Perception

Face perception is critical to social interaction, yet people consistently recognize own-race faces more accurately than other-race faces, a robust phenomenon known as the other-race effect (ORE). Although facial variability affects recognition, how naturalistic variations modulate the other-race effect remains unclear. To address this, we compared recognition performance on two standardized memory tests that differ in facial variability: the Cambridge Face Memory Test (CFMT), which includes controlled variability (systematic changes in lighting, and pose), and the Variability Face Memory Test (VFMT), which incorporates high naturalistic variability (e.g., lighting, poses, expression, viewing distance, hairstyle, and appearance). Sixty East Asian young adults (18-25 years) with limited cross-race contact completed both tests using own-race (Asian) and other-race (White) face sets. Both tests assess between-person discrimination and within-person recognition of identities across variable images. Results revealed a significantly stronger ORE under high variability (VFMT), where recognition of other-race faces was substantially impaired relative to own-race faces. In contrast, the ORE was minimal under low variability (CFMT). These findings suggest that naturalistic facial variation disproportionately disrupts other-race face recognition, particularly in within-person recognition tasks. This supports theoretical accounts of compressed face-space representations for other-race faces, in which limited experience reduces tolerance for natural variability. Overall, these results highlight that real-world facial variability amplifies the ORE, emphasizing the role of perceptual experience with facial variability in cross-racial face recognition under natural conditions.

Artificial intelligence (AI) is changing society in major ways. AI can create content that entertains, but it can also mislead people. One part of this change is the ability to produce human-like AI content, including voices and faces. In psychology, AI-generated faces have started to be used to study face perception, thanks to their flexibility and convenience. This choice appears to be supported by recent evidence indicating that AI-generated faces are indistinguishable from human faces. However, other findings suggest that AI- or computer-generated faces may be evaluated differently than real faces, with AI-generated faces even leading to hyperrealism. To address this, we conducted a study to investigate whether human and AI-generated faces are recognized similarly in a memory task, and whether their recognition is related to our evaluation of these faces. Results show that recognition accuracy was significantly higher for AI faces than for real faces. Critically, classification (i.e., the ability to correctly classify a face as human or AI-generated) accuracy was significantly better than chance level for both real and AI-generated faces, with no difference between the two. These results suggest that humans can correctly discriminate AI-generated and human faces, and that AI-faces might be recognized better than human ones, suggesting that AI-generated faces might engage human perceptual and memory systems differently from real faces. However, recognition and classification accuracy were not significantly correlated, suggesting that participants might be partially unaware of their increased performance with AI-generated faces.

This study investigates how the background color of the Lindau Crucifixion, a fifteenth-century panel painting by the Master of the Lamentation of Christ in Lindau, affects visual perception. Originally gilded, the painting was later overpainted with a blue paint, raising questions in conservation about whether to preserve the intervention or restore the gold. To assess potential perceptual consequences, we used digital reconstructions of the painting in eye-tracking and gist perception experiments. In the eye-tracking task, participants viewed each version for 6 s among similar medieval paintings. Faces were consistently gazed at, while angels attracted less gaze. However, a slightly reduced likelihood of fixating angels was found for the blue background. In the gist perception task, participants described similar elements across both versions, reporting the central figures regardless of background color. These findings suggest limited perceptual differences under brief viewing, highlighting the potential of perceptual experiments to inform art conservation decisions.

Tracking eye movements as individuals view emotional facial expressions can offer insight into the mechanisms underlying emotion recognition. Few studies compare eye gaze patterns across static and dynamic expressions, and even fewer use ecologically valid audio-visual stimuli. Research is also limited on individual differences in emotion processing and how these relate to recognition performance. In this study, we address this gap by examining the eye movement patterns of adult participants (n = 73) during emotion recognition of individuals in static photos, dynamic videos, and audio-visual videos. Using pre-defined region-of-interest analyses and Hidden Markov Models, we explored whether individuals focused on different areas of the face across conditions, whether individual eye movement patterns were consistent across conditions, and whether certain patterns were associated with better performance. The findings showed that a) individuals focused more on the eye region when recognising static expressions compared to moving expressions; b) individuals’ eye movement patterns during emotion recognition were highly consistent, albeit most likely to change between static and moving conditions; c) there was not one particular pattern associated with improved emotion recognition accuracy. Ultimately, we report that the emotion recognition of static emotional expressions differs from moving expressions, suggesting recognition is influenced by movement, highlighting important considerations for future research to include more realistic stimuli to be better able to generalise to real-world social interactions.

