Table 4.

Frequency of repeat and non-repeat trials compared to distributions expected by random movement choices. On average each game contained 67 trials that were categorized as repeats or non-repeats (movement trials preceded by blank were excluded from analysis). The mean number of trials in each group was compared to the expected number of trials when movements are random (where one would expect 22 repeat and 45 non-repeat trials for each of the trial types). A t-test was performed to determine whether the actual number of repeats/non-repeats differed from that expected, separately for each trial type. A small yet significant deviation from randomness was found in the observed-then-executed trial type where there were fewer repeats and more non-repeats than expected (suggesting that subjects actively avoided executing previously observed movements).

Trial Type	Mean # of Trials (Standard Error)	T value	P value
Observed Repeats	22 (0)	−0.52	0.61
Observed Non-Repeats	45 (0)	0.12	0.9
Executed Repeats	21.4 (2.4)	−1	0.32
Executed Non-Repeats	45.3 (2.4)	0.7	0.48
Observed-then-Executed Repeats	18.3 (1.8)	−5.75 *	< 0.001 *
Observed-then-Executed Non-Repeats	48.4 (1.8)	5.34 *	< 0.001 *
Executed-thenObserved Repeats	22.4 (1)	0.13	0.89
Executed-then-Observed Non-Repeats	44.3 (1)	−0.51	0.61