It is hypothesized that human faces judged to be attractive by people possess two features—averageness and symmetry—that promoted adaptive mate selection in human evolutionary history by way of production of offspring with parasite resistance. Facial composites made by combining individual faces are judged to be attractive, and more attractive than the majority of individual faces. The composites possess both symmetry and averageness of features. Facial averageness may reflect high individual protein heterozygosity and thus an array of proteins to which parasites must adapt. Heterozygosity may be an important defense of long-lived hosts against parasites when it occurs in portions of the genome that do not code for the essential features of complex adaptations. In this case heterozygosity can create a hostile microenvironment for parasites without disrupting adaptation. Facial bilateral symmetry is hypothesized to affect positive beauty judgments because symmetry is a certification of overall phenotypic quality and developmental health, which may be importantly influenced by parasites. Certain secondary sexual traits are influenced by testosterone, a hormone that reduces immunocompetence. Symmetry and size of the secondary sexual traits of the face (e.g., cheek bones) are expected to correlate positively and advertise immunocompetence honestly and therefore to affect positive beauty judgments. Facial attractiveness is predicted to correlate with attractive, nonfacial secondary sexual traits; other predictions from the view that parasite-driven selection led to the evolution of psychological adaptations of human beauty perception are discussed. The view that human physical attractiveness and judgments about human physical attractiveness evolved in the context of parasite-driven selection leads to the hypothesis that both adults and children have a species-typical adaptation to the problem of identifying and favoring healthy individuals and avoiding parasite-susceptible individuals. It is proposed that this adaptation guides human decisions about nepotism and reciprocity in relation to physical attractiveness.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
Alexander, J., and W. H. Stimson 1988 Sex Hormones and the Course of Parasitic Infection.Parasitology Today 4:189–193.
Alley, T. R., and M. R. Cunningham 1991 Averaged Faces Are Attractive, but Very Attractive Faces Are Not Average.Psychological Science 2:123–125.
Alley, T. R., and K. A. Hildebrandt 1988 Determinants and Consequences of Facial Aesthetics. InSocial and Applied Aspects of Perceiving Faces, T. R. Alley, ed. Pp. 101–140. Hillsdale, New Jersey: Lawrence Erlbaum Associates.
Anderson, R. M., and R. M. May 1982 Coevolution of Hosts and Parasites.Parasitology 85:411–426.
1983 Epidemiology and Genetics in the Coevolution of Parasites and Hosts.Proceedings of the Royal Society of London B 219:281–313.
Bailit, H. L., P. L. Workman, J. D. Niswander, and J. C. Maclean 1970 Dental Asymmetry as an Indicator of Genetic and Environmental Conditions in Human Populations.Human Biology 42:626–638.
Behnke, J. M. 1990Parasites: Immunity and Pathology. London: Taylor and Francis.
Bell, G. 1982The Masterpiece of Nature: The Evolution and Genetics of Sexuality. Berkeley: University of California Press.
Bell, G., and J. Maynard Smith 1987 Short-term Selection for Recombination among Mutually Antagonistic Species.Nature 328:66–68.
Bernstein, I. H., T. Lin, and P. McClellan 1982 Cross-and Within-racial Judgments of Attractiveness.Perception and Psychophysics 32:495–503.
Borgerhoff Mulder, M. 1990 Kipsigis Women Prefer Wealthy Men: Evidence for Female Choice in Mammals?Behavioral Ecology and Sociobiology 27:255–264.
Borgia, G. 1979 Sexual Selection and the Evolution of Mating Systems. InSexual Selection and Reproductive Competition in Insects. M. S. Blum and N. A. Blum, eds. Pp. 19–80. New York: Academic Press.
Bradbury, J., and M. Andersson, eds. 1987Sexual Selection: Testing the Alternatives. New York: John Wiley and Sons.
Burt, A., and G. Bell 1987 Mammalian Chiasma Frequencies as a Test of Two Theories of Recombination.Nature 326:803–805.
Buss, D. M. 1989 Sex Differences in Human Mate Preferences: Evolutionary Hypotheses Testing in 37 Cultures.Behavioral and Brain Sciences 12:1–14.
