Cognitive and perceptual influences on visual line bisection: Psychophysical and chronometric analyses of pseudoneglect

Mark E. McCourt, Curt Olafson

Research output: Contribution to journalArticle

101 Citations (Scopus)

Abstract

Perceptual and cognitive influences on line bisection were isolated using a tachistoscopic forced-choice paradigm. Pretransected lines were presented for 150 msec at four orientations (|, -, / and \). Subjects made either 'left-right' (for -, /, and \ lines) or 'above-below' (for |, / and \ lines) discriminations in response to each line stimulus, depending upon perceived transector location relative to veridical line midpoint. Median response time and point of subjective equality (P.S.E.) were computed for each treatment condition. P.S.E.s in 'left-right' conditions were significantly left of veridical; response time maxima were similarly displaced. Azimuthal pseudoneglect was greatest for horizontal lines. P.S.E.s in 'above-below' conditions were displaced above veridical, and response time maxima were similarly displaced. Altitudinal pseudoneglect was greatest for negative diagonal lines (\). Azimuthal pseudoneglect significantly exceeded altitudinal pseudoneglect. 'Left-right' responses (mean = 478.3 msec) were significantly faster than 'above-below' responses (mean = 504.6 msec). We conclude that scanning eye and/or gross limb movements do not account for pseudoneglect, and that a significant component must be purely perceptual. Chronometric and psychometric measures of pseudoneglect are in remarkable agreement. The effects of altitudinal and azimuthal pseudoneglect are neither separable nor additive, suggesting the existence of independent mechanisms governing the allocation of spatial attention to objects of differing orientation. The slopes of the psychometric functions for lines of cardinal orientation are significantly steeper than for diagonal lines, which may reflect a processing conflict between these putatively independent mechanisms at diagonal line orientations. Decision context significantly modulates the magnitude of pseudoneglect for physically identical stimuli, perhaps reflecting the selective differential engagement of the vertical or horizontal attentional mechanisms. There are significant individual differences in line bisection performance, even in a very homogeneous sample of strongly right-handed subjects.

Original languageEnglish (US)
Pages (from-to)369-380
Number of pages12
JournalNeuropsychologia
Volume35
Issue number3
DOIs
StatePublished - Feb 7 1997

Fingerprint

Reaction Time
Psychometrics
Individuality
Extremities
Therapeutics
Conflict (Psychology)

Keywords

  • Chronometric
  • Line bisection
  • Pseudoneglect
  • Psychophysical
  • Spatial attention

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience
  • Behavioral Neuroscience

Cite this

Cognitive and perceptual influences on visual line bisection : Psychophysical and chronometric analyses of pseudoneglect. / McCourt, Mark E.; Olafson, Curt.

In: Neuropsychologia, Vol. 35, No. 3, 07.02.1997, p. 369-380.

Research output: Contribution to journalArticle

@article{0d4ef8906a5644cabc8889eda64c0232,
title = "Cognitive and perceptual influences on visual line bisection: Psychophysical and chronometric analyses of pseudoneglect",
abstract = "Perceptual and cognitive influences on line bisection were isolated using a tachistoscopic forced-choice paradigm. Pretransected lines were presented for 150 msec at four orientations (|, -, / and \). Subjects made either 'left-right' (for -, /, and \ lines) or 'above-below' (for |, / and \ lines) discriminations in response to each line stimulus, depending upon perceived transector location relative to veridical line midpoint. Median response time and point of subjective equality (P.S.E.) were computed for each treatment condition. P.S.E.s in 'left-right' conditions were significantly left of veridical; response time maxima were similarly displaced. Azimuthal pseudoneglect was greatest for horizontal lines. P.S.E.s in 'above-below' conditions were displaced above veridical, and response time maxima were similarly displaced. Altitudinal pseudoneglect was greatest for negative diagonal lines (\). Azimuthal pseudoneglect significantly exceeded altitudinal pseudoneglect. 'Left-right' responses (mean = 478.3 msec) were significantly faster than 'above-below' responses (mean = 504.6 msec). We conclude that scanning eye and/or gross limb movements do not account for pseudoneglect, and that a significant component must be purely perceptual. Chronometric and psychometric measures of pseudoneglect are in remarkable agreement. The effects of altitudinal and azimuthal pseudoneglect are neither separable nor additive, suggesting the existence of independent mechanisms governing the allocation of spatial attention to objects of differing orientation. The slopes of the psychometric functions for lines of cardinal orientation are significantly steeper than for diagonal lines, which may reflect a processing conflict between these putatively independent mechanisms at diagonal line orientations. Decision context significantly modulates the magnitude of pseudoneglect for physically identical stimuli, perhaps reflecting the selective differential engagement of the vertical or horizontal attentional mechanisms. There are significant individual differences in line bisection performance, even in a very homogeneous sample of strongly right-handed subjects.",
keywords = "Chronometric, Line bisection, Pseudoneglect, Psychophysical, Spatial attention",
author = "McCourt, {Mark E.} and Curt Olafson",
year = "1997",
month = "2",
day = "7",
doi = "10.1016/S0028-3932(96)00143-1",
language = "English (US)",
volume = "35",
pages = "369--380",
journal = "Neuropsychologia",
issn = "0028-3932",
publisher = "Elsevier Limited",
number = "3",

}

TY - JOUR

T1 - Cognitive and perceptual influences on visual line bisection

T2 - Psychophysical and chronometric analyses of pseudoneglect

AU - McCourt, Mark E.

