Sequence aiming movement between nervous systems

In two target aiming sequences, movement times to the first target are typically longer compared to single target responses – something referred to as the one-target advantage (OTA). Recent evidence has shown this advantage unfolds both within and between limbs, suggesting it emanates from a central representation. In a separate line of evidence, the involuntary movement interference or facilitation invoked by the concurrent observation of another moving agent has supported the view of a correspondence between perception and action. The following study explores the potential of the OTA unfolding between, as well as within, nervous systems. Thus, we had participants execute a fast-and-accurate aim to a single target (1T), two targets with one limb (2T1L), two targets with two limbs (2T2L), and two targets between two persons (2T2P). Movement time within the first segment revealed a significant effect of target sequence, which surprisingly indicated a significantly shorter time for the 2T2P condition compared to all other one- and two-target movements (Tukey HSD; ps <.05). On the contrary, it seems sequential movements between nervous systems does not reflect a correspondence with the information processes found during a single person context. Instead, there is complementary arrangement where the first person allocates more time for the second person to complete the movement. These findings present a novel joint action paradigm that potentially extends our understanding of perception-action frameworks.