Charlesworth, B. 1988 The Evolution of Mate Choice in a Fluctuating Environment.Journal of Theoretical Biology 130:191–204.
Cunningham, M. R. 1986 Measuring the Physical in Physical Attractiveness: Quasi-experiments on the Sociobiology of Female Facial Beauty.Journal of Personality and Social Psychology 50:925–935.
Cunningham, M. R., A. P. Barbee, and C. L. Pike 1990 What Do Women Want? Facialmetric Assessment of Multiple Motives in the Perception of Male Facial Physical Attractiveness.Journal of Personality and Social Psychology 59:61–72.
Dabbs, J. M., Jr., and R. Morris 1990 Testosterone, Social Class and Antisocial Behavior in a Sample of 4,462 Men.American Psychological Society 1:209–211.
Dengrove, E. 1961 Sex Differences. InThe Encyclopedia of Sexual Behavior, Vol. 2, A. Ellis and A. Abarbanel, eds. Pp. 931–938. London: Corsano.
Dion, K., E. Berscheid, and E. Walster 1972 What Is Beautiful Is Good.Journal of Personality and Social Psychology. 24:285–290.
Eagly, A. H., R. D. Ashmore, M. G. Makhijani, and L. C. Longo 1991 What Is Beautiful Is Good, But....: A Meta-analytic Review of Research on the Physical Attractiveness Stereotype.Psychological Bulletin 110:109–128.
Eshel, I., and W. D. Hamilton 1984 Parent-offspring Correlation in Fitness under Fluctuating Selection.Proceedings of the Royal Society of London B 222:1–14.
Essock-Vitale, S. M. 1984 The Reproductive Success of Wealthy Americans.Ethology and Sociobiology 5:45–49.
Farr, J. A. 1983 The Inheritance of Quantitative Fitness Traits in Guppies,Poecilia reticulata (Pisces: Poecilidae).Evolution 37:1193–1209.
Feingold, A. 1990 Gender Differences in Effects of Physical Attractiveness on Romantic Attraction: A Comparison across Five Research Paradigms.Journal of Personality and Social Psychology 59:981–993.
Fisher, R. A. 1958The Genetical Theory of Natural Selection, 2nd ed. Oxford: Clarendon Press.
Fölstad, I., and A. J. Karter 1992 Parasites, Bright Males and the Immunocompetence Handicap.American Naturalist 139:603–622.
Freeland, W. J. 1976 Pathogens in the Evolution of Primate Sociality.Biotropica 8:12–24.
Gangestad, S. W., and D. M. Buss In press Pathogen Prevalence and Human Mate Preferences.Ethology and Sociobiology.
Gangestad, S. W., R. Thornhill, and R. A. Yeo In press Facial Attractiveness, Developmental Stability and Fluctuating Asymmetry.Ethology and Sociobiology.
Glesener, R. R., and D. Tilman 1978 Sexuality and the Components of Environmental Uncertainty: Clues from Geographic Parthenogenesis in Terrestrial Animals.American Naturalist 112:659–673.
Goldman, W., and P. Lewis 1977 Beautiful Is Good: Evidence that the Physically Attractive Are More Socially Skilled.Journal of Experimental Social Psychology 13:125–130.
Grammer, K., and R. Thornhill 1993 Human Facial Attractiveness and Sexual Selection: The Roles of Averageness and Symmetry. Ms. in authors’ possession. Submitted for publication.
Grossmann, C. J. 1985 Interactions between the Gonadal Steroids and the Immune System.Science 227:257–261.
Hamilton, W. D. 1980 Sex versus Non-sex versus Parasite.Oikos 35:282–290.
1993 Inbreeding in Egypt and in This Book. InThe Natural History of Inbreeding and Outbreeding: Theoretical and Empirical Perspectives. N. W. Thornhill, ed. Chicago: University of Chicago Press.
Hamilton, W. D., and M. Zuk 1982 Heritable True Fitness and Bright Birds: A Role for Parasites?Science 218:384–387.
