Spatiotemporal and luminance contrast properties of symmetry perception

Rebecca Sharman, Elena Gheorghiu

Research output: Contribution to journalSpecial issue

2 Citations (Scopus)
4 Downloads (Pure)

Abstract

Recent studies have shown that limiting the lifetime of pattern elements improves symmetry detection, potentially by increasing the number of element locations. Here, we investigate how spatial relocation, luminance contrast modulation and lifetime duration of elements affect symmetry perception in dynamic stimuli. Stimuli were dynamic dot-patterns containing varying amounts of symmetry about a vertical axis. Symmetrical matched-pairs were:(i) relocated to multiple successive, but random locations (ie, multiple locations condition);(ii) relocated between the same two locations (ie, two locations condition);(iii) not, relocated, but their luminance contrast was modulated at different temporal frequencies (ie, one location condition), and (iv) not relocated, but a single pattern was presented at full contrast (ie, static condition). In the dynamic conditions, we varied the elements’ lifetime duration and temporal frequency of contrast modulation. We measured symmetry detection thresholds using a two-interval forced choice procedure. Our results show improved performance for the multiple locations condition compared to two-location and static conditions, suggesting a cumulative process whereby weak symmetry information is integrated by spatiotemporal filters to increase overall symmetry signal strength. Performance also improved for the static, contrast modulated patterns, but this was explained by a reduction in perceived density. This suggests that different mechanisms mediate symmetry detection in dynamic stimuli and static contrast modulated patterns.
Original languageEnglish
Article number220
Number of pages14
JournalSymmetry
Volume10
Issue number6
DOIs
Publication statusPublished - 14 Jun 2018
Externally publishedYes

Fingerprint

Luminance
luminance
Symmetry
symmetry
stimuli
Lifetime
life (durability)
Modulation
modulation
Matched pairs
relocation
Relocation
Perception
Limiting
Vertical
Filter
intervals
filters
Interval
thresholds

Cite this

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title = "Spatiotemporal and luminance contrast properties of symmetry perception",
abstract = "Recent studies have shown that limiting the lifetime of pattern elements improves symmetry detection, potentially by increasing the number of element locations. Here, we investigate how spatial relocation, luminance contrast modulation and lifetime duration of elements affect symmetry perception in dynamic stimuli. Stimuli were dynamic dot-patterns containing varying amounts of symmetry about a vertical axis. Symmetrical matched-pairs were:(i) relocated to multiple successive, but random locations (ie, multiple locations condition);(ii) relocated between the same two locations (ie, two locations condition);(iii) not, relocated, but their luminance contrast was modulated at different temporal frequencies (ie, one location condition), and (iv) not relocated, but a single pattern was presented at full contrast (ie, static condition). In the dynamic conditions, we varied the elements’ lifetime duration and temporal frequency of contrast modulation. We measured symmetry detection thresholds using a two-interval forced choice procedure. Our results show improved performance for the multiple locations condition compared to two-location and static conditions, suggesting a cumulative process whereby weak symmetry information is integrated by spatiotemporal filters to increase overall symmetry signal strength. Performance also improved for the static, contrast modulated patterns, but this was explained by a reduction in perceived density. This suggests that different mechanisms mediate symmetry detection in dynamic stimuli and static contrast modulated patterns.",
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Spatiotemporal and luminance contrast properties of symmetry perception. / Sharman, Rebecca; Gheorghiu, Elena.

In: Symmetry, Vol. 10, No. 6, 220, 14.06.2018.

Research output: Contribution to journalSpecial issue

TY - JOUR

T1 - Spatiotemporal and luminance contrast properties of symmetry perception

AU - Sharman, Rebecca

AU - Gheorghiu, Elena

PY - 2018/6/14

Y1 - 2018/6/14

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AB - Recent studies have shown that limiting the lifetime of pattern elements improves symmetry detection, potentially by increasing the number of element locations. Here, we investigate how spatial relocation, luminance contrast modulation and lifetime duration of elements affect symmetry perception in dynamic stimuli. Stimuli were dynamic dot-patterns containing varying amounts of symmetry about a vertical axis. Symmetrical matched-pairs were:(i) relocated to multiple successive, but random locations (ie, multiple locations condition);(ii) relocated between the same two locations (ie, two locations condition);(iii) not, relocated, but their luminance contrast was modulated at different temporal frequencies (ie, one location condition), and (iv) not relocated, but a single pattern was presented at full contrast (ie, static condition). In the dynamic conditions, we varied the elements’ lifetime duration and temporal frequency of contrast modulation. We measured symmetry detection thresholds using a two-interval forced choice procedure. Our results show improved performance for the multiple locations condition compared to two-location and static conditions, suggesting a cumulative process whereby weak symmetry information is integrated by spatiotemporal filters to increase overall symmetry signal strength. Performance also improved for the static, contrast modulated patterns, but this was explained by a reduction in perceived density. This suggests that different mechanisms mediate symmetry detection in dynamic stimuli and static contrast modulated patterns.

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