Every peer-reviewed study RealSmile cites, mapped to the page that uses it. If a claim on RealSmile is not supported by a study in this list, treat it as opinion, not evidence.
Maintained by Randy, founder of RealSmile. Last verified 2026-05-23.
Willis & Todorov (2006) · Psychological Science
Observers form attractiveness, trustworthiness, competence, and aggressiveness judgments from a face in roughly 100 milliseconds. Longer exposures increase confidence in the initial verdict rather than changing it.
Todorov & Porter (2014) · Psychological Science
Face impressions are formed in as little as 33 milliseconds and are stable across longer exposures. Lighting and pose changes shift the impression by more than the underlying structure does.
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Penton-Voak et al. (2001) · Proceedings of the Royal Society B
Jawline definition and lower-face masculinity are reliable predictors of perceived attractiveness in male faces. The effect is independent of symmetry.
Rhodes (2006) · Annual Review of Psychology
Meta-analysis identifies three structural predictors of facial attractiveness: symmetry, averageness, and sexual dimorphism. Averageness is often the largest single contributor.
Grammer & Thornhill (1994) · Journal of Comparative Psychology
Bilateral facial symmetry is rated as more attractive across cultures and is associated with perceived dominance via the facial width-to-height ratio.
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Ekman & Friesen (1978) · Consulting Psychologists Press
A Duchenne (genuine) smile combines Action Unit 6, orbicularis oculi engagement around the eye, with Action Unit 12, zygomatic major lip-corner pull. Posed smiles use only AU12.
Hamermesh & Biddle (1994) · American Economic Review
Workers rated above average in physical appearance earn roughly 5 percent more, and those rated below average earn roughly 9 percent less, controlling for education and experience.
Langlois & Roggman (1990) · Psychological Science
Composite (averaged) faces are consistently rated more attractive than the individual faces from which they were built. Averageness, not rarity, drives attractiveness.
Carre & McCormick (2008) · Proceedings of the Royal Society B
Facial width-to-height ratio above 2.0 is associated with perceived dominance and aggressive behavior in men.
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Todorov & Olivola (2008) · Scientific American Mind
Snap judgments of competence from a single face photo predict real political election outcomes above chance. The effect generalizes to hiring and partner-selection contexts.
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Geniole et al. (2015) · PLOS ONE
Meta-analysis confirms FWHR signals perceived threat and dominance, but the effect on perceived attractiveness is small and context-dependent.
Zaidel & Cohen (2005) · International Journal of Neuroscience
Lighting direction shifts perceived facial symmetry by up to 23 percent independent of the underlying structure.
Farkas (1994) · Raven Press, New York
Established the normative anthropometric ranges still used in modern facial-analysis tooling: average canthal tilt, gonial angle, facial thirds, and bizygomatic-to-midface ratios.
The face-perception literature is well-established but spread across psychology, anthropology, and economics journals. A single lookup that maps each study to the RealSmile page that uses it makes the citation chain checkable in one click. The studies above are the load-bearing references for the 17-metric audit, the dating-photo audit, the LinkedIn headshot audit, and the four long-tail measurement guides.
For the original-data companion to this index, see the State of Looksmaxxing 2026 data report, which publishes RealSmile's aggregated face-scan distributions alongside the published-research baselines listed above.