Complexity matching—converging temporal correlations measured by correlating the slopes of power spectra—is a new measure of coordination based on information exchange between complex networks. To date, studies have focused on the dyadic case, but complexity matching may generalize to interacting complex networks in the left and right hemispheres of a single brain. We examined complexity matching in a perceptual-motor task between individuals and dyads. Participants alternated hitting targets in a Fitts-like task with the left and right hands of one individual, or analogously between two people. Response coupling was manipulated by making targets drift randomly (decoupled) or contingently (coupled). Results showed long-range correlations in time series of inter-response intervals exhibited complexity matching for both individuals and dyads, but only when responses were coupled via contingent drift. We conclude that complexity matching observed between individuals can similarly occur within one individual, suggesting a general principle of interaction at work.

Intelligent agents coordinate and cooperate flexibly when rules and dynamics of interaction can change over time and across different tasks and environmental conditions. Loose coupling emerges among agents when the rules of interaction are weak enough for agents to act independently or interdependently, and patterns of interaction vary as a function of conditions. Here, we examine collective foraging among simulated agents with and without human intervention. We find that loose coupling among search agents improved group foraging success, and that human players improved performance partly by subtle, indirect effects on group interactions. Analyses of movement patterns showed that loose coupling enabled collections of agents to self-organize and reorganize into a greater diversity of ad hoc groupings.

We examined the effects of individual versus joint action and racial similarity and dissimilarity on a Simon task using mouse tracking to explore the implicit cognitive dynamics underlying responses. Participants were slower to respond when working with a partner than when working alone, and their mouse movements also differed across conditions. Participants paired with a different-race partner took longer to respond than participants paired with a same-race partner. We argue that, in the joint conditions, participants’ longer responses were the result of automatic inhibitory processes that arise within the social context.

We examined the effects of individual versus joint action on aSimon task using motion tracking to explore the implicitcognitive dynamics underlying responses. In both individual andjoint conditions, participants were slower to respond, and weredifferentially attracted to the distracter response location, whenthe spatial component of the stimulus was incompatible with theresponse location. When two people completed similar twochoice tasks together, the results were not statistically differentfrom the individual condition, even though the magnitude of thestimulus-response compatibility effect was slightly larger.Neither was there an increased effect when the partner had nostimulus-response conflict to resolve. We found no evidence foran action conflict when the responses of the two partners weredifferent. These data imply that the literature regarding the JointSimon task is still in the process of determining the relevantevents that interact with and support joint action.