Summary
Research reveals the importance of lip proportions and appearance in facial attractiveness and the perception of dominance. Kar et al. (2018) highlighted that the ideal ratio between the upper and lower lip height in young Caucasians is 1:1.6. Various studies have found that men with thin lips are perceived as more dominant and attractive, suggesting that a smaller upper lip width is preferable in males. This was supported by a study by Lakhiani & Somenek (2019), which reported that men typically have a thinner upper lip than lower lip, adding to their masculine appeal. Furthermore, a “first impressions” study conducted by Caroline F. Keating at Colgate University involving nearly 300 participants confirmed that thin lips are perceived as more attractive in males than thick ones, reinforcing the preference for a smaller upper lip width in men
Research
The upper lip is part of the lip that stretches from the bottom of the nose to the edges of the smile lines and down to the colored part of the lip. According to Kar et al. (2018), in young Caucasians, the ideal ratio of the vertical height of the upper lip to that of the lower lip is 1:1.6.
The study found that male faces featuring certain mature characteristics such as small eyes and thin lips are seen as more dominant. In terms of attractiveness, men with square jaws and thin lips were rated higher compared to those with round jaws or thick lips. Essentially, thin lips in men are associated with both attractiveness and dominance, making a smaller upper lip width preferable over a larger one.
The study by Lakhiani & Somenek (2019) suggests that men typically have a thinner colored part of the lip (vermilion) compared to the skin part, which makes their upper lip less full than their lower lip. This characteristic lip structure gives a distinct masculine appearance. So, a smaller upper lip width, or thinner upper lip, is considered a masculine trait and is often perceived as more attractive in males.
A “first impressions” study was carried out by Caroline F. Keating at the Colgate University involving 145 male and 154 female subjects demonstrating that thin lips made male faces appear more attractive than thick ones.
Reference
Kar, M., Muluk, N. B., Bafaqeeh, S. A., & Cingi, C. (2018). Is it possible to define the ideal lips?. Acta Otorhinolaryngologica Italica, 38(1), 67. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5952987/
Cunningham, M. R., Barbee, A. P., & Pike, C. L. (1990), University of Louisville. What do women want? Facialmetric assessment of multiple motives in the perception of male facial physical attractiveness. Journal of personality and social psychology, 59(1), 61. https://pubmed.ncbi.nlm.nih.gov/2213490/
Lakhiani, C., & Somenek, M. T. (2019). Gender-related facial analysis. Facial Plastic Surgery Clinics, 27(2), 171-177. https://www.facialplastic.theclinics.com/article/S1064-7406(19)30006-9/fulltext
Keating, C. F. (1985) ‘Gender and the Physiognomy of Dominance and Attractiveness’, Social Psychology Quarterly, 48(1), p. 61. doi: 10.2307/3033782. https://psycnet.apa.org/record/1986-06364-001