Correlations among handedness, eyedness, monocular shifts from binocular focal point, and nonverbal intelligence in university mathematics students.

Relationships among hand preference, nonverbal intelligence, and the monocular shifts of binocular focal point were studied in 33 men and 12 women university mathematics students. Ocular dominance was assessed with the Miles test. The monocular shift of binocular focal point for each eye was assessed with a modified Miles test. Hand preference was assessed on the Edinburg Handedness Inventory. Nonverbal intelligence was assessed with Cattell's Culture Fair Intelligence Test. In a prior study, the percentage of left-eye preference had been reported to be greater for mathematics students than for nonmathematics students. In the present study there were positive correlations between hand preference and the sum of the monocular shifts of two eyes. In addition, there was a negative correlation between nonverbal intelligence and the sum of the monocular shifts of two eyes. As these resultssuggest that the sum of the monocular shifts of two eyes may be related to mathematical ability and nonverbal intelligence, further research with a larger sample including non-mathematics students is needed.