THE GEOMETRIC STRUCTURE, CONSTRUCTION, AND INTERPRETATION OF PATH-FOLLOWING (TRAIL-MAKING) TESTS

Diagnostic comparisons of performance on parts A and B of the Trail Ma king Test (TMT) assume that path structure in the two parts is equival ent but that task complexity is greater for B. The two parts are shown to differ with respect to length and angular variability. However, me asures of fractal dimension show no difference in structural complexit y between paths A and B. This analysis suggests a principled method fo r generating alternative pathways, varying in complexity, and opens th e way for a systematic study of path-following. It also suggests that path-following may be interpretable within a general approach, in whic h perceptual, linguistic, reasoning and motor processes are seen as re lated through different groups of geometric transformations. (C) 1996 John Wiley & Sons, Inc.