Relative motion, not polarity, breaks 'surface tension'

Erik Blaser, Z. Vidnyánszky, Thomas Papathomas

Research output: Contribution to journalArticle

Abstract

Purpose. To investigate the rules that underlie visual surface integration and segmentation. Methods. Observers viewed motion transparency: two fields of superimposed, drifting dots. One field (of black dots) drifted rightward, the other (white dots) leftward. This stimulus was used as the adaptor in a motion aftereffect (MAE) paradigm. Results 1. When tested with a static field of black and white dots, no MAE was reported; i.e. the expected polarity-contingent MAE was not expressed. Any polarity-contingent MAE would have to have shown up as a transparent MAE (that is, with the black dots in the test field undergoing illusory motion to the left simultaneously with the superimposed white dots undergoing illusory rightward motion); such effects are notoriously difficult to produce (because, we hypothesize, such a stimulus is treated as a single surface, which is assigned a single direction of motion). However, we reasoned that if we facilitated the segmentation of the black and white surfaces during testing, the MAE could be expressed. Results 2. Using the same adaptor described above, we then introduced a relative motion cue into the test (white dots moving upward, black downward). Now any horizontal polarity-contingent MAE would be added to these vertical motion vectors, producing a, in this case, clockwise deflection of the perceived shear axis. Four observers perceived tilts of 4-8 deg. Conclusions. Polarity alone was not sufficient for segmentation of the two surfaces (a likely necessary condition if each are to move in different directions), and hence the polarity-contingent MAE was either actively suppressed, or too weak to break this 'surface tension'. Only when a powerful relative motion segmentation cue was added was the surface tension broken, and the polarity-contingent MAE expressed. Ongoing studies are quantifying the contribution and interaction of such surface segmentation cues.

Original languageEnglish
JournalJournal of Vision
Volume2
Issue number7
DOIs
Publication statusPublished - 2002

Fingerprint

Surface Tension
Cues

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Relative motion, not polarity, breaks 'surface tension'. / Blaser, Erik; Vidnyánszky, Z.; Papathomas, Thomas.

In: Journal of Vision, Vol. 2, No. 7, 2002.

Research output: Contribution to journalArticle

Blaser, Erik ; Vidnyánszky, Z. ; Papathomas, Thomas. / Relative motion, not polarity, breaks 'surface tension'. In: Journal of Vision. 2002 ; Vol. 2, No. 7.
@article{ff9f0d9fd84348b68f9981dbafc400a8,
title = "Relative motion, not polarity, breaks 'surface tension'",
abstract = "Purpose. To investigate the rules that underlie visual surface integration and segmentation. Methods. Observers viewed motion transparency: two fields of superimposed, drifting dots. One field (of black dots) drifted rightward, the other (white dots) leftward. This stimulus was used as the adaptor in a motion aftereffect (MAE) paradigm. Results 1. When tested with a static field of black and white dots, no MAE was reported; i.e. the expected polarity-contingent MAE was not expressed. Any polarity-contingent MAE would have to have shown up as a transparent MAE (that is, with the black dots in the test field undergoing illusory motion to the left simultaneously with the superimposed white dots undergoing illusory rightward motion); such effects are notoriously difficult to produce (because, we hypothesize, such a stimulus is treated as a single surface, which is assigned a single direction of motion). However, we reasoned that if we facilitated the segmentation of the black and white surfaces during testing, the MAE could be expressed. Results 2. Using the same adaptor described above, we then introduced a relative motion cue into the test (white dots moving upward, black downward). Now any horizontal polarity-contingent MAE would be added to these vertical motion vectors, producing a, in this case, clockwise deflection of the perceived shear axis. Four observers perceived tilts of 4-8 deg. Conclusions. Polarity alone was not sufficient for segmentation of the two surfaces (a likely necessary condition if each are to move in different directions), and hence the polarity-contingent MAE was either actively suppressed, or too weak to break this 'surface tension'. Only when a powerful relative motion segmentation cue was added was the surface tension broken, and the polarity-contingent MAE expressed. Ongoing studies are quantifying the contribution and interaction of such surface segmentation cues.",
author = "Erik Blaser and Z. Vidny{\'a}nszky and Thomas Papathomas",
year = "2002",
doi = "10.1167/2.7.92",
language = "English",
volume = "2",
journal = "Journal of Vision",
issn = "1534-7362",
publisher = "Association for Research in Vision and Ophthalmology Inc.",
number = "7",

}

TY - JOUR

T1 - Relative motion, not polarity, breaks 'surface tension'

AU - Blaser, Erik

AU - Vidnyánszky, Z.

