Facial Age Aftereffects Provide Some Evidence for Local Repulsion (But None for Re-Normalisation). (April 2015)

• Record Type: Journal Article
• Authors: Storrs, Katherine R.
• Is Part Of: I-Perception. Volume 6:Number 2(2015)
• Page Start: 100
• Page End: 103
• Publication Date: 2015-04
• Subjects: adaptation -- face perception -- normalisation -- opponent coding -- visual aftereffects; Perception -- Periodicals; Visual perception -- Periodicals; Perception; Perception; Electronic journals; Periodical; Fulltext; Internet Resources; Periodicals; Periodicals; 153.7
• DOI: 10.1068/i0725jc
• Languages: English
• ISSNs: 2041-6695

Abstract

Face aftereffects can help adjudicate between theories of how facial attributes are encoded.O'Neil and colleagues (2014 ) compared age estimates for faces before and after adapting to young, middle-aged or old faces. They concluded that age aftereffects are best described as a simple re-normalisation—e.g. after adapting to old faces, all faces look younger than they did initially. Here I argue that this conclusion is not substantiated by the reported data. The authors fit only a linear regression model, which captures the predictions of re-normalisation, but not alternative hypotheses such as local repulsion away from the adapted age. A second concern is that the authors analysed absolute age estimates after adaptation, as a function of baseline estimates, so goodness-of-fit measures primarily reflect the physical ages of test faces, rather than the impact of adaptation. When data are re-expressed as aftereffects and fit with a nonlinear "locally repulsive" model, this model performs equal to or better than a linear model in all adaptation conditions. Data in O'Neil et al. do not provide strong evidence for either re-normalisation or local repulsion in facial age aftereffects, but are more consistent with local repulsion (and exemplar-based encoding of facial age), contrary to the original report.