Regine Armann

Gaze behavior in face comparison: The roles of sex, task, and symmetry

Knowing where people look on a face provides an objective insight into the information entering the visual system and into cognitive processes involved in face perception. In the present study, we recorded eye movements of human participants while they compared two faces presented simultaneously. Observers’ viewing behavior and performance was examined in two tasks of parametrically varying difficulty, using two types of face stimuli (sex morphs and identity morphs). The frequency, duration, and temporal sequence of fixations on previously defined areas of interest in the faces were analyzed. As was expected, viewing behavior and performance varied with difficulty. Interestingly, observers compared predominantly the inner halves of the face stimuli—a result inconsistent with the general left-hemiface bias reported for single faces. Furthermore, fixation patterns and performance differed between tasks, independently of stimulus type. Moreover, we found differences in male and female participants’ viewing behaviors, but only when the sex of the face stimuli was task relevant.

A familiarity disadvantage for remembering specific images of faces.

Familiar faces are remembered better than unfamiliar faces. Furthermore, it is much easier to match images of familiar than unfamiliar faces. These findings could be accounted for by quantitative differences in the ease with which faces are encoded. However, it has been argued that there are also some qualitative differences in familiar and unfamiliar face processing. Unfamiliar faces are held to rely on superficial, pictorial representations, whereas familiar faces invoke more abstract representations. Here we present 2 studies that show, for 1 task, an advantage for unfamiliar faces. In recognition memory, viewers are better able to reject a new picture, if it depicts an unfamiliar face. This rare advantage for unfamiliar faces supports the notion that familiarity brings about some representational changes, and further emphasizes the idea that theoretical accounts of face processing should incorporate familiarity. (PsycINFO Database Record

The contribution of foveal and peripheral visual information to ensemble representation of face race

The brain can only attend to a fraction of all the information that is entering the visual system at any given moment. One way of overcoming the so-called bottleneck of selective attention (e.g., J. M. Wolfe, Võ, Evans, & Greene, 2011) is to make use of redundant visual information and extract summarized statistical information of the whole visual scene. Such ensemble representation occurs for low-level features of textures or simple objects, but it has also been reported for complex high-level properties. While the visual system has, for example, been shown to compute summary representations of facial expression, gender, or identity, it is less clear whether perceptual input from all parts of the visual field contributes equally to the ensemble percept. Here we extend the line of ensemble-representation research into the realm of race and look at the possibility that ensemble perception relies on weighting visual information differently depending on its origin from either the fovea or the visual periphery. We find that observers can judge the mean race of a set of faces, similar to judgments of mean emotion from faces and ensemble representations in low-level domains of visual processing. We also find that while peripheral faces seem to be taken into account for the ensemble percept, far more weight is given to stimuli presented foveally than peripherally. Whether this precision weighting of information stems from differences in the accuracy with which the visual system processes information across the visual field or from statistical inferences about the world needs to be determined by further research.

The Other-Race Effect Revisited: No Effect for Faces Varying in Race Only

The other-race effect refers to the observation that we perform better in tasks involving faces of our own race compared to faces of a race we are not familiar with. This is especially interesting as from a biological perspective, the category “race” does in fact not exist (Cosmides L, Tooby J, Krurzban R, Trends Cogn Sci 7(4):173–179, 2003); visually, however, we do group the people around us into such categories. Usually, the other-race effect is investigated in memory tasks where observers have to learn and subsequently recognize faces of individuals of different races (Meissner CA, Brigham JC, Psychol Public Policy Law 7(1):3–35, 2001) but it has also been demonstrated in perceptual tasks where observers compare one face to another on a screen (Walker PM, Tanaka J, Perception 32(9):1117–1125, 2003). In all tasks (and primarily for technical reasons) the test faces differ in race and identity. To broaden our general understanding of the effect that the race of a face has on the observer, in the present study, we investigated whether an other-race effect is also observed when participants are confronted with faces that differ only in ethnicity but not in identity. To that end, using Asian and Caucasian faces and a morph algorithm (Blanz V, Vetter T, A morphable model for the synthesis of 3D faces. In: Proceedings of the 26th annual conference on Computer graphics and interactive techniques – SIGGRAPH’99, pp 187–194, 1999), we manipulated each original Asian or Caucasian face to generate face “race morphs” that shared the same identity but whose race appearance was manipulated stepwise toward the other ethnicity. We presented each Asian or Caucasian face pair (original face and a race morph) to Asian (South Korea) and Caucasian (Germany) participants who had to judge which face in each pair looked “more Asian” or “more Caucasian”. In both groups, participants did not perform better for same-race pairs than for other-race pairs. These results point to the importance of identity information for the occurrence of an other-race effect.