Right-left discrimination in male and female, young and old subjects.

The present study investigated right-left discrimination, with a paper-and-pen test using line figures. The test consists of line drawings of a person with no, one, or both arms crossing the vertical body axis of the figure. The subjects' task is to mark with a pencil, as fast as possible, which is the right or left hand in the figure. The line drawings are either viewed from the back, from the front, or randomly alternating between the back and front views. The sample consisted of 322 male and female subjects, split into four different groups, from children to old adults. The results showed increasing performance from children to young adults, with a decline in performance in the old adults (>50 years). The condition with alternating front-back views was the most difficult, particularly when the figure also had both arms crossing the vertical body midline. There were no gender differences except for better male performance in the young adults group (18-22 years). The results are discussed in relation to theories of mental rotation and lateralization of information processing strategies, in addition to right-left discrimination across the age groups.