AU - Olafson, Curt

PY - 1997/2/7

Y1 - 1997/2/7

N2 - Perceptual and cognitive influences on line bisection were isolated using a tachistoscopic forced-choice paradigm. Pretransected lines were presented for 150 msec at four orientations (|, -, / and \). Subjects made either 'left-right' (for -, /, and \ lines) or 'above-below' (for |, / and \ lines) discriminations in response to each line stimulus, depending upon perceived transector location relative to veridical line midpoint. Median response time and point of subjective equality (P.S.E.) were computed for each treatment condition. P.S.E.s in 'left-right' conditions were significantly left of veridical; response time maxima were similarly displaced. Azimuthal pseudoneglect was greatest for horizontal lines. P.S.E.s in 'above-below' conditions were displaced above veridical, and response time maxima were similarly displaced. Altitudinal pseudoneglect was greatest for negative diagonal lines (\). Azimuthal pseudoneglect significantly exceeded altitudinal pseudoneglect. 'Left-right' responses (mean = 478.3 msec) were significantly faster than 'above-below' responses (mean = 504.6 msec). We conclude that scanning eye and/or gross limb movements do not account for pseudoneglect, and that a significant component must be purely perceptual. Chronometric and psychometric measures of pseudoneglect are in remarkable agreement. The effects of altitudinal and azimuthal pseudoneglect are neither separable nor additive, suggesting the existence of independent mechanisms governing the allocation of spatial attention to objects of differing orientation. The slopes of the psychometric functions for lines of cardinal orientation are significantly steeper than for diagonal lines, which may reflect a processing conflict between these putatively independent mechanisms at diagonal line orientations. Decision context significantly modulates the magnitude of pseudoneglect for physically identical stimuli, perhaps reflecting the selective differential engagement of the vertical or horizontal attentional mechanisms. There are significant individual differences in line bisection performance, even in a very homogeneous sample of strongly right-handed subjects.

AB - Perceptual and cognitive influences on line bisection were isolated using a tachistoscopic forced-choice paradigm. Pretransected lines were presented for 150 msec at four orientations (|, -, / and \). Subjects made either 'left-right' (for -, /, and \ lines) or 'above-below' (for |, / and \ lines) discriminations in response to each line stimulus, depending upon perceived transector location relative to veridical line midpoint. Median response time and point of subjective equality (P.S.E.) were computed for each treatment condition. P.S.E.s in 'left-right' conditions were significantly left of veridical; response time maxima were similarly displaced. Azimuthal pseudoneglect was greatest for horizontal lines. P.S.E.s in 'above-below' conditions were displaced above veridical, and response time maxima were similarly displaced. Altitudinal pseudoneglect was greatest for negative diagonal lines (\). Azimuthal pseudoneglect significantly exceeded altitudinal pseudoneglect. 'Left-right' responses (mean = 478.3 msec) were significantly faster than 'above-below' responses (mean = 504.6 msec). We conclude that scanning eye and/or gross limb movements do not account for pseudoneglect, and that a significant component must be purely perceptual. Chronometric and psychometric measures of pseudoneglect are in remarkable agreement. The effects of altitudinal and azimuthal pseudoneglect are neither separable nor additive, suggesting the existence of independent mechanisms governing the allocation of spatial attention to objects of differing orientation. The slopes of the psychometric functions for lines of cardinal orientation are significantly steeper than for diagonal lines, which may reflect a processing conflict between these putatively independent mechanisms at diagonal line orientations. Decision context significantly modulates the magnitude of pseudoneglect for physically identical stimuli, perhaps reflecting the selective differential engagement of the vertical or horizontal attentional mechanisms. There are significant individual differences in line bisection performance, even in a very homogeneous sample of strongly right-handed subjects.

KW - Chronometric

KW - Line bisection

KW - Pseudoneglect

KW - Psychophysical

KW - Spatial attention

UR - http://www.scopus.com/inward/record.url?scp=0031058552&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031058552&partnerID=8YFLogxK

U2 - 10.1016/S0028-3932(96)00143-1

DO - 10.1016/S0028-3932(96)00143-1

M3 - Article

C2 - 9051685

AN - SCOPUS:0031058552

VL - 35

SP - 369

EP - 380

JO - Neuropsychologia

JF - Neuropsychologia

SN - 0028-3932

IS - 3

ER -