stimuli, we find that surround-induced shifts in perceived speed of one plaid component produce substantial shifts in perceived plaid direction. This indicates that surrounds exert their influence early in processing, before pattern motion direction is computed. These findings relate to ongoing investigations of surround suppression for direction discrimination, and are consistent with single-cell findings of direction-tuned suppressive and facilitatory interactions in primary visual cortex (V1).

AB - How does nearby motion affect the perceived speed of a target region? When a central drifting Gabor patch is surrounded by translating noise, its speed can be misperceived over a fourfold range. Typically, when a surround moves in the same direction, perceived centre speed is reduced; for opposite-direction surrounds it increases. Measuring this illusion for a variety of surround properties reveals that the motion context effects are a saturating function of surround speed (Experiment I) and contrast (Experiment II). Our analyses indicate that the effects are consistent with a subtractive process, rather than with speed being averaged over area. In Experiment III we exploit known properties of the motion system to ask where these surround effects impact. Using 2D plaid stimuli, we find that surround-induced shifts in perceived speed of one plaid component produce substantial shifts in perceived plaid direction. This indicates that surrounds exert their influence early in processing, before pattern motion direction is computed. These findings relate to ongoing investigations of surround suppression for direction discrimination, and are consistent with single-cell findings of direction-tuned suppressive and facilitatory interactions in primary visual cortex (V1).

KW - speed perception

KW - surround suppression

KW - facilitation

KW - plaid

UR - http://www.scopus.com/inward/record.url?scp=72749119635&partnerID=8YFLogxK

U2 - 10.1016/j.visres.2009.11.011

DO - 10.1016/j.visres.2009.11.011

M3 - Article

VL - 50

SP - 193

EP - 201

JO - Vision Research

JF - Vision Research

SN - 0042-6989

IS - 2

ER -