The K-factor: Individual differences in life history strategy

Aurelio José Figueredo, Geneva Vásquez, Barbara Hagenah Brumbach, Jon Adam Sefcek, Beth R. Kirsner, W. Jake Jacobs

Research output: Contribution to journalArticlepeer-review

280 Scopus citations


Until recently, variations in life history strategy were studied exclusively at the species level. Although this domain of study has been extended to examine systematic differences in life history strategy among various human ethnic groupings, more recent evolutionary theories of human development and related behavioral genetic work imply substantial within-group individual variation in life history strategy. We constructed a latent variable model identifying a single common factor, denoted as K, which underlies a variety of otherwise disparate life history parameters. This "K-Factor" loaded 0.36 on childhood attachment to the biological father, -0.36 on childhood attachment to any non-biological father figure, 0.38 on adult romantic partner attachment, -0.51 on mating effort, -0.58 on Machiavellianism, and -0.41 on risk propensity. The bivariate correlations of the K-factor with higher-order personality factors were statistically significant, -0.24 with "Big Neuroticism" and -0.67 with "Big Psychoticism", and approached significance, correlating 0.12, with "Big Extraversion". The K-factor appears to be an underappreciated individual difference variable of major importance to human development.

Original languageEnglish (US)
Pages (from-to)1349-1360
Number of pages12
JournalPersonality and Individual Differences
Issue number8
StatePublished - Dec 2005


  • Evolutionary psychology
  • Frequency-dependent selection
  • Life History Theory
  • Personality
  • Reproductive strategy

ASJC Scopus subject areas

  • General Psychology


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