Long Lashes, Mixed Signals: Investigating the Effect of Eyelash Length on Perceived Health, Attractiveness, and Sexual Receptivity.

Eyelashes have evolved as a protective feature for the eyes, offering defense against external dangers such as contamination, excessive evaporation, and shear stress from airflow. They may also serve as indicators of an individual's health, since various diseases, both congenital and non-congenital, can influence eyelash length. Building on the argument of evolutionary functionality, recent research into human preferences for eyelash length, from an evolutionary perspective, has identified an inverted-U preference pattern across all ethnic groups. However, this research primarily focused on the attractiveness of eyelash length, leaving questions about the alignment of health perceptions and attractiveness and how eyelash length might signal sexual receptivity unaddressed. The current study aimed to fill these gaps by investigating perceptions of health and sexual receptivity as functions of eyelash length, hypothesizing that while long eyelashes may be rated as less attractive, they could be perceived as signals of sexual receptivity. To explore these questions, participants evaluated the perceived health, attractiveness, and sexual receptivity of female faces from Indian, Asian, Black, and White groups, featuring a range of eyelash lengths from none to half the eye's width. Results confirmed that both health and attractiveness perceptions follow an inverted-U pattern, peaking at eyelash lengths about one-third the width of the eye, consistently across different ethnicities and regardless of the participant's sex. Additionally, results showed that eyelash length is positively associated with perceived sexual receptivity, suggesting that longer eyelashes might signal openness to casual relationships, despite lower attractiveness and health ratings at lengths beyond the optimal one-third ratio. This indicates a potential reproductive strategy linked to wearing long eyelashes and reveals that perceptions of attractiveness and sexual receptivity can diverge.