To what degree is it possible to recognize a person's ethnicity just from their face? What information do you need to do so? Here, we present the first investigation addressing these questions, and in particular the role of internal and external facial features for fine-grained ethnicity categorization among closely related East Asian ethnicities. Specifically, we tested the ability of Korean participants to categorize male faces into Korean, Japanese, or Chinese ethnicities—a categorization that according to participants’ own introspective opinion should be easily doable for them. Participants were randomly assigned to one of the three between-subjects conditions: an internal-only condition showing only internal facial features; an external-only condition in which internal features were blurred while hairstyle and face outline remained visible; and a full-face condition presenting both internal and external features. Our findings indicate categorization based on internal features only was barely above chance level, whereas both the full-face and external-only conditions resulted in more reliable above-chance performance—albeit at a low overall level of around 50%. Our study emphasizes the importance of external features in the accurate categorization of ethnic backgrounds, and establishes an overall low ability of Koreans to reliably distinguish between East Asian ethnicities.

The visual system can efficiently process a great amount of visual information, which surpasses computational capacity. One key mechanism for this is ensemble coding, where summary statistical information can be extracted. Another important one is positive serial dependence, where responses to the current stimulus are systematically biased toward the previous one. While these mechanisms are demonstrated to co-occur for fundamental stimuli such as orientations, do these two mechanisms extend to social characteristics of faces, and are the effects consistent across different social characteristics? Here, in this study, we investigated three commonly tested social characteristics (attractiveness, trustworthiness, and dominance). Results from Experiment 1 suggest that positive serial dependence influences the social characteristics perception of face groups. Furthermore, we observe differences in how positive serial dependence affects group perception versus individual face processing, indicating that the perception of group contexts may be dissociated from its components. We further tested with inverted faces in Experiment 2. The results demonstrate that positive serial dependence in group perception for social characteristics of the face relies on both local features and holistic/configural processing from faces. In general, the current study expanded our understanding of serial face perception and perception of face groups.

Uncomfortable visual environments that contain bright colors and striped patterns can induce illusions, headaches, and seizures. However, there is debate surrounding the effects of these environments on visual processing and the individual differences in these effects. We used chromatic grating patterns that differed in their color difference (e.g., red/blue compared to pink/purple) to examine their effects on reading speed – a visually demanding task. One hundred and twelve participants took part, including 25 migraine and 37 headache-free individuals. Reading speed was slower when reading stripy compared to less-stripy text and there was a small non-linear effect of color on reading speed. Individuals with migraine tended to read slower compared to headache-free individuals. We conclude that stripy text negatively affects processing, but color presented in the periphery may not be noxious enough to disrupt processing. The slower reading in migraine highlights the visual demands involved in reading, supporting the need for visually comfortable text.

Facial expressions play a crucial role in social communication, influencing judgments of trustworthiness and competence. While previous research has examined how face masks affect trust and competence in general populations, little is known about their impact on individuals with high autistic traits, who often rely more on the mouth region for social cue interpretation. The present study investigates the effects of face masks on perceptions of trustworthiness and competence as a function of high and low autistic traits. Results show that masked faces are generally perceived as more trustworthy and competent than unmasked faces. The effect of mask wearing on trustworthiness and competence ratings was not affected by autistic traits, suggesting that participants, regardless of their level of autistic traits, adjusted their judgements using available facial cues.

