Recognizability affects the processing of facial sex information

The different aspects of a face, like sex or identity, can be decoded from the cortical patterns related to its processing. Many studies have investigated this phenomenon with similar outcomes. These studies usually utilize a low number of facial identities and high repetition numbers, which affects the recognizability and familiarity of a face, thus altering the processing. We propose that this commonly employed paradigm influences cortical patterns associated with features seemingly unrelated to identity, such as the sex of a face. In the first experiment, we recreated the findings of previous studies using a few identities and a high presentation number for decoding facial sex. In the second experiment, the identity-presentation ratio was switched. This change resulted in a narrower time window where facial sex related cortical patterns were detected. Decoding accuracy was also diminished, yielding lower values and suggesting a reduced signal-to-noise ratio in the cortex. After expanding the sample size with balanced gender representation, we identified shared cortical patterns related to face-sex processing both within the population and across gender-based subpopulations. These results provide further evidence that familiarity impacts face processing and suggest that previous findings on sex information decoding were likely influenced by the experimental paradigms employed.