Perception

Recent studies on the development of face processing argue for a late, quantitative, domain-specific development of face processing, and face memory in particular. Most previous findings were based on separately tracking the developmental course of face perception skills, comparing performance across different age groups. Here, we adopted a different approach studying the mechanisms underlying the development of face processing by focusing on how different face skills are interrelated over the years (age 6 to adulthood). Specifically, we examined correlations within and between different categories of tasks: face domain-specific skills involving face recognition based on long-term representations (famous face), and short-term memory retention (Cambridge Face Memory Test), perceptual face-specific marker (inversion effect), global effects in scene perception (global–local task), and the perception of facial expressions. Factor analysis revealed that face identity skills have a similar pattern of interrelations throughout development, identifying two factors: a face domain-specific factor comprising adultlike markers of face processing and a general factor incorporating related, but nonspecific perceptual skills. Domain-specific age-related changes in face recognition entailing short- and long-term retention of face representations were observed, along with mature perceptual face-specific markers and more general perceptual effects predicting face perception skills already at age 6. The results suggest that the domain-specific changes in face processing are unlikely to result from developmental changes in perceptual skills driving face recognition. Instead, development may either involve improvement in the ability to retain face representations in memory or changes in the interactions between the perceptual representations of faces and their representations in long-term memory.

Several facial expression image sets have been developed. Nevertheless, there is a lack of facial expression sets comprising adolescents’ images depicting all basic emotions. This study aimed to fill this gap through the development of an image database of youth facial expressions, containing pictures of six basic emotions plus neutral. Posed and spontaneous expressions were collected from 31 youths, 12 to 20 years old; 2,279 frames were obtained, and an initial screening was conducted through the exclusion of similar frames, low intensity images, and ambiguous or blended expressions; 256 frames met criteria and were rechecked by two expert judges. Images were retained if they depicted all the prototypical features of the designated expression. A final selection was conducted to assure an image set that covered all age ranges, both sexes and an even number of images by expression, resulting in 42 frames (21 male, six of each emotion). Expert judges, independent adults, independent teenagers, and a software validation were used to assure database validity. Agreement across raters was high, and no differences were observed for posed and spontaneous images. The data set developed in this study can be a valid tool in studies of facial expressions, in particular, with adolescents’ samples.

First impressions from faces emerge quickly and shape subsequent behaviour. Given that different pictures of the same face evoke different impressions, we asked whether presentation order affects the overall impression of the person. In three experiments, we presented naturally varying photos of a person’s face in ascending (low-to-high) or descending (high-to-low) order of attractiveness. We found that attractiveness ratings for a subsequent test item were higher for the descending condition than for the ascending condition (Experiment 1), consistent with anchoring effects. In Experiment 2, we ruled out contrast between the final item and the test item as the cause of the effect by demonstrating anchoring within the sequence itself. In Experiment 3, we found that order of image presentation also affected dating decisions. Our findings demonstrate that first impressions from faces depend not only on visual information but also on the order in which that information is received. We suggest that models of impression formation and learning of individual faces could be improved by considering temporal order of encounters.

Body odors (BOs) can convey social information. In particular, their effects are maximal when their presence is paired with meaningful social contexts. Static faces have been widely used as social stimuli. However, they miss a key feature of our phenomenological experience, characterized by multisensory dynamic stimulations. Here, we investigate how BO sampled from individuals experiencing a transitory anxiety state, (a) induce a stress response and (b) bias the recognition of dynamic facial expressions, compared with BO of relaxed individuals. Participants (n=46) categorized the emotion of a face, morphing from a neutral expression to either an angry or happy expression, during exposure to either BO condition. In addition, their cardiac activity was measured. Exposure to anxiety BO increased the accuracy of dynamic facial recognition and reduced cardiac parasympathetic activity. These results suggest that in social situations that simulate part of the multisensory and dynamic features of real-life social contexts, anxiety BOs will induce a stress response in recipients, modulating both arousal and cognitive-emotional skills but facilitating emotional facial processing.

When we hold thin metallic bars between the palms of our hands and rub the palms against each other, the feeling of touching smooth velvet occurs. Previous studies have shown that tactile motion and pressure on the palms are important for this velvet hand illusion. Interestingly, when we experience this illusion, we cannot feel the texture of our palms as we usually do. In the present study, we investigated the possibility that tactile masking contributes to the occurrence of the velvet hand illusion. We measured vibrotactile detection performance on the palms of the hands during the occurrence of the velvet hand illusion. The detection performance was worse when the illusion occurred than when it did not. Moreover, the degradation of the detection performance correlated positively with the subjective magnitude of the illusion. We also examined whether additional surface texture could affect the occurrence of the illusion and found that the illusion became weaker as the roughness of the surface increased. These findings suggest that tactile motion and pressure information delivered by the bars of smooth surface mask tactile sensations on the palms of the hands, resulting in an illusory smooth, frictionless feeling on the palms.

Recent research has shown that adults and children with autism spectrum disorders have a more conservative decision criterion in perceptual decision making compared to neurotypical individuals, meaning that autistic participants prioritise accuracy over speed of a decision. Here, we test whether autistic traits in the neurotypical population correlate with increased response conservativeness. We employed three different tasks; for two tasks we recruited participants from China (N = 39) and for one task from the United Kingdom (N = 37). Our results show that autistic traits in the neurotypical population do not predict variation in response criterion. We also failed to replicate previous work showing a relationship between autistic traits and sensitivity to coherent motion and static orientation. Following the argument proposed by Gregory and Plaisted-Grant, we discuss why perceptual differences between autistic and neurotypical participants do not necessarily predict perceptual differences between neurotypical participants with high and low autistic traits.

We examined the effect of visual attention on binocular fusion limits by using Posner’s spatial cueing paradigm that entails cued shifts of attentional focus. Results showed that attention decreases the fusion limit. Observers perceived diplopia of a binocular line within +/−26.5 arcmin disparity (+/− correspond to uncrossed and crossed, respectively) more frequently when it was oriented to the line than when cued attention was directed elsewhere. We discuss the results in terms of attention increasing spatial resolution and contrast sensitivity.

Perception of possibilities for behavior reflects the task-specific fit between action capabilities and environmental properties. We investigated whether this is so for a behavior that requires spontaneously and temporarily coordinating anatomical components and inert objects into a person-plus-object action system—stepping over an expanse with crutches. We found that perception of this affordance (a) scaled to an anthropometric property of primary relevance to performing this behavior (leg length), (b) reflected the ability to perform this behavior, and that (c) variability in perception decreased with practice perceiving this affordance. The results are consistent with the proposal that perceiving affordances for a given behavior requires assembling a task-specific perceptual instrument.