abstract
- The probe technique has been employed extensively to measure the attention demands of movement control. Inherent in any RT paradigm is the potential confounding effect of anticipation. Experiment 1 studied this problem by varying probe frequency (or, conversely, catch-trial frequency) for three independent groups of subjects performing the same movement. Probe frequencies of one-third and two-thirds produced V-shaped curves of probe RT plotted against probe position within the movement, while a three-thirds condition was described by a negatively sloped linear function. Because of the different shaped curves it was recommended that a two-thirds frequency be adopted by all researchers in this area. Experiments 2 and 3 looked at the effects of movement length and movement time on the attention demands of movement. Shorter (11-cm) movements were more attention demanding in the middle of the movement than the longer (50-cm) movements, but movement time had no effect.