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We used a preferential looking technique to investigate the effect of support ratio (a ratio of the physically specified contours to the total edge length) on the perception of Kanizsa illusory contours in infants aged 3–8 months. Previous work has shown that for adult observers the illusory-contour strength increases proportionally with the support ratio. When the support ratio was relatively high (66%), infants preferred illusory contours to non-illusory figures by 3–4 months of age (experiment 1). In contrast, only infants 7–8 months old showed this preference for illusory contours when the support ratio was reduced to 37% (experiment 3). Further, infants showed no preference for an outline version of the illusory-contour figure, which produced no illusory contours (experiment 2). This result confirms that the infants' preference reflects their perception of illusory contours. Our results show that (i) illusory-contour perception emerges at around 3–4 months of age, but (ii) that this ability is very limited until around 7–8 months of age.

This study examined infants' visual perception of three-dimensional common objects. It has been reported that human adults perceive object images in a view-dependent manner: three-quarter views are often preferred to other views, and the sensitivity to object orientation is lower for three-quarter views than for other views. We tested whether such characteristics were observed in 6- to 8-month-old infants by measuring their preferential looking behavior. In Experiment 1 we examined 190- to 240-day-olds' sensitivity to orientation change and in Experiment 2 we examined these infants' preferential looking for the three-quarter view. The 240-day-old infants showed a pattern of results similar to adults for some objects, while the 190-day-old infants did not. The 240-day-old infants' perception of object view is (partly) similar to that of adults. These results suggest that human visual perception of three-dimensional objects develops at 6 to 8 months of age.

The special issue of Japanese PsychologicalResearch is focusing on face perception andrecognition in humans and primates. Theauthors were the main members of the officialresearch project, a Grant-in-Aid for ScientificResearch on Innovative Areas (Shin GakujutuRyoiki Kenkyu),“Face perception and recogni-tion: Multidisciplinary approaching to under-standingfaceprocessingmechanisms”,support-edbytheMinistryofEducation,Culture,Sports,Science and Technology (MEXT), Japan. Thisresearch project started in 2008 and finished atthe end of March, 2013. This project involvedabout fifty researchers whose research fieldswere multidisciplinary. Therefore, researcherswere classified in the following six groups:A1 group: Hemodynamic study, mainly func-tional magnetic resonance imaging (fMRI) andnear infra-red spectroscopy (NIRS)A2 group: Electrophysiological study, mainlyelectroencephalography (EEG) and magneto-encephalography (MEG)A3 group: Clinical study, mainly focusing onautismA4 group: Psychological studyA5 group: Behavioral and electrophysiologicalstudy using monkeysA6 group: Technological and physical groupThe MEXT, Japan, strongly supported thisproject,andthetotalbudgetwasapproximately10 000 000 USD. In fact, I think that this is thefirst and only research project focusing on faceperception and recognition employing multi-disciplinary methods in the world.Based on the excellent results obtained inthe five years, the International Symposium,“Face perception and recognition”, took placein Okazaki, Japan from October 30 to Novem-ber 3, 2012. Surprisingly, approximately 160researchers including over forty researchersfrom abroad participated in this symposium.More than 100 excellent lectures and posterpresentations were delivered, and in-depthdiscussions took place. From the many ex-cellent presentations, mainly psychological,neuroimaging, and physiological studies arepublished in this special issue.By reading these excellent articles,I am surethat the hottest and most advanced studies inthis particular field will be understood. Finally,I hope that young researchers, particularlywho have not studied face perception and rec-ognition, will be impressed by these articles,become interested in this field, and study it inthe future.RYUSUKE KAKIGI*

Japanese male and female undergraduate students judged the gender of a variety of facial images. These images were combinations of the following facial parts: eyebrows, eyes, nose, mouth, and the face outline (cheek and chin). These parts were extracted from averaged facial images of Japanese males and females aged 18 and 19 years by means of the Facial Image Processing System. The results suggested that, in identifying gender, subjects performed identification on the basis of the eyebrows and the face outline, and both males and females were more likely to identify the faces as those of their own gender. The results are discussed in relation to previous studies, with particular attention paid to the matter of race differences.

We examined the role of motion information on infants' recognition of unfamiliar faces. Previous studies suggested that motion information promotes infants' perception (Kellman & Spelke, 1983; Otsuka & Yamaguchi, 2003), and therefore we theorized that motion information should facilitate infants' face recognition. In the present study, we compared infants' recognition memory for unfamiliar faces learned in a moving or a static condition. Infants aged 3- to 5- months (N = 24) were first familiarized with a smiling woman face either in the moving or static condition. After familiarization, infants were tested using a pair of novel and familiar female faces. Both novel and familiar faces in the test phase had static, neutral expressions. Hair was excluded so that only the internal features were visible. We found that the infants in the moving condition showed a significant preference for novel faces, but that the infants in the static condition showed no preference for either of the faces. The present results suggest that learning from moving condition promotes infants' recognition of unfamiliar faces.

Children with attention-deficit/hyperactivity disorder (ADHD) have difficulty recognizing facial expressions. They identify angry expressions less accurately than typically developing (TD) children, yet little is known about their atypical neural basis for the recognition of facial expressions. Here, we used near-infrared spectroscopy (NIRS) to examine the distinctive cerebral hemodynamics of ADHD and TD children while they viewed happy and angry expressions. We measured the hemodynamic responses of 13 ADHD boys and 13 TD boys to happy and angry expressions at their bilateral temporal areas, which are sensitive to face processing. The ADHD children showed an increased concentration of oxy-Hb for happy faces but not for angry faces, while TD children showed increased oxy-Hb for both faces. Moreover, the individual peak latency of hemodynamic response in the right temporal area showed significantly greater variance in the ADHD group than in the TD group. Such atypical brain activity observed in ADHD boys may relate to their preserved ability to recognize a happy expression and their difficulty recognizing an angry expression. We firstly demonstrated that NIRS can be used to detect atypical hemodynamic response to facial expressions in ADHD children.

We investigated the anisotropic responses between the detection of motion toward and motion away from the observers with expanding/contracting shaded circles. Our experiments followed visual search paradigm with two exceptions: (1) the stimulus presentation time was fixed for 300 ms and (2) the mean error rates were adopted as a dependent variable. In Experiment 1, targets and distractors were defined by expanding (or contracting) convex/concave circles. Results of Experiment 1 suggested that the human visual system is more sensitive to expanding convex circles (which create the impression of approaching objects) than others. In Experiment 2, the targets and distractors were defined by expanding (or contracting) step gradient (top-lighting/bottom-lighting) circles. The results of Experiment 2 suggest that the anisotropy for the perception of motion-in-depth should not be caused by change of luminance polarity but by change of shading cue.