Fig 1. For each subject, number of correct category sorts to each Fist (F) and Shoulder (S) sample.

Sorting under the look-at-sample instruction is shown by gray bars for subjects who completed all 18 test trials and by gray filled circles for subjects who failed to meet criterion in the first six trials. The performances of these latter subjects on the 18 trials under the tact-sample instruction are shown by the black bars.