Perceptions of physical attractiveness (PPA) play a significant role in social experiences. Yet most attractiveness research has relied on asking participants to rate the PPA of people they have never, and will never, meet. Evaluation of qualities revealed during social interactions is critical to developing a more comprehensive understanding of PPA as it manifests in naturalistic settings. As an initial step in examining PPA in a social context, we evaluated its association with two highly relevant social variables: extraversion and the smiling of the person being perceived (target). In an exploratory post hoc analysis, we additionally examined the speaking time of the target. This study involved 36-min social interactions among 80 three-person groups of strangers (N = 240). Before the social interaction, participants completed a self-report extraversion measure. After the interaction, they rated the PPA of each of their group members using a 10-point scale. Social interactions were recorded and, with participant permission, were coded for smiling using the Facial Action Coding System and for content-free speech, yielding measures of Duchenne smile duration and speaking time duration. PPA was higher among participants who were more extraverted (β=0.18, p < .01) and who spoke more (β=0.14, p = .02); these predictors remained significant when tested in the same model. Smiling was not a significant predictor of PPA (β=0.08, p = .22). In this initial study of PPA in a small-group context, there was evidence that non-appearance-based factors of the target (personality and speech behavior) also relate to PPA. Future PPA research that assesses multiple streams of verbal and nonverbal influence will offer a fuller understanding of attractiveness perception processes.

This study examined whether attractiveness derived from skeletal indices (skeletal attractiveness) influences facial-attractiveness judgments after makeup application. Three-dimensional facial models were constructed from female faces in the Chicago Face Database (CFD). Based on the anteroposterior positions of the midface and mandible, faces were classified into nine skeletal types and then grouped into high- and low-skeletal-attractiveness categories. A single digital makeup condition, selected through a pretest, was uniformly applied to all faces. Attractiveness ratings were collected online and analyzed using ordinal logistic mixed-effects models with random intercepts for raters and facial identities. Makeup significantly increased attractiveness ratings overall, and faces in the high-skeletal-attractiveness group were rated as more attractive than those in the low group. By contrast, the Makeup  ×  Skeletal Attractiveness Group interaction was not statistically significant, indicating that the makeup-related increase did not clearly differ between the two skeletal groups. Supplementary analyses incorporating target-face perceived age from the CFD norming data showed that faces perceived as older received lower ratings and that makeup-related gains were smaller for older-perceived faces; however, the main conclusions regarding skeletal attractiveness and makeup remained unchanged. These findings suggest that facial-attractiveness judgments are shaped by both surface-based cosmetic cues and three-dimensional structural cues, with skeletal structure functioning primarily as a baseline determinant rather than as a strong moderator of makeup effects.

Two-frame motion defined form is a type of discontinuous motion contrast rendering objects visible through short distance displacement of a region within two otherwise identical sequentially presented random-dot patterns. The resulting illusory object is transiently perceived before fading. The purpose of this study was to benchmark visual spatial acuity for two-frame motion defined form compared to luminance and disparity defined forms. Random dot patterns of equal dot density were used for all contrast types to ensure equivalence of spatial sampling. Stimulus durations in the luminance and stereoscopic conditions were set at the subjective duration (∼270 ms) of the two-frame motion defined form measured in a control experiment. In the main experiment, 25 participants made forced choice judgements on the aspect ratios of the target defined by each of the contrasts using the method of constant stimuli. Participants indicated whether the target square was ‘wider’ or ‘taller’ as a function of the aspect ratio of the target while controlling for trial-to-trial variations in the distance between the vertical/horizontal edges of the target and the boundaries of the surrounding dots. Group mean just-noticeable differences (JNDs) for luminance and stereoscopic conditions translated to changes in aspect ratio of 4.8% and 4%, respectively. They were significantly smaller than the two-frame motion defined condition, 5.8%. Spatial acuity for two-frame motion defined forms is only slightly inferior to other contrast types when equated for spatial sampling and duration. This study is the first benchmark of visual acuity for two-frame motion defined form against luminance and disparity defined form.

Emotional states influence taste perception, yet the knowledge to fully explain this phenomenon remains insufficient. This study investigated this influence in two parts: Experiment 1 focused on the effects of valence and arousal based on the circumplex model of emotions, while Experiment 2 explored a possible mechanism behind valence effects through semantic priming. In Experiment 1, four emotional states were assumed based on valence (positive–negative), arousal (high arousal-low arousal), and taste intensity was measured after evoking each state using video stimuli. In Experiment 2, we investigated the possibility that the influence of emotional valence on taste perception occurs through semantic priming mediated by the association between emotion-taste concepts. Initially, a cognitive task was conducted to modulate the strength of participants’ conceptual associations between emotions and taste qualities. Subsequently, the effect on taste perception following the presentation of either positive or negative auditory stimuli was examined. The results confirmed that emotional valence, rather than arousal, influences the intensity of sweetness and bitterness. Consistent with prior research, the study also verified that the patterns of taste perception change due to emotional states differ between sweetness and bitterness. In particular, the perception of bitterness was found to be intensified by negative emotion through semantic priming, which is mediated by a conceptual association between negative emotion and bitterness.

