Psychophysical evidence for a non-linear representation of facial identity

Dakin, Steven C and Omigie, Diana. 2009. Psychophysical evidence for a non-linear representation of facial identity. Vision Research, 49(18), pp. 2285-2296. ISSN 0042-6989 [Article]

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Abstract or Description

It has been proposed that faces are represented in the visual brain as points within a multi-dimensional “face space”, with the average at its origin. We adapted a psychophysical procedure that measures non-linearities in contrast transduction (by measuring discrimination around different reference/pedestal levels of contrast) to examine the encoding of facial-identity within such a notional space. Specifically we had subjects perform identity discrimination at various pedestal levels of identity (varying from average/0% to caricature/125% identity) to derive “identity dipper functions”. Results indicate that subjects are generally best at spotting identity change in neither average nor full-identity faces, but rather in faces containing an intermediate level of identity (which varies from face-to-face). The overall pattern of results is consistent with the neural encoding of faces involving a single modest non-linear transformation of identity that is consistent across faces and subjects, but that it scaled according to the distinctiveness of the face.

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Face perception, Discrimination, Identity, Dipper function, Average face

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17 June 2009Published

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Date Deposited:

28 Jun 2018 15:17

Last Modified:

29 Apr 2020 16:46

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Yes, this version has been peer-reviewed.


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