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Chris Winkler

Publications and source records attributed to Chris Winkler.

3 recordsLinked to original sources

Attractiveness of own-race, other-race, and mixed-race faces.

Averaged face composites, which represent the central tendency of a familiar population of faces, are attractive. If this prototypicality contributes to their appeal, then averaged composites should be more attractive when their component faces come from a familiar, own-race population than when they come from a less familiar, other-race population. We compared the attractiveness of own-race composites, other-race composites, and mixed-race composites (where the component faces were from both races). In experiment 1, Caucasian participants rated own-race composites as more attractive than other-race composites, but only for male faces. However, mixed-race (Caucasian/Japanese) composites were significantly more attractive than own-race composites, particularly for the opposite sex. In experiment 2, Caucasian and Japanese participants living in Australia and Japan, respectively, selected the most attractive face from a continuum with exaggerated Caucasian characteristics at one end and exaggerated Japanese characteristics at the other, with intervening images including a Caucasian averaged composite, a mixed-race averaged composite, and a Japanese averaged composite. The most attractive face was, again, a mixed-race composite, for both Caucasian and Japanese participants. In experiment 3, Caucasian participants rated individual Eurasian faces as significantly more attractive than either Caucasian or Asian faces. Similar results were obtained with composites. Eurasian faces and composites were also rated as healthier than Caucasian or Asian faces and composites, respectively. These results suggest that signs of health may be more important than prototypicality in making average faces attractive.

Asian People↗

Orientation-contingent face aftereffects and implications for face-coding mechanisms.

Humans have an impressive ability to discriminate between faces despite their similarity as visual patterns. This expertise relies on configural coding of spatial relations between face features and/or holistic coding of overall facial structure. These expert face-coding mechanisms appear to be engaged most effectively by upright faces, with inverted faces engaging primarily feature-coding mechanisms. We show that opposite figural aftereffects can be induced simultaneously for upright and inverted faces, demonstrating that distinct neural populations code upright and inverted faces. This result also suggests that expert (upright) face-coding mechanisms can be selectively adapted. These aftereffects occur for judgments of face normality and face gender and are robust to changes in face size, ruling out adaptation of low-level, retinotopically organized coding mechanisms. Our results suggest a resolution of a paradox in the face recognition literature. Neuroimaging studies have found surprisingly little orientation selectivity in the fusiform face area (FFA) despite evidence that this region plays a role in expert face coding and that expert face-coding mechanisms are selectively engaged by upright faces. Our results, demonstrating orientation-contingent adaptation of face-coding mechanisms, suggest that the FFA's apparent lack of orientation selectivity may be an artifact of averaging across distinct populations within the FFA that respond to upright and inverted faces.

Adult↗

The selective values of alleles in a molecular network model are context dependent.

Classical quantitative genetics has applied linear modeling to the problem of mapping genotypic to phenotypic variation. Much of this theory was developed prior to the availability of molecular biology. The current understanding of the mechanisms of gene expression indicates the importance of nonlinear effects resulting from gene interactions. We provide a bridge between genetics and gene network theories by relating key concepts from quantitative genetics to the parameters, variables, and performance functions of genetic networks. We illustrate this methodology by simulating the genetic switch controlling galactose metabolism in yeast and its response to selection for a population of individuals. Results indicate that genes have heterogeneous contributions to phenotypes and that additive and nonadditive effects are context dependent. Early cycles of selection suggest strong additive effects attributed to some genes. Later cycles suggest the presence of strong context-dependent nonadditive effects that are conditional on the outcomes of earlier selection cycles. A single favorable allele cannot be consistently identified for most loci. These results highlight the complications that can arise with the presence of nonlinear effects associated with genes acting in networks when selection is conducted on a population of individuals segregating for the genes contributing to the network.

Alleles↗