Because the social × force × time interaction effect was found to be highly significant ( F (15, 270) = 3.96, p < 0.0001), we subsequently performed separate two-way ANOVAs with two repeated factors (i.e., social condition and target force level) for each 1-s epoch.
Because of this difference in force error between the two tasks, the presence of an evaluative audience affected motor performance more robustly for the 10% MVC task: social condition × target force level interactions were significant for epochs 15, 14, 13, 10, and 9 ( F (1, 18) = 8.32, p = 0.010; F (1, 18) = 7.21, p = 0.015; F (1, 18) = 4.52, p = 0.048; F (1, 18) = 5.08, p = 0.037; F (1, 18) = 4.84, p = 0.041, respectively) and marginally significant for epochs 11 and 8 ( F (1, 18) = 3.73, p = 0.069; F (1, 18) = 3.67, p = 0.071, respectively).
For the 5% MVC task, the effect of audience on grip force showed greater individual differences, and did not reach statistical significance at the group level at any time point.