Perception

Compelling evidence that faces are perceived holistically or configurally comes from the composite face illusion: Identical top halves of a face are perceived as being different if they are aligned with different bottom halves. The visual illusion disappears when the top and bottom face halves are spatially misaligned. Whether this is because the two halves no longer form a whole face (ie they form two segmented parts), or because of an increase in interfeatures distance in the misaligned condition (eg eyes-mouth distance) remains unclear. Here, thirty-four participants performed a delayed matching composite task in which the amount of spatial misalignment between face halves varied parametrically (from 8.33% of face width to 100%). The difference in performance between aligned and misaligned faces (ie the composite face effect) was already of full magnitude at the smallest level of misalignment. These results imply that a small spatial misalignment is sufficient to measure the composite face effect. From a theoretical standpoint, they indicate that it is the breaking of a whole configuration rather than the increase in relative distance between the face parts that explains the presence or absence of the composite face effect, clarifying an outstanding issue concerning the nature of holistic face perception.

As faces often appear under very different viewing conditions (eg brightness, viewing angle, or viewing distance), invariant facial information recognition is a key to our social interactions. Although we would clearly benefit from differentiating different facial expressions (eg angry vs happy) at a distance, there is surprisingly little research examining how expression categorization and associated gaze allocation are affected by viewing distance within the range of typical social space. In this study I systematically varied the size of faces displaying six basic facial expressions of emotion with varying intensities to mimic viewing distances ranging from arms length to 5 m, and employed a self-paced expression categorization task to measure participants' categorization performance and associated gaze patterns. Irrespective of the displayed expression and its intensity, the participants showed indistinguishable categorization accuracy and reaction time across the tested face sizes. Reducing face size decreased the number of fixations directed at the faces but increased individual fixation durations, and shifted gaze distribution from scanning all key internal facial features to fixating at mainly the central face region. The results suggest size-invariant facial expression categorization behaviour within social interaction distance which could be linked to a holistic gaze strategy for extracting expressive facial cues.

The present study compared the performance of a group of sixteen kung fu athletes with that of a control group of fourteen nonathletes on a speeded visuospatial task and a hand-tapping motor task. In the visuospatial task the results showed that athletes were faster than the control participants when stimuli were presented at the periphery of the visual field at a middle and high presentation speed with short interstimulus intervals. Athletes were also significantly faster than nonathlete participants when performing motor actions such as hand-tapping with their dominant hand but groups did not differ with the nondominant hand. These results support the view that athletes perform some speeded visuospatial and motor tasks faster than nonathletes under certain conditions. The findings suggest that, after several years of practice, kung fu athletes develop certain skills that allow them to perform motor speed maneuvers under time pressure conditions.

We demonstrate a perceptual effect whereby contours not physically present in a visual scene can yield striking illusory motion. The not physically present contours are paths of invariant contrast polarity (CP). For example, when a square checkerboard composed of dark and light square checks with small black and white discs covering the vertices is put in lateral motion, there is the striking perception of vertical expansion/contraction. Such a checkerboard has (not physically present) diagonal paths of CP presentation with vertical components. However, when a square checkerboard made up of square black and very light checks with gray discs of luminance intermediate to the checks is put in lateral motion, no expansion/contraction is seen. For this checkerboard the vertical components of paths of CP preservation cancel each other out, predicting the lack of perception of vertical expansion/contraction. We also discuss how not physically present contours can explain previously described effects and suggest new effects to be explored.

Four-year-old children often have difficulty visually recognizing objects that were previously experienced only haptically. This experiment attempts to improve their performance in these haptic-to-visual transfer tasks. Sixty-two 4-year-old children participated in priming trials in which they explored eight unfamiliar objects visually, haptically, or visually and haptically together. Subsequently, all children participated in the same haptic-to-visual cross-modal transfer task. In this task, children haptically explored the objects that were presented in the priming phase and then visually identified a match from among three test objects, each matching the object on only one dimension (shape, texture, or color). Children in all priming conditions predominantly made shape-based matches; however, the most shape-based matches were made in the Visual and Haptic condition. All kinds of priming provided the necessary memory traces upon which subsequent haptic exploration could build a strong enough representation to enable subsequent visual recognition. Haptic exploration patterns during the cross-modal transfer task are discussed and the detailed analyses provide a unique contribution to our understanding of the development of haptic exploratory procedures.

The programs iMAP and iMAP2, developed by Caldara and Miellet (2011 Behavior Research Methods 43 846–878), have attempted to implement a general approach to the analysis of eye-movement data, providing not only ‘heat maps’ of areas of greater and lesser activity but also, and potentially of great practical importance, significance tests which take into account spatial autocorrelation in fixation locations. The tests in particular allow different groups to be compared, as in one of Caldara and Miellet's example datasets where fixation patterns of Western Caucasian and East Asian participants are said to be significantly different. The present paper argues that the significance tests, as implemented, used an inappropriate algorithm and therefore gave erroneous results. In particular, if participants are randomly allocated to two groups, which is a conventional randomization test, then in every case the program claimed to find ‘significant differences‘, which cannot be correct. A simple, modified statistical technique, based around a simple two-group t-test, with error functions and spatial autocorrelation taken into account, finds no differences between the example groups of participants. That conclusion is reinforced by analyzing simulated data with or without true differences, when iMAP/iMAP2 always finds significant differences, irrespective of sample size, whereas the modified method finds significant differences for only the largest sample sizes. Previous research using iMAP/iMAP2 may have come to erroneous conclusions about differences in fixation patterns between groups.

We are often not explicitly aware of the location of our spatial attention, despite its influence on our perception and cognition. During a picture memory task, we asked whether people could later recognise their eye fixations in a two-alternative test. In three separate experiments, participants performed above chance when discriminating their own fixation patterns from random locations or locations fixated in a different image. Recognition was much poorer when the task was to spot your own versus someone else's fixations on the same stimulus, but performance remained better than chance. That we are sensitive to our own scan patterns has implications for perception, memory, and meta-cognition.

Social categorization is a rapid and automatic process, and people rely on various facial cues to accurately categorize each other into social groups. Recently, studies have demonstrated that people integrate different cues to arrive at accurate impressions of others' sexual orientations. The amount of perceptual information available to perceivers could affect these categorizations, however. Here, we found that, as visual information decreased from full faces to internal facial features to just pairs of eyes, so did the accuracy of judging women's sexual orientation. Yet and still, accuracy remained significantly greater than chance across all conditions. More important, however, participants' response bias varied significantly depending on the facial feature judged. Perceivers were significantly more likely to consider that a target may be lesbian as they viewed less of the faces. Thus, although facial features may be continuously integrated in person construal, they can differentially affect how people see each other.

A mathematical measure of pattern complexity based on subsymmetries possessed by the pattern, previously shown to correlate highly with empirically derived measures of cognitive complexity in the visual domain, is found to also correlate significantly with empirically derived complexity measures of perception and production of auditory temporal and musical rhythmic patterns. Not only does the subsymmetry measure correlate highly with the difficulty of reproducing the rhythms by tapping after listening to them, but also the empirical measures exhibit similar behavior, for both the visual and auditory patterns, as a function of the relative number of subsymmetries present in the patterns.