CONSTRUCT-VALIDITY IN THE TRAIL MAKING TEST - WHAT MAKES PART-B HARDER

The Trail Making Test (TMT) is primarily a test of motor speed and vis ual attention. In Trail Making, Part A, the subject's task is to quick ly draw lines on a page connecting 25 consecutive numbers. In Part B, the subject must draw the lines alternating between numbers and letter s. To determine what makes Part B harder than Part A, variations of th e standard Trail Making Test were assessed. Forty college students (20 male, 20 female) were given four forms of the Trail Making Test. The results show that Trail Making, Part B with just numbers took longer t o complete than the standard Part A with numbers. Part B is 56 cm long er and has more visually interfering stimuli than Part A. These result s indicate that Part B is more difficult than Part A not only because it is a more difficult cognitive task, but also because of its increas ed demands in motor speed and visual search.