Fig. 2.

Joint improvised motion by experts is more synchronized and rapid than leader–follower motion. (A) Two measures of synchronicity of the motions of the two players. The velocity traces are segmented to periods between zero-velocity events. For each segment, the relative velocity error (dV) and the timing difference between zero-velocity events (dT) are computed. (B) Relative velocity error between players, dV, averaged over all segments. (C) Mean temporal differences between zero-velocity events of the two players, dT, averaged over all segments. (D) Maximal velocity averaged over all segments. (E) Relative velocity error in all segments, as a function of average segment velocity. Brown and green dots correspond to LF and JI rounds, respectively. Areas 1 and 2 are regions reached primarily in JI rounds and not in LF rounds. (F) Relative velocity error as a function of velocity. Shown is median dV in equal-sized velocity bins, with SEs computed by bootstrapping (*P < 0.01, **P < 0.001).