Recent adaptationist accounts of human mental and physical health have reinvigorated the debate over the evolution of human intelligence. In the tradition of strong inference the current study was developed to determine which hypothesis; Rushton’s (2000) differential K theory, or Miller’s (2000a) fitness indicator model (F), better accounts for general intelligence ('g') in an undergraduate university population (N = 194). Due to the lengthy administration time of the test materials a newly developed 18-item short form of the Ravens Advanced Progressive Matrices (APM-18; Sefcek, Miller, & Figueredo, 2007) was used. There was a significant positive relationship between K and F (r = .31, p < .001), however no significant relationships were found between 'g' and either K or F (for each, r = -.06, p ≥ .05). While contrary to both hypotheses, these results may be explained in relation to antagonistic pleiotropy and a potential failure to derive within species comparisons directly from between species comparisons.