Race-contingent face aftereffects: A result of perceived racial typicality, not categorization

O. Scott Gwinn, Kevin R. Brooks

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Opposing aftereffects can be simultaneously induced by adapting to faces of different races distorted in opposite directions, allowing researchers to infer that faces are encoded against race-specific prototypes. This effect also suggests the existence of dissociable pools of neurons sensitive to race, each of which has been differently adapted to cause an opposite aftereffect. More recent studies have suggested that changes in the strength of race-contingent aftereffects reveal evidence of categorical perception, as they are larger when the adapting faces straddle the racial category boundary. We examined whether changes in these effects more closely correspond to a dichotomous categorical judgment, reflecting highly race-selective neural mechanisms, or more continuous perceptions of racial typicality, reflecting visual channels that are more broadly tuned. In Experiment 1, faces with a range of "morph levels"(i.e., relative contributions of Asian/ Caucasian faces) were either rated on a continuous scale for Asian/Caucasian typicality, or simply categorized as Asian/Caucasian. As expected, typicality ratings showed a shallow slope (observers were sensitive to morph level over a broad range), while dichotomous racial categorization showed a steep slope (a rapid switch from categorization as Asian-Caucasian). In Experiment 2, race-contingent adaptation was assessed using test faces with various morph levels. Aftereffect size showed a shallow slope, closely resembling the racial typicality ratings, but showing a significant difference to the categorization data. This suggests that although the visual channels processing these faces do show some selectivity to race, they are sensitive to perceptions of racial typicality, showing a gradual transition of activity across a broad range of faces along the racial continuum.

LanguageEnglish
Article number13
Pages1-11
Number of pages11
JournalJournal of Vision
Volume13
Issue number10
DOIs
Publication statusPublished - 2013

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Keywords

  • Adaptation
  • Aftereffects
  • Face-space
  • Faces
  • Neural mechanisms
  • Race

Cite this

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Race-contingent face aftereffects : A result of perceived racial typicality, not categorization. / Gwinn, O. Scott; Brooks, Kevin R.

In: Journal of Vision, Vol. 13, No. 10, 13, 2013, p. 1-11.

Research output: Contribution to journalArticleResearchpeer-review

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