Foveal vision determines the perceived emotion of face ensembles

People can extract summary statistical information from groups of similar objects, an ability called ensemble perception. However, not every object in a group is weighted equally. For example, in ensemble emotion perception, faces far from fixation were weighted less than faces close to fixation. Yet the contribution of foveal input in ensemble emotion perception is still unclear. In two experiments, groups of faces with varying emotions were presented for 100 ms at three different eccentricities (0°, 3°, 8°). Observers reported the perceived average emotion of the group. In two conditions, stimuli consisted of a central face flanked by eight faces (flankers) (central-present condition) and eight faces without the central face (central-absent condition). In the central-present condition, the emotion of the central face was either congruent or incongruent with that of the flankers. In Experiment 1, flanker emotions were uniform (identical flankers); in Experiment 2 they were varied. In both experiments, performance in the central-present condition was superior at 3° compared to 0° and 8°. At 0°, performance was superior in the central-absent (i.e., no foveal input) compared to the central-present condition. Poor performance in the central-present condition was driven by the incongruent condition where the foveal face strongly biased responses. At 3° and 8°, performance was comparable between central-present and central-absent conditions. Our results showed how foveal input determined the perceived emotion of face ensembles, suggesting that ensemble perception fails when salient target information is available in central vision.

Foveal processing of emotion-informative facial features

Certain facial features provide useful information for recognition of facial expressions. In two experiments, we investigated whether foveating informative features of briefly presented expressions improves recognition accuracy and whether these features are targeted reflexively when not foveated. Angry, fearful, surprised, and sad or disgusted expressions were presented briefly at locations which would ensure foveation of specific features. Foveating the mouth of fearful, surprised and disgusted expressions improved emotion recognition compared to foveating an eye or cheek or the central brow. Foveating the brow led to equivocal results in anger recognition across the two experiments, which might be due to the different combination of emotions used. There was no consistent evidence suggesting that reflexive first saccades targeted emotion-relevant features; instead, they targeted the closest feature to initial fixation. In a third experiment, angry, fearful, surprised and disgusted expressions were presented for 5 seconds. Duration of task-related fixations in the eyes, brow, nose and mouth regions was modulated by the presented expression. Moreover, longer fixation at the mouth positively correlated with anger and disgust accuracy both when these expressions were freely viewed (Experiment 2b) and when briefly presented at the mouth (Experiment 2a). Finally, an overall preference to fixate the mouth across all expressions correlated positively with anger and disgust accuracy. These findings suggest that foveal processing of informative features is functional/contributory to emotion recognition, but they are not automatically sought out when not foveated, and that facial emotion recognition performance is related to idiosyncratic gaze behaviour.

Judgments of social awkwardness from brief exposure to children with and without high-functioning autism

We form first impressions of many traits based on very short interactions. This study examines whether typical adults judge children with high-functioning autism to be more socially awkward than their typically developing peers based on very brief exposure to still images, audio-visual, video-only, or audio-only information. We used video and audio recordings of children with and without high-functioning autism captured during a story-retelling task. Typically developing adults were presented with 1 s and 3 s clips of these children, as well as still images, and asked to judge whether the person in the clip was socially awkward. Our findings show that participants who are naïve to diagnostic differences between the children in the clips judged children with high-functioning autism to be socially awkward at a significantly higher rate than their typically developing peers. These results remain consistent for exposures as short as 1 s to visual and/or auditory information, as well as for still images. These data suggest that typical adults use subtle nonverbal and non-linguistic cues produced by children with high-functioning autism to form rapid judgments of social awkwardness with the potential for significant repercussions in social interactions.

The Distinct Role of the Amygdala, Superior Colliculus and Pulvinar in Processing of Central and Peripheral Snakes

Introduction

Visual processing of ecologically relevant stimuli involves a central bias for stimuli demanding detailed processing (e.g., faces), whereas peripheral object processing is based on coarse identification. Fast detection of animal shapes holding a significant phylogenetic value, such as snakes, may benefit from peripheral vision. The amygdala together with the pulvinar and the superior colliculus are implicated in an ongoing debate regarding their role in automatic and deliberate spatial processing of threat signals.

Methods

Here we tested twenty healthy participants in an fMRI task, and investigated the role of spatial demands (the main effect of central vs. peripheral vision) in the processing of fear-relevant ecological features. We controlled for stimulus dependence using true or false snakes; snake shapes or snake faces and for task constraints (implicit or explicit). The main idea justifying this double task is that amygdala and superior colliculus are involved in both automatic and controlled processes. Moreover the explicit/implicit instruction in the task with respect to emotion is not necessarily equivalent to explicit vs. implicit in the sense of endogenous vs. exogenous attention, or controlled vs. automatic processes.

Results

We found that stimulus-driven processing led to increased amygdala responses specifically to true snake shapes presented in the centre or in the peripheral left hemifield (right hemisphere). Importantly, the superior colliculus showed significantly biased and explicit central responses to snake-related stimuli. Moreover, the pulvinar, which also contains foveal representations, also showed strong central responses, extending the results of a recent single cell pulvinar study in monkeys. Similar hemispheric specialization was found across structures: increased amygdala responses occurred to true snake shapes presented to the right hemisphere, with this pattern being closely followed by the superior colliculus and the pulvinar.

Conclusion

These results show that subcortical structures containing foveal representations such as the amygdala, pulvinar and superior colliculus play distinct roles in the central and peripheral processing of snake shapes. Our findings suggest multiple phylogenetic fingerprints in the responses of subcortical structures to fear-relevant stimuli.

Contextualizing Facial Activity

Drawing on research reviewed in this special section, the present article discusses how various contextual factors impact on production and decoding of emotion-related facial activity. Although emotion-related variables often contribute to activation of prototypical “emotion expressions” and perceivers can often infer emotional meanings from these facial configurations, neither process is invariant or direct. Many facial movements are directed towards or away from events in the shared environment, and their effects depend on these relational orientations. Facial activity is not only a medium for descriptive representation of internal affective states, but also a means of adjusting to, and operating on, external objects, and of influencing other people’s appraisals of those objects.

The Role of Gaze in the Processing of Emotional Facial Expressions

Gaze plays a fundamental role in the processing of facial expressions from birth. Gaze direction is a crucial part of the social signal encoded in and decoded from faces. The ability to discriminate gaze direction, already evident early in life, is essential for the development of more complex socially relevant tasks, such as joint and shared attention. At the same time, facial expressions play a fundamental role in the encoding of gaze direction and, when combined, expression and gaze communicate behavioural motivation to approach or avoid. However, the investigation of how gaze direction and emotional expression interact during the processing of a face has been relatively neglected, and is the key question of this review.

Advances in the Study of Facial Expression: An Introduction to the Special Section

For more than a century expressions have been approached as bidimensional, static, instantaneous, self-contained, well-defined, and universal signals. These assumptions are starting to be empirically reconsidered: this special section of Emotion Review includes reviews on the physical, social, and cultural dynamics of expressions, and on the complex ways in which, throughout the lifespan, facial behavior and emotion are perceived and categorized by primates’ and humans’ brain. All these advances are certainly paving the way for new exciting approaches to facial behavior more likely to strike an appropriate balance between description and explanation.