Husband-Wife Correlations in Neurocognitive Test Performance

Spousal correlations are known to have a number of physical and mental characteristics, among which general mental ability is one of the strongest. IQ tests have ordinarily been used in studies of assortative mating, but in neurocognitive tests, less frequently. In this study, we examined spousal correlations in 76 husband-wife pairs using a computerized neuropsychological test battery. Significant spousal correlations occurred in the two most highly g-loaded tests, shifting attention and symbol digit coding, but not in the other tests or in any of the reaction time measures. The correlation between husbands and wives on the neurocognitive index, a summary score based on the individual tests and analogous to the IQ score, was even higher (r = .717). The pattern of spousal correlation described in IQ tests is thus replicated in a battery of neuropsychological tests. In a previous paper we reported positive correlations between first-degree relatives who were administered the CNT battery, and which occurred primarily in tests of complex information processing, SDC and SAT (Hervey, Greenfield, & Gualtieri, 2012). In this paper, we note that the same two tests contribute more strongly than any other tests to the high spousal correlation for neurocognition. There is a certain symmetry, then, between the cognitive skills that play into spouse selection and the cognitive skills that are inherited. A better word than symmetry might be inevitability. The findings of these studies suggest that computerized neurocognitive testing is an appropriate tool for studies of the genetics of cognition, that measures of processing speed are particularly salient and that the CNT is a suitable instrument. The advantages of computerized neurocognitive tests like the CNT include speed and efficiency, standard administration, suitability for repeated measures and elimination of scoring and transcription errors. Tests that are Internet-based like the CNT are amenable to centralized data collection and have flexibility in administration in different settings, even permitting the collection of data from remote sources. In genetic studies of cognition, where large numbers of subjects are necessary, this technology may also be inevitable.