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Norm-of-Reaction: Definition and misinterpretation of animal research
Journal of Comparative Psychology (1988)
  • Steve A. Platt, Northern Michigan University
  • Charles A. Sanislow, Duke University

The development of a phenotype is due to an interaction of the genotype with the environment. Two terms have been used to describe the outcome of this interaction, the norm-of-reaction and the reaction range. The first represents the theoretically limitless distribution of the phenotypes that may be expressed by a given genotype. The reaction range implies an upper and lower limit for phenotype expression possible from a given genotype. A critical distinction between the reaction range and the norm-of-reaction is that the norm-of-reaction is a statement of the conceivable interactions found but does not imply any predictability other than that within the conditions previously tested experimentally, that is, the tails of a normal distribution are infinitely variable, whereas the concept of reaction range implies a limitation inherent in the genotype, that is, a finite range. Empirical support for the reaction-range concept is questionable. Animal studies cited in support of the reaction range have been inappropriately and incorrectly interpreted.

  • Norm-of-Reaction,
  • Reaction Range,
  • Intelligence,
  • Race,
  • Genes
Publication Date
Citation Information
Platt, S. A. & Sanislow, C. A. (1988). Norm-of-Reaction: Definition and misinterpretation of animal research. Journal of Comparative Psychology, 102(3), 254-261.