Hand preference and I.Q. in a group of Oxfordshire villages

Verbal and performance scores in a standard intelligence test (WAIS) were considered in relation to patterns of hand preference (measured by questionnaire) in a large sample of the general population. Left-handers and mixed-handers did not obtain lower scores than right-handers. Indeed, there was a tendency for subjects who reported that they could use either hand for at least one of the questionnaire tasks to obtain higher I.Q.s. Otherwise, there were no significant differences in I.Q. with the exception of a consistent sex difference, in that men achieved higher scores on both verbal and performance scales.