Searching for people: Non-facing distractor pairs hinder the visual search of social scenes more than facing distractor pairs

Invisible social grouping facilitates the recognition of individual faces

Emerging evidence suggests a specialized mechanism supporting perceptual grouping of social entities. However, the stage at which social grouping is processed is unclear. Through four experiments, here we showed that participants' recognition of a visible face was facilitated by the presence of a second facing (thus forming a social grouping) relative to a nonfacing face, even when the second face was invisible. Using a monocular/dichoptic paradigm, we further found that the social grouping facilitation effect occurred when the two faces were presented dichoptically to different eyes rather than monocularly to the same eye, suggesting that social grouping relies on binocular rather than monocular neural channels. The above effects were not found for inverted face dyads, thereby ruling out the contribution of nonsocial factors. Taken together, these findings support the unconscious influence of social grouping on visual perception and suggest an early origin of social grouping processing in the visual pathway.

Is the social chunking of agent actions in working memory resource-demanding?

Retaining social interactions in working memory (WM) for further social activities is vital for a successful social life. Researchers have noted a social chunking phenomenon in WM: WM involuntarily uses the social interaction cues embedded in the individual actions and chunks them as one unit. Our study is the first to examine whether the social chunking in WM is an automatic process, by asking whether social chunking of agent actions in WM is resource-demanding, a key hallmark of automaticity. We achieved this by probing whether retaining agent interactions in WM as a chunk required more attention than retaining actions without interaction. We employed a WM change-detection task with actions containing social interaction cues as memory stimuli, and required participants only memorizing individual actions. As domain-general attention and object-based attention are suggested playing a key role in retaining chunks in WM, a secondary task was inserted in the WM maintenance phase to consume these two types of attention. We reestablished the fact that the social chunking in WM required no voluntary control (Experiments 1 and 2). Critically, we demonstrated substantial evidence that social chunking in WM did not require extra domain-general attention (Experiment 1) or object-based attention (Experiment 2). These findings imply that the social chunking of agent actions in WM is not resource-demanding, supporting an automatic view of social chunking in WM.

How does the presence of a surgical face mask impair the perceived intensity of facial emotions?

The use of surgical-type face masks has become increasingly common during the COVID-19 pandemic. Recent findings suggest that it is harder to categorise the facial expressions of masked faces, than of unmasked faces. To date, studies of the effects of mask-wearing on emotion recognition have used categorisation paradigms: authors have presented facial expression stimuli and examined participants’ ability to attach the correct label (e.g., happiness, disgust). While the ability to categorise particular expressions is important, this approach overlooks the fact that expression intensity is also informative during social interaction. For example, when predicting an interactant’s future behaviour, it is useful to know whether they are slightly fearful or terrified, contented or very happy, slightly annoyed or angry. Moreover, because categorisation paradigms force observers to pick a single label to describe their percept, any additional dimensionality within observers’ interpretation is lost. In the present study, we adopted a complementary emotion-intensity rating paradigm to study the effects of mask-wearing on expression interpretation. In an online experiment with 120 participants (82 female), we investigated how the presence of face masks affects the perceived emotional profile of prototypical expressions of happiness, sadness, anger, fear, disgust, and surprise. For each of these facial expressions, we measured the perceived intensity of all six emotions. We found that the perceived intensity of intended emotions (i.e., the emotion that the actor intended to convey) was reduced by the presence of a mask for all expressions except for anger. Additionally, when viewing all expressions except surprise, masks increased the perceived intensity of non-intended emotions (i.e., emotions that the actor did not intend to convey). Intensity ratings were unaffected by presentation duration (500ms vs 3000ms), or attitudes towards mask wearing. These findings shed light on the ambiguity that arises when interpreting the facial expressions of masked faces.

The spatial distance compression effect is due to social interaction and not mere configuration

In recent years, there has been a surge of interest in perception, evaluation, and memory for social interactions from a third-person perspective. One intriguing finding is a spatial distance compression effect when target dyads are facing each other. Specifically, face-to-face dyads are remembered as being spatially closer than back-to-back dyads. There is a vibrant debate about the mechanism behind this effect, and two hypotheses have been proposed. According to the social interaction hypothesis, face-to-face dyads engage a binding process that represents them as a social unit, which compresses the perceived distance between them. In contrast, the configuration hypothesis holds that the effect is produced by the front-to-front configuration of the two visual targets. In the present research we sought to test these accounts. In Experiment 1 we successfully replicated the distance compression effect with two upright faces that were facing each other, but not with inverted faces. In contrast, we found no distance compression effect with three types of nonsocial stimuli: arrows (Experiment 2a), fans (Experiment 2b), and cars (Experiment 3). In Experiment 4, we replicated this effect with another social stimuli: upright bodies. Taken together, these results provide strong support for the social interaction hypothesis.

The Twenty Item Prosopagnosia Index (PI20) provides meaningful evidence of face recognition impairment

The Twenty Item Prosopagnosia Index (PI20) is a self-report questionnaire used for quantifying prosopagnosic traits. This scale is intended to help researchers identify cases of developmental prosopagnosia by providing standardized self-report evidence to complement diagnostic evidence obtained from objective computer-based tasks. In order to respond appropriately to items, prosopagnosics must have some insight that their face recognition is well below average, while non-prosopagnosics need to understand that their relative face recognition ability falls within the typical range. There has been considerable debate about whether participants have the necessary insight into their face recognition abilities to respond appropriately. In the present study, we sought to determine whether the PI20 provides meaningful evidence of face recognition impairment. In keeping with the intended use of the instrument, we used PI20 scores to identify two groups: high-PI20 scorers (those with self-reported face recognition difficulties) and low-PI20 scorers (those with no self-reported face recognition difficulties). We found that participant groups distinguished on the basis of PI20 scores clearly differed in terms of their mean performance on objective measures of face recognition ability. We also found that high-PI20 scorers were more likely to achieve levels of face recognition accuracy associated with developmental prosopagnosia.