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Waist-to-Hip Ratio Sensitivity in Early Infancy
Hannah White1, Alyson Chroust1, Rachel Jubran1
1Department of Psychology, University of Kentucky, Lexington, Kentucky.
Insights
Female infants show early sensitivity to the waist-to-hip ratio (WHR), preferring attractive body shapes. This preference, observed in 3.5-month-olds, suggests innate body knowledge development and sex differences in social processing.
Area of Science:
- Developmental psychology
- Evolutionary psychology
- Human behavior
Background:
- The waist-to-hip ratio (WHR) is a key indicator of health, attractiveness, and age.
- Adults associate specific WHRs with desirable traits, but developmental origins are unclear.
Purpose of the Study:
- To investigate the developmental emergence of sensitivity to WHR in human infants.
- To determine if infants exhibit preferences for WHRs associated with adult attractiveness.
Main Methods:
- Tested 71 3.5-month-old infants (both male and female) using visual stimuli depicting different WHRs.
- Measured infant looking time preferences between upright and inverted images with varying WHRs.
Main Results:
- Female infants preferred the WHR (0.7) associated with adult attractiveness over a less attractive WHR (0.9).
- This preference was evident only for upright stimuli, ruling out low-level visual cues.
- Male infants did not show a significant WHR preference.
Conclusions:
- Infants possess early sensitivity to WHR, potentially forming a foundation for later social and mate preferences.
- Findings highlight sex differences in early social information processing and body knowledge development.
Abstract:
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.
