Redundancy effects in the processing of emotional faces

Opposing aftereffects between a White male face set and a diverse face set

Opposing aftereffects have been observed for faces categorized by gender, race, and age. In order to form opposing aftereffects, it appears that the two face sets must be both physically distinct and differ in terms of social meaning. The current study tests whether (1) a face set that is diverse with respect to sex and race can produce a coherent aftereffect and (2) whether this diversity itself is socially meaningful enough to support opposing aftereffects. Participants adapted to a homogenous face set consisting of only White male Republican congressmen and a diverse face set consisting of White, Asian, Black, and Latino male and female Democratic congress members. Opposing aftereffects were observed: participants adapted simultaneously and in opposite directions to the face sets. These results are the first evidence of adaptation to a face set that varies based on race and sex, and the first evidence of diversity being perceived as a socially meaningful category marker.

Target detection and discrimination in pop-out visual search with two targets

To successfully interact with objects in complex and crowded environments, we often perform visual search to detect or identify a relevant target (or targets) among distractors. Previous studies have reported a redundancy gain when two targets instead of one are presented in a simple target detection task. However, research is scant about the role of multiple targets in target discrimination tasks, especially in the context of visual search. Here, we address this question and investigate its underlying mechanisms in a pop-out search paradigm. In Experiment 1, we directly compared visual search performance for one or two targets for detection or discrimination tasks. We found that two targets led to a redundancy gain for detection, whereas it led to a redundancy cost for discrimination. To understand the basis for the redundancy cost observed in discrimination tasks for multiple targets, we further investigated the role of perceptual grouping (Experiment 2) and stimulus-response feature compatibility (Experiment 3). We determined that the strength of perceptual grouping among homogenous distractors was attenuated when two targets were present compared with one. We also found that response compatibility between two targets contributed more to the redundancy cost compared with perceptual compatibility. Taken together, our results show how pop-out search involving two targets is modulated by the level of feature processing, perceptual grouping, and compatibility of perceptual and response features.

When two faces are not better than one: Serial limited-capacity processing with redundant-target faces

Many researchers believe that faces-whether presented alone or as part of an ensemble-are processed automatically. According to this idea, (a) the detection of single or multiple faces is resource free and does not require allocation of attention, and (b) visual search for faces is held in parallel. The current study put these hypotheses under direct scrutiny. Participants performed in a redundant target-detection task, responding according to the presence or absence of a face (or faces) on the display. I used a rigorous methodology known as the system factorial technology (SFT). The SFT methodology afforded simultaneous assessment of (a) architecture (serial vs. parallel), (b) stopping rule (exhaustive vs. self-terminating), and (c) capacity (limited, unlimited, or supercapacity). SFT analyses were held at the level of the mean RTs and at the level of the RT distributions. The analyses pointed conclusively to a serial self-terminating architecture with limited capacity. These findings cast serious doubts on the alleged automaticity of face perception.

Detection and Recognition of Fearful Facial Expressions During the Coronavirus Disease (COVID-19) Pandemic in an Italian Sample: An Online Experiment

In this observational study, the psychological ability to recognize the others' fearful expressions in Italian individuals during the pandemic COVID-19 lockdown was explored through a behavioral task performed online. An implicit version of the traditional facial emotion recognition task, grounded on the attentional and unconscious mechanism of the redundant target effect, was used. The experiment was scripted through the free software OpenSesame (Mathôt et al., 2012) and published on the Internet through the free software Jatos (Lange et al., 2015). The Reaction Time and level of Accuracy in detecting fearful expressions were computed. Overall, the data of 86 Italian individuals were collected. When their performance was scored in terms of Reaction Time, the redundant target effect did not emerge; instead, the expected effect was observed when the level of Accuracy was considered. Overall, the performance registered in this Italian sample in terms of accuracy was in line with previous results reported in Scarpina et al. (2018), in which a long extended version of the same behavioral task was used in a traditional experimental setting. This study might offer some considerations regarding the adoption of online experiments - together with self-report surveys - to assess the psychological and behavioral functioning during social restriction measures.

Redundancy gain in visual search of simulated X-ray images

Cancer diagnosis frequently relies on the interpretation of medical images such as chest X-rays and mammography. This process is error prone; misdiagnoses can reach a rate of 15% or higher. Of particular interest are false negatives-tumors that are present but missed. Previous research has identified several perceptual and attentional problems underlying inaccurate perception of these images. But how might these problems be reduced? The psychological literature has shown that presenting multiple, duplicate images can improve performance. Here we explored whether redundant image presentation can improve target detection in simulated X-ray images, by presenting four identical or similar images concurrently. Displays with redundant images, including duplicates of the same image, showed reduced false-negative rates, compared with displays with a single image. This effect held both when the target's prevalence rate was high and when it was low. Eye tracking showed that fixating on two or more images in the redundant condition speeded target detection and prolonged search, and that the latter effect was the key to reducing false negatives. The redundancy gain may result from both perceptual enhancement and an increase in the search quitting threshold.

Processing of Individual Items during Ensemble Coding of Facial Expressions

There is growing evidence that human observers are able to extract the mean emotion or other type of information from a set of faces. The most intriguing aspect of this phenomenon is that observers often fail to identify or form a representation for individual faces in a face set. However, most of these results were based on judgments under limited processing resource. We examined a wider range of exposure time and observed how the relationship between the extraction of a mean and representation of individual facial expressions would change. The results showed that with an exposure time of 50 ms for the faces, observers were more sensitive to mean representation over individual representation, replicating the typical findings in the literature. With longer exposure time, however, observers were able to extract both individual and mean representation more accurately. Furthermore, diffusion model analysis revealed that the mean representation is also more prone to suffer from the noise accumulated in redundant processing time and leads to a more conservative decision bias, whereas individual representations seem more resistant to this noise. Results suggest that the encoding of emotional information from multiple faces may take two forms: single face processing and crowd face processing.

Perceiving crowd attention: ensemble perception of a crowd's gaze

In nearly every interpersonal encounter, people readily gather socio-visual cues to guide their behavior. Intriguingly, social information is most effective in directing behavior when it is perceived in crowds. For example, the shared gaze of a crowd is more likely to direct attention than is a single person's gaze. Are people equipped with mechanisms to perceive a crowd's gaze as an ensemble? Here, we provide the first evidence that the visual system extracts a summary representation of a crowd's attention; observers rapidly pooled information from multiple crowd members to perceive the direction of a group's collective gaze. This pooling occurred in high-level stages of visual processing, with gaze perceived as a global-level combination of information from head and pupil rotation. These findings reveal an important and efficient mechanism for assessing crowd gaze, which could underlie the ability to perceive group intentions, orchestrate joint attention, and guide behavior.