Edinburgh Handedness Inventory scores: Caucasian and American Indian college students.

Laterality Quotients for 80 American Indian college students were less right-biased than those for 80 Caucasian college students on the Edinburgh Handedness Inventory. Oldfield's 1971 empirically derived deciles for the Edinburgh Handedness Inventory were used to assign decile levels to the data. Deciles were then used to assign data to one of three proposed handedness phenotype classifications. Phenotype classifications were based on Annett's 1985 proposed distribution for a single gene theorized to underlie human handedness. Chi-squared goodness-of-fit analysis showed that the data for Caucasian college students did not differ significantly from what would be anticipated by Annett's model, but American Indians differed significantly. Results provide empirical support for the hypothesis that frequency distributions for Annett's hypothesized right-shift gene may differ across racial groups.