Alexithymia, a personality trait marked by difficulty in identifying and describing emotions, is associated with differences in interoception – the ability to perceive and interpret internal bodily signals. Interoception plays a key role in forming a coherent sense of self and contributes to body ownership, the feeling that one's body belongs to oneself. This study explored how interoception and alexithymia influence body ownership in immersive virtual reality, particularly under conditions of motor cue congruency. Findings revealed a negative relationship between alexithymia and interoception, and a positive effect of motor synchrony on body ownership. Interoceptive accuracy (assessed via the heartbeat counting task) showed a trend-level positive association with body ownership when virtual and physical movements were aligned. Given the modest sample size (N = 26) and reliance on a single cardiac interoceptive measure, findings should be considered preliminary and warrant replication in larger, multi-method studies.

The tactile perception of wet fabrics plays an important role in human comfort, but the underlying mechanisms of skin–wet fabric interaction remain unclear. This study measured the basic properties (saturated water content, wicking height, moisture regain rate, fabric density, and yarn diameter) of 20 fabrics, collected real-time tactile physical parameters (skin cooling rate, normal pressure, frictional coefficient, maximum acceleration amplitude, and acceleration mean square deviation), and subjective tactile perception ratings (wetness, coldness, roughness, stiffness, and total hand feeling value) during the interactions between fingertip and fabrics with three relative water contents (dry, 35%, and 70% saturated water content). The results demonstrated the significant effects of fabric water content on tactile perceptions and tactile physical parameters. Four machine learning methods, Gradient Boosting Regression, XGBoost Regression, Random Forest Regression, Artificial Neural Networks Regression (ANNR), and a linear regression method, Partial Least Squares Regression, were used to establish predictive models. The ANNR model demonstrated the best performance in total hand feeling value (R² = 0.727, root mean square error = 0.66), and SHapley Additive exPlanations analysis revealed eight key factors, highlighting the significant effect of fabric water content and mechanical stimulation on total hand feeling value. These findings provide deeper insights into enhancing the comfort of wet textiles and offer potential guidance to optimize the tactile design of products.

Studies have found that observers pay less attention to cast shadows in images than to better illuminated regions. In line with such observations, a recent study has suggested stronger change blindness for shadows than for objects (Ehinger et al., 2016). We here examine the role of (overt) visual attention in these findings by recording participants’ eye movements. Participants first viewed all original images (without changes). They then performed a change detection task on a subset of the images with changes in objects or shadows. During both tasks, their eye movements were recorded. In line with the original study, objects (subject to change in the change detection task) were fixated more often than shadows. In contrast to the previous study, better change detection was found for shadows than for objects. The improved change detection for shadows may be explained by the balancing of trials with object and shadow changes in the present study. Eye movements during change detection indicated that participants searched the bottom half of the images. Shadows were more often present in this region, which may explain why they were easier to find.

The superior parietal lobule (SPL) is a region of the brain that has been associated with a diverse range of high-level visual and cognitive functions. This suggested the possibility that it supports a lower-level function that is engaged by a wide range of experimental tasks. Analysis of tasks used in previous studies suggests that one such lower-level function might be the perception of the distance between stimuli in the image plane. In this study, we applied online high-frequency repetitive transcranial magnetic stimulation (rTMS) over the left SPL or the vertex in order to further investigate the role played by this region in the perceived visual separation between points. As a control task, we asked participants to detect the difference in contrast between two Gabor patches. The results failed to support the main hypothesis, but we unexpectedly found that rTMS to left SPL improved peripheral contrast discrimination. Previous studies have found that rTMS to the right frontal eye field, which has strong functional connectivity with the SPL, has the same effect, suggesting the two areas work together to influence early visual areas.