Five tests of hand skill.

Four group tests of hand skill, square marking (SQUARES), dotting between targets (DOTS), line drawing between targets (LINES) and punching holes through targets (HOLES), were given to samples of undergraduates and schoolchildren, most of whom were also tested individually on a peg moving task (PEGS). Findings for PEGS were shown to be comparable to those of previous samples. Each new task was compared with PEGS for a standard measure of hand skill asymmetry (R-L%) using 4 criteria of comparison. For 3 criteria there was good agreement: correlations were statistically significant, hand preference subgroups were similar for rank order and the extent of asymmetry was more strongly associated with left hand scores than with right hand scores. This last finding was true for all of 12 comparisons for differing tests and samples, indicating that the finding is unlikely to be an artefact of score transformations as suggested by Bishop (1990a, 1990b). The fourth criterion of comparison, the distribution of R-L% scores, differed between the tasks. All of the new tasks found larger differences between the hands than PEGS. Whereas the shape of the distribution was unimodal for PEGS, as in previous studies, the distributions for DOTS and HOLES were clearly bimodal. Possible reasons for the larger between hand differences for some tasks are considered. It is suggested that the main difference between PEGS (and also to a lesser extent LINES) in comparison with DOTS and HOLES lies in the demand characteristics of the testing situation. Tasks which merely invite subjects to mark as many targets as possible in a unit of time may underestimate the skill of the nonpreferred hand.