Hausfater, G., and R. Thornhill 1990 Parasites and Sexual Selection (editors’ introduction).American Zoologist 30:2.
Herman, C. P., M. P. Zanna, and E. Tory Higgins, eds. 1986Physical Appearance, Stigma and Social Behavior. Hillsdale, New Jersey: Lawrence Erlbaum Associates.
Hill, A. V. S, C. E. M. Allsopp, D. Kwiatkowski, N. M. Anstey, P. Twumasi, P. A. Rowe, S. Bennett, D. Brewster, A. J. McMichael, and B. M. Greenwood 1991 Common West African HLA Antigens Are Associated with Protection from Severe Malaria.Nature 352:595–600.
Hole, J. W., Jr. 1987Human Anatomy and Physiology, 4th ed. Dubuque, Iowa: Wm. C. Brown.
Howard, J. C. 1991 Disease and Evolution.Nature 352:565–567.
Hubschman, J. H., and M. A. Stack 1992 Parasite-induced Changes inChironomus decorus (Diptera: Chironomidae).Journal of Parasitology 78:872–875.
Jaenike, J. 1978 An Hypothesis to Account for the Maintenance of Sex with Populations.Evolutionary Theory 3:191–194.
Johnston, V. S., and M. Franklin In press Is Beauty in the Eye of the Beholder?Ethology and Sociobiology.
Jones, J. S. 1987 An Asymmetrical View of Fitness.Nature 325:298–299.
Kaplan, H., and K. Hill 1985 Hunting Ability and Reproductive Success among Male Ache Foragers.Current Anthropology 26:131–133.
Kennedy, C. E. J., J. A. Endler, S. L. Poyton, and H. McMinn 1987 Parasite Load Predicts Mate Choice in Guppies.Behavioral Ecology and Sociobiology 21:291–295.
Kirkpatrick, M. 1987 Sexual Selection by Female Choice in Polygynous Animals.Annual Review of Ecology and Systematics 18:43–70.
Kodric-Brown, A., and M. E. Hohmann 1990 Sexual Selection Is Stabilizing Selection in Pupfish (Cyprinodon pecosensis).Biological Journal of the Linnean Society 40:113–123.
Ladle, R. J. 1992 Parasites and Sex: Catching the Red Queen.Trends in Ecology and Evolution 7:405–408.
Langlois, J. H., and L. A. Roggman 1990 Attractive Faces Are Only Average.Psychological Science 1:115–121.
Lerner, I. M. 1954Genetic Homeostatis. Edinburgh: Oliver and Boyd.
Leary, R. F., and F. W. Allendorf 1989 Fluctuating Asymmetry as an Indicator of Stress: Implications for Conservation Biology.Trends in Ecology and Evolution 4:214–217.
Levin, D. A. 1975 Pest Pressure and Recombination Systems in Plants.American Naturalist 109:437–451.
Livshits, G., and E. Kobyliansky 1991 Fluctuating Asymmetry as a Possible Measure of Developmental Homeostasis in Humans: A Review.Human Biology 63:441–466.
Low, B. S. 1990 Marriage Systems and Pathogen Stress in Human Societies.American Zoologist 30:325–339.
Loye, J. E., and M. Zuk, eds. 1991Bird-Parasite Interactions: Ecology, Behavior and Evolution. Oxford: Oxford University Press.
Manning, J. T., and A. T. Chamberlain In press Fluctuating Asymmetry, Sexual Selection and Canine Teeth in Primates.Proceedings of the Royal Society of London B.
Manning, J. T., and M. A. Hartley 1991 Symmetry and Ornamentation Are Correlated in the Peacock’s Train.Animal Behaviour 42:1020–1021.
Maret, S. M. 1983 Attractiveness Ratings of Photographs of Blacks by Cruzans and Americans.The Journal of Psychology 115:113–116.
Maret, S. M., and G. A. Harling 1985 Cross-cultural Perceptions of Physical Attractiveness: Ratings of Photos of Whites by Cruzans and Americans.Perceptual and Motor Skills 60:163–166.
