Fluctuating asymmetry (FA) is small deviations from perfect symmetry in normally bilaterally symmetrical traits. We examined the relationship between FA of five body traits (ear height, length of three digits, and ankle circumference) and self-reported scores of physical and verbal aggression in a sample of 90 boys aged 10 to 15 years. The relationships between FA and scores of aggression (particularly physical aggression) were found to be negative; in other words, the most symmetrical boys showed highest aggression. One trait (ankle circumference) showed the characteristics of “ideal” FA—parametric mean of zero and a normal distribution. Mean asymmetries calculated from six repeated measures of ankle FA in 30 subjects taken over a period of five months showed strong negative associations with scores of physical aggression which were independent of age, height, and weight.
It is argued that soft tissue “cyclical” FA (as opposed to “fixed” bony FA) is dependent on the secretion of hormones: for example, cortisol. Causal associations between behavioral traits such as aggresion and hormones will lead to similar correlations between FA and behavior.
Key wordsAggression Cortisol Fluctuating asymmetry Hormonal fluctuation Testosterone
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- Archer, J. 1991 The Influence of Testosterone on Human Aggression. British Journal of Psychology 82:1–28.Google Scholar
- Bell, G. H., D. Emslie-Smith, and C. R. Patterson 1980 Textbook of Physiology. Longmans: New York.Google Scholar
- Furlow, B. F., S. W. Gangestad, and T. Armijo-Prewitt 1997 Developmental Stability and Human Violence. Ms. Department of Biology, University of New Mexico, Albuquerque, in preparation.Google Scholar
- Gangestad, S.W., and R. Thornhill 1997 The Evolutionary Psychology of Extra-Pair Sex: The Role of Fluctuating Asymmetry. Evolution and Human Behavior, in press.Google Scholar
- Ingelby, H. 1949 Changes in Breast Volume in a Group of Normal Young Women. Bulletin of International Association of Medical Museums 29:87–92.Google Scholar
- Manning, J. T., D. Scutt, G. H. Whitehouse, S. J. Leinster, and V. Brown 1997 Cyclical Asymmetry: Its Homeostasis in Humans. Ms. School of Biological Sciences, University of Liverpool, in preparation.Google Scholar
- Meyer-Bahlburg, H. F. L., D. A. Boon, M. Sharma, and J. A. Edwards 1974 Aggressiveness and Testosterone Measures in Man. Psychosomatic Medicine 36:269–274.Google Scholar
- Monti, P. M., W. A. Brown, and D. D. Corriveau 1977 Testosterone and Components of Aggressive and Sexual Behavior in Man. American Journal of Psychiatry 134:692–694.Google Scholar
- Olweus, D., A. Mattsson, D. Scalling, and H. Low 1980 Testosterone, Aggression, Physical and Personality Dimensions in Normal Adolescent Males. Psychsomatic Medicine 42:253–269.Google Scholar
- 1992 Fluctuating Asymmetry as a Measure of Developmental Stability: Implications of Non-Normal Distributions and Power of Statistical Tests. Acta Zoologica Fennica 191:57–72.Google Scholar
- Parsons, P. A. 1992 Fluctuating Asymmetry: A Biological Monitor of Environmental and Genomic Stress. Heredity 68:361–364.Google Scholar
- Raine, A. 1993 The Psychopathology of Crime. San Diego: Academic Press.Google Scholar
- Scutt, D., and J. T. Manning 1996 Symmetry and Ovulation. Human Reproduction 11:2477–2480.Google Scholar
- Turek, F. W., and E. V. Cauter 1994 Rhythms in Reproduction. In The Physiology of Reproduction, E. Knobil, J. D. Neill, G. S. Greenwald, C. L. Markert, and D. W. Pfaff, eds. Pp. 487–540. Nottingham: Raven Press.Google Scholar
- Zar, J. H. 1984 Biostatistical Analysis. Prentice-Hall: New Jersey.Google Scholar