Within-person face recognition strongly correlates with objective face processing assessments: a study beyond the WEIRD populations.

Familiarity plays a pivotal role in within-person face recognition. However, previous research in this field mostly used only one task: Identity Card Sorting. This study aims to explore the links between within-person recognition and other standardized face processing tests, and to extend the sample beyond the WEIRD (western, educated, industrialized, rich and democratic) population. We recruited Taiwanese, Pakistanis and another group of international adults who were neither Taiwanese nor Pakistanis. Each participant completed Face Identity Sorting, Face Discrimination, the Cambridge Face Memory Test (CFMT) and the Prosopagnosia Index (PI-20). Results showed a significant familiarity effect in Face Identity Sorting, with Taiwanese and Pakistani groups, but not the International group, sorting fewer piles for familiar faces (i.e. Pakistani or Taiwanese celebrities). Correlational analyses combining all participants further revealed that Card Sorting performance positively correlated with CFMT and Face Discrimination scores, and showed a marginally negative correlation with PI-20. This suggests that individuals with better face memory and detail-oriented discriminability tend to make fewer errors in the unfamiliar within-person recognition task. This study is the first to examine within-person face recognition in Pakistani and Taiwanese adults, demonstrating a robust effect of familiarity and strong associations with objective assessments of face processing abilities.