Markow, T. A., and J. P. Ricker 1992 Male Size, Developmental Stability and Mating Success in Natural Populations on ThreeDrosophila Species.Heredity 69:122–127.
Maruyama, G., and N. Miller 1981 Physical Attractiveness and Personality. InProgress in Experimental Personality Research, vol. 10, B. A. Maher and W. B. Maher, eds. Pp. 203–280. New York: Academic Press.
Maynard Smith, J. 1978The Evolution of Sex. Cambridge: Cambridge University Press.
McMinn, H. 1990 Effects of the Nematode ParasiteCamallanus cotti on Sexual and Nonsexual Behaviors in the Guppy (Poecilia reticulata).American Zoologist 30:245–249.
Mitton, J. B. 1993 Theory and Data Pertinent to the Relationship between Heterozygosity and Fitness. InThe Natural History of Inbreeding and Outbreeding: Theoretical and Empirical Perspectives, N. W. Thornhill, ed. Chicago: University of Chicago Press.
Mitton, J. B., and M. C. Grant 1984 Associations among Protein Heterozygosity, Growth Rate and Developmental Homeostasis.Annual Review of Ecology and Systematics 15:479–499.
Mitton, J. B., W. S. F. Schuster, E. G. Cothran, and J. C. De Fries In press the Correlation between the Individual Heterozygosity of Parents and Their Offspring.Heredity.
Møller, A. P. 1988 Female Choice Selects for Male Sexual Tail Ornaments in the Monogamous Swallow.Nature 332:640–642.
1990a Parasites and Sexual Selection: Current Status of the Hamilton and Zuk Hypothesis.Journal of Evolutionary Biology 3:319–328.
1990b Fluctuating Asymmetry in Male Sexual Ornaments May Reliably Reveal Male Quality.Animal Behaviour 40:1185–1187.
1990c Male Tail Length and Female Mate Choice in the Monogamous SwallowHirundo rustica.Animal Behaviour 39:458–465.
1990d Effects of a Haematophagus Mite on the Barn Swallow (Hirundo rustica): A Test of the Hamilton and Zuk Hypothesis.Evolution 44:771–784.
1992a Female Swallow Preference for Symmetrical Male Sexual Ornaments.Nature 357:238–240.
1992b Patterns of Fluctuating Asymmetry in Weapons: Evidence for Reliable Signalling of Quality in Beetle Horns and Bird Spurs.Proceedings of the Royal Society of London B 248:199–206.
In press Parasites Differentially Increase the Degree of Fluctuating Asymmetry in Secondary Sexual Characters.Journal of Evolutionary Biology.
Møller, A. P., and J. Höglund 1991 Patterns of Fluctuating Symmetry in Avian Feather Ornaments: Implications for Modeling Sexual Selection.Proceedings of the Royal Society of London B 245:1–5.
Møller, A. P., and A. Pomiankowski In press Fluctuating Asymmetry and Sexual Selection.Genetica.
O’Brien, S. J., and J. F. Evermann 1988 The Interface of Epidemiology and Genetic Diversity in Free-Ranging Animal Populations.Trends in Ecology and Evolution 3:254–259.
Palmer, R. A., and C. Strobeck 1986 Fluctuating Asymmetry: Measurement, Analysis, Patterns.Annual Review of Ecology and Systematics 17:391–421.
Parsons, P. A. 1990 Fluctuating Asymmetry: An Epigenetic Measure of Stress.Biological Review 65:131–145.
Partridge, L. 1983 Non-random Mating and Offspring Fitness. InMate Choice, P. Bateson, ed. Pp. 227–255. Cambridge: Cambridge University Press.
Petrie, M., T. R. Halliday, and C. Sanders 1991 Peahens Prefer Peacocks with Elaborate Trains.Animal Behaviour 41:323–331.
Polak, M. In press Parasitic Infection Increases Fluctuating Asymmetry of MaleDrosophila nigrospiracula: Implications for Sexual Selection.Genetica.
Potts, W. K., C. Jo Manning, and E. K. Wakeland 1991 Mating Patterns in Semi-natural Populations of Mice Influenced by MHC Genotype.Nature 352:619–621.
