The waist‐to‐hip ratio (WHR) is correlated with health and associated with sex, attractiveness, and age judgments by adults. We examined the development of sensitivity to the WHR by testing 3.5‐month‐old infants' (N = 71) preference between images depicting different WHRs. Female 3.5‐month‐olds exhibited a preference for the WHR associated with attractiveness and mate value by adults (0.7) over a larger WHR (0.9). This preference was exhibited when infants were tested on upright stimuli but not when they were tested on inverted stimuli, indicating that low‐level differences (e.g., curviness) were not driving performance. This sensitivity to WHR may lay the foundation for more explicit preferences and categorical associations later in life. In contrast to females, male infants failed to exhibit a significant preference for the 0.7 WHR in either orientation, replicating previous findings of female infants' superior processing of social stimuli. Implications for theories of the development of body knowledge and sex differences in social information processing are discussed.
Highlights
- Waist‐to‐hip ratio (WHR) is a significant social cue for adults, with 0.7 WHR considered ideal for females.
- 3.5‐month‐old female infants preferred 0.7 WHR over 0.9 WHR, but male infants did not exhibit a preference.
- Findings indicate sensitivity to WHR early in life and replicate prior findings of female infants' superior processing of social stimuli.