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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Modulation of perceived contrast in the brightness comparison of asynchronous stimuli

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Author(s):
Claessens, Peter M. E. [1, 2, 3] ; Pereira, Lucas Oliveira [2, 3] ; Baldo, Marcus Vinicius C. [1]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Inst Ciencias Biomed, Dept Fisiol & Biofis, Lab Fisiol Sensorial Roberto Vieira, BR-05508000 Sao Paulo - Brazil
[2] UFABC, Nucleo Cognicao & Sistemas Complexos, BR-09606070 Sao Bernardo Do Campo, SP - Brazil
[3] UFABC, Ctr Matemat Comp & Cognicao, BR-09606070 Sao Bernardo Do Campo, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: ATTENTION PERCEPTION & PSYCHOPHYSICS; v. 77, n. 1, p. 234-248, JAN 2015.
Web of Science Citations: 0
Abstract

Comparative judgment is a crucial task in ecological settings, as well as in many experimental studies about basic aspects of perceptual processes. It has long been known that sequential comparison is prone to order effects. This phenomenon has received little attention and has often been discounted as a type of response bias. In the present study, we investigated brightness discrimination of two brief (100 ms) spatially disjoint luminance stimuli. In the first and second experiments, stimuli were presented against a dark background with a stimulus onset asynchrony (SOA) from 0 to 200 ms, in a paradigm controlling for response bias. In the third experiment, stimuli were presented against a bright background. We demonstrate that the time interval between stimuli modulates and even inverts their perceived brightness difference, enhancing the second stimulus relative to the first. When the background is brighter than the target stimuli, the sign of the effect is inverted, suggesting that the underlying mechanism operates on contrast rather than brightness. The magnitude of this effect is shown to depend on SOA and average luminance level of the target stimuli. Hypotheses in terms of neural and attentional dynamics are proposed. (AU)

FAPESP's process: 06/50189-9 - Spatiotemporal dynamics of attention: formalization and flash-lag phenomena
Grantee:Peter Maurice Erna Claessens
Support Opportunities: Scholarships in Brazil - Post-Doctoral