Rice, W. R. 1983 Parent-offspring Pathogen Transmission: A Selective Agent Promoting Sexual Reproduction.American Naturalist 121:187–203.
Sauer, K. P., R. Thornhill, and S. Fleck In press On the Genetic Relationships between a Zahavian Handicap of Fathers and Offspring Quality in a Scorpionfly.Behavioral Ecology and Sociobiology.
Seger, J., and W. D. Hamilton 1988 Parasites and Sex. InThe Evolution of Sex, R. E. Michod and B. R. Levin, eds. Pp. 14–31. Sunderland, Massachusetts: Sinauer Associates.
Sherman, P. W., T. D. Seeley, and H. K. Reeve 1988 Parasites, Pathogens and Polyandry in Social Hymenoptera.American Naturalist 131:602–610.
Sigall, H., and D. Landy 1973 Radiating Beauty: The Effects of Having a Physically Attractive Partner on Person Perception.Journal of Personality and Social Psychology 28:218–224.
Simpson, J. A., and S. W. Gangestad 1992 Sociosexuality and Romantic Partner Choice.Journal of Personality 60:31–51.
Singh, D. In press Adaptive Significance of Female Physical Attractiveness: Role of Waist-to-hip Ratio (WHR).Journal of Personality and Social Psychology.
Slade, R. W. 1992 Limited MHC Polymorphism in the Southern Elephant Seal: Implications for MHC Evolution and Marine Mammal Population Biology.Proceedings of the Royal Society of London B 249:163–171.
Snyder, M., E. D. Tanke, and E. Berscheid 1977 Social Behavior and Interpersonal Perception: On the Self-Fulfilling Nature of Social Stereotypes.Journal of Personality and Social Psychology 35:656–666.
Soulé, M. 1982 Allometric Variation, 1: The Theory and Some Consequences.American Naturalist 120:751–764.
Soulé, M., and J. Cuzin-Roudy 1982 Allometric Variation, 2: Developmental Instability of Extreme Phenotypes.American Naturalist 120:765–786.
Strzalko, J., and K. A. Kaszycka 1991 Physical Attractiveness: Interpersonal and Intrapersonal Variability of Assessments.Social Biology 39:170–176.
Symons, D. 1979The Evolution of Human Sexuality. Oxford: Oxford University Press.
1987 An Evolutionary Approach: Can Darwin’s View of Life Shed Light on Human Sexuality? InTheories of Human Sexuality, J. H. Geer and W. T. O’Donohue, eds. Pp. 91–125. New York: Plenum Press.
Thiessen, D., and B. Gregg 1980 Human Assortative Mating and Genetic Equilibrium: An Evolutionary Perspective.Ethology and Sociobiology 1:111–140.
Thanakar, J. N., and S. Iwakawi 1979 Cross-cultural Comparisons in Interpersonal Attraction of Females Toward Males.Journal of Social Psychology 108:121–122.
Thornhill, N. W., ed. 1993The Natural History of Inbreeding and Outbreeding: Theoretical and Empirical Perspectives. Chicago: University of Chicago Press.
Thornhill, R. 1992a Fluctuating Asymmetry and the Mating System of the Japanese Scorpionfly,Panorpa japonica.Animal Behaviour 44:867–879.
1992b Female Preference for the Pheromone of Males with Low Fluctuating Asymmetry in the Japanese Scorpionfly (Panorpa japonica: Mecoptera).Behavioral Ecology 3:277–283.
1992c Fluctuating Asymmetry, Interspecific Aggression and Male Mating Tactics in Two Species of Japanese Scorpionflies.Behavioral Ecology and Sociobiology 30:357–363.
Thornhill, R., and J. Alcock 1983The Evolution of Insect Mating Systems. Cambridge: Harvard University Press.
Thornhill, R., and K. P. Sauer 1991 The Notal Organ of the ScorpionflyPanorpa vulgaris: An Adaptation to Coerce Mating Duration.Behavioral Ecology 2:156–164.
1992 Paternal Effects on the Fighting Ability of Sons and Daughters and the Mating Success of Sons in a Scorpionfly.Animal Behaviour 43:255–264.
