Some Cautionary Notes on Making Inferences about Relative Brain Size

  • Leonard Radinsky


The purpose of this paper is to call attention to some of the assumptions that are involved in analyzing and interpreting evolution of relative brain size. These assumptions are well known to the few people who generate and analyze primary data in this area, but may not be apparent to the larger audience that reads and repeats their conclusions. The assumptions I wish to consider are those involved in (1) estimating body weights of fossil species, (2) comparing relative brain sizes of different taxa or of different groups of taxa, and (3) attributing biological significance to differences in brain size.


Brain Size Fossil Species Tooth Size Skull Length Modern Species 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Anthony, R., 1938. Essai de recherche d’une expression anatomique approximative du degré d’organisation cérébrale autre que le poids de l’encéphale comparée au poids du corps. Bull. Soc. Anthropol. (Paris), 9(ser. 8):17–67.CrossRefGoogle Scholar
  2. Bauchot, R., and Stephan, H., 1966, Données nouvelles sur l’encéphalisation des insectivores et des prosimiens. Mammalia, 30:160–196.CrossRefGoogle Scholar
  3. Bauchot, R., and Stephan, H., 1969, Encéphalisation et niveau évolutif chez les simiens. Mammalia, 33:225–275.CrossRefGoogle Scholar
  4. Clutton-Brock, T.H., and Harvey, P., 1980, Primates, brains and ecology. J. Zool. London, 190:309–323.CrossRefGoogle Scholar
  5. Ehrlich, A., Fobes, J.L., and King, J.E., 1976, Prosimian learning capacities. J. Human Evol., 5:599–617.CrossRefGoogle Scholar
  6. Eisenberg, J.F., and Wilson, D.E, 1978, Relative brain size and feeding strategies in the Chiroptera. Evol., 32:740–751.CrossRefGoogle Scholar
  7. Gingerich, P.D., 1977, Correlation of tooth size and body size in living hominoid primates, with a note on relative brain size in Aegyptopithecus and Proconsul. Am. J. Phys. Anthrop, 47:395–398.CrossRefGoogle Scholar
  8. Glickman, S.E., and Sroges, R.W., 1966, Curiosity in zoo animals. Behaviour, 26:151–188.CrossRefGoogle Scholar
  9. Gould, S.J., 1975. Allometry in primates, with emphasis on scaling and the evolution of the brain. In, Approaches to Primate Paleobiology Contrib. Primat., Vol. 5, F. Szalay, ed., Karger, Basel, pp. 244–292.Google Scholar
  10. Hemmer, H., 1971, Beitrag zur Erfassung der progressiven Cephalisation bei Primaten. Proc. 3rd Int. Congr. Primat., Zurich 1970, 1:99–107.Google Scholar
  11. Jerison, H.J., 1973. Evolution of the Brain and Intelligence. Academic Press, N.Y, 482 pp.Google Scholar
  12. Jerison, H.J., 1979, Brain, body and encephalization in early primates. J. Human Evol., 8:615–635.CrossRefGoogle Scholar
  13. Krompecher, S., and Lipak, J., 1966, A simple method for determining cerebralization. J. Comp. Neurol., 127:113–120.CrossRefGoogle Scholar
  14. Le Gros Clark, W.E., 1971. The Antecedents of Man, 3rd. ed., Quadrangle Books, Chicago.Google Scholar
  15. Leutenegger, W., 1973, Encephalization in australopithecines: a new estimate. Folia Primat., 19:9–17.CrossRefGoogle Scholar
  16. Martin, R.D., 1973, Comparative anatomy and primate systematics. Symp. Zool. Soc. Lond, 33:301–337.Google Scholar
  17. Passingham, R.E., 1975, The brain and intelligence. Brain, Behav. Evol., 11:1–15.CrossRefGoogle Scholar
  18. Pilbeam, D., and Gould, S.J., 1974, Size and scaling in human evolution. Science, 186:892–901.CrossRefGoogle Scholar
  19. Pirlot, P., and Stephan, H., 1970, Encephalization in Chiroptera. Canadian J. Zool., 48:433–444.CrossRefGoogle Scholar
  20. Radinsky, L., 1967, Relative brain size: a new measure. Science, 155:836–838.CrossRefGoogle Scholar
  21. Radinsky, L., 1977, Early primate brains: facts and fiction. J. Human Evol., 6:79–86.CrossRefGoogle Scholar
  22. Radinsky, L., 1978, Evolution of brain size in carnivores and ungulates. Am. Natur., 112:815–831.CrossRefGoogle Scholar
  23. Riddell, W.I., and Corl, K.G., 1977, Comparative investigation of the relationship between cerebral indices and learning abilities. Brain, Behav. Evol., 14:385–398.CrossRefGoogle Scholar
  24. Sacher, G., 1975. Maturation and longevity in relation to cranial capacity in hominid evolution. In, Primate Functional Morphology and Evolution, R. Tuttle, ed., Mouton, The Hague, pp. 417–441.Google Scholar
  25. Slotnick, B.M. and Katz, H.M., 1974, Olfactory learning-set formation in rats. Science, 185:796–798.CrossRefGoogle Scholar
  26. Warren, J.M., 1973. Learning in vertebrates, pp. 471–509, In, Comparative Psychology, D.A. Dewsbury, and D.A. Rethlingshafer, eds., McGraw-Hill, New York.Google Scholar
  27. Warren, J.M., 1974, Possibly unique characteristics of learning by primates. J. Human Evol., 3:445–454.CrossRefGoogle Scholar
  28. Wilson, R.W., and Szalay, F.S., 1972, New paromomyid primate from middle Paleocene beds, Kutz Canyon area, San Juan Basin, New Mexico. Am. Mus. Novitates, 2499:1–18.Google Scholar

Copyright information

© Plenum Press, New York 1982

Authors and Affiliations

  • Leonard Radinsky
    • 1
  1. 1.Department of AnatomyUniversity of ChicagoChicagoUSA

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