Volume 7, Number 7, Article 9, Pages 1-12 doi:10.1167/7.7.9 http://journalofvision.org/7/7/9/ ISSN 1534-7362
How do attention and adaptation affect contrast sensitivity?
Franco Pestilli
Department of Psychology, New York University, New York, NY, USA
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Gerardo Viera
Department of Psychology, New York University, New York, NY, USA
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Marisa Carrasco
Department of Psychology and Center for Neural Science, New York University, New York, NY, USA
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Abstract

Attention and adaptation are both mechanisms that optimize visual performance. Attention optimizes performance by increasing contrast sensitivity for and neural response to attended stimuli while decreasing them for unattended stimuli; adaptation optimizes performance by increasing contrast sensitivity for and neural response to changing stimuli while decreasing them for unchanging stimuli. We investigated whether and how the adaptation state and the attentional effect on contrast sensitivity interact. We measured contrast sensitivity with an orientation-discrimination task, in two adaptation conditions—adapt to 0% or 100% contrast—in focused, distributed, and withdrawn attentional conditions. We used threshold and asymptotic performance to index the magnitude of the attentional effect—enhancement or impairment in contrast sensitivity—before and after adapting to high-contrast stimuli. The results show that attention and adaptation affect the contrast psychometric function in a similar but opposite way: Attention increases stimulus salience, whereas adaptation reduces stimulus salience. An interesting finding is that the adaptation state does not modulate the magnitude of the attentional effect. This suggests that attention affects the normalized signal once the effect of contrast adaptation has taken place and that these two mechanisms act separately to change contrast sensitivity. Attention can overcome adaptation to restore contrast sensitivity.

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History
Received December 28, 2006; published May 30, 2007
Citation
Pestilli, F., Viera, G., & Carrasco, M. (2007). How do attention and adaptation affect contrast sensitivity? Journal of Vision, 7(7):9, 1-12, http://journalofvision.org/7/7/9/, doi:10.1167/7.7.9.
Keywords
attention, adaptation, contrast sensitivity, orientation discrimination, contrast gain, response gain
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