Brain Activity Related to the Judgment of Face-Likeness: Correlation between EEG and Face-Like Evaluation

Abstract

Faces represent important information for social communication, because social information, such as face-color, expression, and gender, is obtained from faces. Therefore, individuals' tend to find faces unconsciously, even in objects. Why is face-likeness perceived in non-face objects? Previous event-related potential (ERP) studies showed that the P1 component (early visual processing), the N170 component (face detection), and the N250 component (personal detection) reflect the neural processing of faces. Inverted faces were reported to enhance the amplitude and delay the latency of P1 and N170. To investigate face-likeness processing in the brain, we explored the face-related components of the ERP through a face-like evaluation task using natural faces, cars, insects, and Arcimboldo paintings presented upright or inverted. We found a significant correlation between the inversion effect index and face-like scores in P1 in both hemispheres and in N170 in the right hemisphere. These results suggest that judgment of face-likeness occurs in a relatively early stage of face processing.

Face pareidolia in the brain: Impact of gender and orientation

“…This finding dovetails well with common visual experience with Arcimboldo portraits: visual processing is affected by display inversion in such a way that they are perceived simply as a composition of fruits and vegetables. Display inversion decreases face-likeness scores of faces, Arcimboldo portraits, and face-like images of cars and insects [18]. EEG shows that while with canonical display orientation, no difference occurs in the amplitude of P1, N170, and N250 components of ERPs for all types of stimuli, display inversion leads to a significant increase in the N170 amplitude in the right hemisphere for real faces solely.…”

“…Obviously, the networks for processing of upright and inverted faces are topographically overlapping: for example, the occipital face area (OFA) is involved in the processing of both upright and inverted faces [65,66]. MEG and EEG underscore the main difference in processing of upright and inverted faces in the time course of unfolding brain PLOS ONE activation rather than in topography of engaged brain regions solely [18,29]. Latencies of brain responses to inverted compared to upright faces are longer in the right and shorter in the left hemisphere [67].…”

“…Such preference in species with no parental care advocates the existence of a general mechanism to detect animacy in the natural environment [12]. Brain imaging such as functional magnetic resonance imaging, fMRI [13,14], magnetoencephalography, MEG [15], and electroencephalography, EEG [16][17][18][19] reveal that real faces and face-like nonface images activate similar occipito-temporal brain clusters with a hub in the fusiform face area, FFA (for review, see [20,21]). Face impression in such images usually arises spontaneously without any efforts.…”

“…This experimental manipulation is rather extensively used in face perception research, in particular, in infants and patient populations (e.g., preferential looking with simultaneously presented upright and inverted faces is used instead of tools based on verbal or motor responses that are impossible or difficult to collect) and brain imaging (e.g., the passive viewing paradigm is implemented with a set of upright and inverted faces). Although previous (yet rather scarce) work with face-like non-face images also uses inverted displays [18,46,47], it has not been directed at studying the impact of inversion on recognition of face-like non-face images per se. Instead, most studies take for granted that display inversion generally deteriorates face impression in such images.…”

Face neurons in human visual cortex

“…To further interrogate tuning of facial features at the single-cell level, we capitalized on the phenomenon of face pareidolia (Figure 6A), the compelling illusion of perceiving illusory facial features in inanimate objects, which is experienced by both humans (J. Liu et al, 2014; Nihei, Minami, & Nakauchi, 2018; Wardle, Seymour, & Taubert, 2017) and macaque monkeys (Taubert, Wardle, Flessert, Leopold, & Ungerleider, 2017). This phenomenon is relevant because, unlike real faces, examples of face pareidolia (hereafter referred to as ‘face-like objects’) have facial features that are highly variable in terms of their visual attributes.…”