Thornhill, R., and N. W. Thornhill 1983 Human Rape: An Evolutionary Analysis.Ethology and Sociobiology 4:137–173.
Tooby, J. 1982 Pathogens, Polymorphism and the Evolution of Sex.Journal of Theoretical Biology 97:557–576.
Tooby, J., and L. Cosmides 1990 On the Universality of Human Nature and the Uniqueness of the Individual: The Role of Genetics and Adaptations.Journal of Personality 58:17–67.
Townsend, J. M., and G. D. Levy 1990 Effects of Potential Partners’ Physical Attractiveness and Socioeconomic Status on Sexuality and Partner Selection: Sex Differences in Reported Preferences of University Students.Archives of Sexual Behavior 19:149–164.
Trivers, R. L. 1972 Parental Investment and Sexual Selection. InSexual Selection and the Descent of Man, 1871–1971, B. Campbell, ed. Pp. 136–179. Chicago: Aldine.
1985Social Evolution. Menlo Park, California: Benjamin/Cummings.
Walster, E., V. Aronson, D. Abrahams, and L. Rottman 1966 Importance of Physical Attractiveness in Dating Behavior.Journal of Personality and Social Psychology 4:508–516.
Watson, P. W., and R. Thornhill In press Fluctuating Asymmetry and Sexual Selection.Trends in Ecology and Evolution.
Watt, W. B., P. A. Carter, and K. Donohue 1986 Females’ Choice of “Good Genotypes” as Mates Is Promoted by an Insect Mating System.Science 233:1187–1190.
Watt, W. B., R. C. Cassin, and M. S. Swan 1983 Adaptation of Specific Loci, III: Field Behavior and Survivorship Differences amongColias PGI Genotypes Are Predictable fromin vitro Biochemistry.Genetics 103:725–739.
Wedekind, C. 1992 Detailed Information about Parasites Revealed by Sexual Ornamentation.Proceedings of the Royal Society of London B 247:169–174.
Williams, G. C. 1966Adaptation and Natural Selection. Princeton, New Jersey: Princeton University Press.
1975Sex and Evolution. Princeton, New Jersey: Princeton University Press.
Zahavi, A. 1975 Mate Selection: A Selection for a Handicap.Journal of Theoretical Biology 53:205–214.
Zakharov, V. M. 1989 Future Prospects for Population Phenogenetics.Soviet Scientific Reviews, Section F, Physiology and General Biology Reviews 4(3):1–79.
Zakharov, V. M., E. Pankakoski, B. I. Sheftel, A. Peltonen, and I. Hanski 1991 Developmental Stability and Population Dynamics in the Common Shrew.American Naturalist 138:797–810.
Zuk, M. 1990 Reproductive Strategies and Disease Susceptibility: An Evolutionary Viewpoint.Parasitology Today 6:231–233.
1992 The Role of Parasites in Sexual Selection: Current Evidence and Future Directions.Advances in the Study of Behavior 21:39–67.
Zuk, M., K. Johnson, R. Thornhill, and J. D. Ligon 1990 Parasites and Male Ornaments in Free-ranging and Captive Red Jungle Fowl.Behavior 114:232–248.
Randy Thornhill is a professor of biology at the University of New Mexico, Albuquerque. His research interests include insect behavioral ecology, human sexual behavior and psychology, characterizing the process of sexual selection, and the study of adaptation and methodology in evolutionary biology in general. Recently, he has focused research on the beauty of human bodily form and the role of fluctuating asymmetry in sexual selection.
Steven W. Gangestad is an associate professor of psychology at the University of New Mexico. His recent research includes work focused on sexual selection in humans and its implications for general relationship phenomena. His other recent research concerns the impact of developmental instability on functional asymmetries, interpersonal orientations, and individual differences in the control of emotional expression.
About this article
Cite this article
Thornhill, R., Gangestad, S.W. Human facial beauty. Human Nature 4, 237–269 (1993). https://doi.org/10.1007/BF02692201
- Fluctuating asymmetry
- Mate choice
- Sexual reproduction