AU - Papathomas, Thomas

PY - 2002

Y1 - 2002

N2 - Purpose. To investigate the rules that underlie visual surface integration and segmentation. Methods. Observers viewed motion transparency: two fields of superimposed, drifting dots. One field (of black dots) drifted rightward, the other (white dots) leftward. This stimulus was used as the adaptor in a motion aftereffect (MAE) paradigm. Results 1. When tested with a static field of black and white dots, no MAE was reported; i.e. the expected polarity-contingent MAE was not expressed. Any polarity-contingent MAE would have to have shown up as a transparent MAE (that is, with the black dots in the test field undergoing illusory motion to the left simultaneously with the superimposed white dots undergoing illusory rightward motion); such effects are notoriously difficult to produce (because, we hypothesize, such a stimulus is treated as a single surface, which is assigned a single direction of motion). However, we reasoned that if we facilitated the segmentation of the black and white surfaces during testing, the MAE could be expressed. Results 2. Using the same adaptor described above, we then introduced a relative motion cue into the test (white dots moving upward, black downward). Now any horizontal polarity-contingent MAE would be added to these vertical motion vectors, producing a, in this case, clockwise deflection of the perceived shear axis. Four observers perceived tilts of 4-8 deg. Conclusions. Polarity alone was not sufficient for segmentation of the two surfaces (a likely necessary condition if each are to move in different directions), and hence the polarity-contingent MAE was either actively suppressed, or too weak to break this 'surface tension'. Only when a powerful relative motion segmentation cue was added was the surface tension broken, and the polarity-contingent MAE expressed. Ongoing studies are quantifying the contribution and interaction of such surface segmentation cues.

AB - Purpose. To investigate the rules that underlie visual surface integration and segmentation. Methods. Observers viewed motion transparency: two fields of superimposed, drifting dots. One field (of black dots) drifted rightward, the other (white dots) leftward. This stimulus was used as the adaptor in a motion aftereffect (MAE) paradigm. Results 1. When tested with a static field of black and white dots, no MAE was reported; i.e. the expected polarity-contingent MAE was not expressed. Any polarity-contingent MAE would have to have shown up as a transparent MAE (that is, with the black dots in the test field undergoing illusory motion to the left simultaneously with the superimposed white dots undergoing illusory rightward motion); such effects are notoriously difficult to produce (because, we hypothesize, such a stimulus is treated as a single surface, which is assigned a single direction of motion). However, we reasoned that if we facilitated the segmentation of the black and white surfaces during testing, the MAE could be expressed. Results 2. Using the same adaptor described above, we then introduced a relative motion cue into the test (white dots moving upward, black downward). Now any horizontal polarity-contingent MAE would be added to these vertical motion vectors, producing a, in this case, clockwise deflection of the perceived shear axis. Four observers perceived tilts of 4-8 deg. Conclusions. Polarity alone was not sufficient for segmentation of the two surfaces (a likely necessary condition if each are to move in different directions), and hence the polarity-contingent MAE was either actively suppressed, or too weak to break this 'surface tension'. Only when a powerful relative motion segmentation cue was added was the surface tension broken, and the polarity-contingent MAE expressed. Ongoing studies are quantifying the contribution and interaction of such surface segmentation cues.

UR - http://www.scopus.com/inward/record.url?scp=4243179070&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=4243179070&partnerID=8YFLogxK

U2 - 10.1167/2.7.92

DO - 10.1167/2.7.92

M3 - Article

AN - SCOPUS:4243179070

VL - 2

JO - Journal of Vision

JF - Journal of Vision

SN - 1534-7362

IS - 7

ER -