# Parallel processing of distinct facial signals for the rapid evaluation of social agents

## TL;DR

The human brain rapidly processes different facial signals, such as emotion and sex, using separate neural mechanisms within less than a tenth of a second.

## Contribution

The study provides empirical evidence for the distributed model of face perception by showing distinct processing timelines for emotional valence and perceived sex.

## Key findings

- The brain distinguishes emotional valence and perceived sex from unfamiliar faces in under 95 ms.
- Emotional valence is decoded earlier than perceived sex, as shown by time-resolved analyses.
- Different facial signals are processed by separate neural mechanisms, supporting the distributed model.

## Abstract

The distributed model of primate face perception proposes that distinct facial signals, such as emotional valence and sex, are processed by separate neural mechanisms. A key prediction is that cues about a face’s emotion and sex are extracted at different processing stages. To test this, we decoded time-resolved patterns of brain activity evoked by a large set of unfamiliar, naturalistic faces. Behavioral ratings were first collected to characterize the perceived emotional valence and sex of 900 faces. Electrophysiological recordings were then obtained while 40 participants passively viewed all face stimuli. The brain reliably distinguished both emotional valence and perceived sex from a brief glance, with decoding emerging in under 95 ms. Crucially, emotional valence showed earlier peak decoding than perceived sex, consistent with time-resolved representational similarity analyses. These findings indicate separable processing pipelines for changeable and stable facial signals, providing empirical support for the distributed model of face perception.

•The human brain extracts facial attributes from the faces of strangers in under 95 ms•Differences in valence are represented earlier in time than differences in perceived sex•Perceived sex relies on different cues in human faces versus non-human faces•Different facial signals are processed by separate neural mechanisms

The human brain extracts facial attributes from the faces of strangers in under 95 ms

Differences in valence are represented earlier in time than differences in perceived sex

Perceived sex relies on different cues in human faces versus non-human faces

Different facial signals are processed by separate neural mechanisms

Social sciences; Psychology