The use of next-of-kin in assessing handedness.

The present study administered a 15-item handedness questionnaire to 129 college students and their next-of-kin. This questionnaire was similar to the Edinburgh Handedness Inventory, except that a 7-point scale was used instead of a 2-choice scale. Test-retest reliability was evaluated with a second administration of the handedness questionnaire to each subject. Analysis showed a high test-retest reliability for all items and a high correlation between subjects and next-of-kin responding for most items. However, some items on the Edinburgh Handedness Inventory showed much higher correlations than others when comparing subject and next-of-kin responding. The contribution of these data is that subjects' handedness can be accurately estimated from next-of-kin responses if a subset of these questionnaire items are used.