Individual and collective foraging in autonomous search agents with human intervention.

Humans and other complex organisms exhibit intelligent behaviors as individual agents and as groups of coordinated agents. They can switch between independent and collective modes of behavior, and flexible switching can be advantageous for adapting to ongoing changes in conditions. In the present study, we investigated the flexibility between independent and collective modes of behavior in a simulated social foraging task designed to benefit from both modes: distancing among ten foraging agents promoted faster detection of resources, whereas flocking promoted faster consumption. There was a tradeoff between faster detection versus faster consumption, but both factors contributed to foraging success. Results showed that group foraging performance among simulated agents was enhanced by loose coupling that balanced distancing and flocking among agents and enabled them to fluidly switch among a variety of groupings. We also examined the effects of more sophisticated cognitive capacities by studying how human players improve performance when they control one of the search agents. Results showed that human intervention further enhanced group performance with loosely coupled agents, and human foragers performed better when coordinating with loosely coupled agents. Humans players adapted their balance of independent versus collective search modes in response to the dynamics of simulated agents, thereby demonstrating the importance of adaptive flexibility in social foraging.

Complexity matching and coordination in individual and dyadic performance.

Complexity matching is a measure of coordination based on information exchange between complex networks. To date, studies have focused mainly on interpersonal coordination, but complexity matching may generalize to interacting networks within individuals. The present study examined complexity matching in a double, coordinated Fitts' perceptual-motor task with comparable individual and dyadic conditions. Participants alternated touching targets with their left and right hands in the individual condition, or analogously with the left hand of one partner and the right hand of another in the dyadic condition. In Experiment 1, response coupling was manipulated by making targets drift either randomly or contingently based on prior responses. Here, drift refers to the variability in the target movements between response locations. Long-range correlations in time series of inter-response intervals exhibited complexity matching between the left and right hands of dyads and individuals. Response coupling was necessary for complexity matching in dyads but not individuals. When response coupling was absent in the dyadic condition, the degree of complexity matching was significantly reduced. Experiment 2 showed that the effect of coupling was due to interactions between left and right responses. Results also showed a weak, negative relationship between complexity matching and performance as measured by total response time. In conclusion, principles and measures of complexity matching apply similarly within and between individuals, and perceptual-motor performance can be facilitated by loose response coupling.

Perceiving nested affordances for another person's actions.

Affordances are available behaviors that emerge out of relations between properties of animals and properties of their environment. Affordances are nested within one another. One way to conceptualize this nesting is through a mean-ends hierarchy. Previous research has shown that perceivers are sensitive to hierarchical means-ends relationships when perceiving affordances for their own actions. Affordances are also nested in a social context. We investigated perception of hierarchical mean-ends nesting of affordances for another person's actions. We asked participants to judge the maximum reaching height of another person (the "actor"). Judgments of the actor's maximum reaching height reflected manipulated constraints on the reaching task, suggesting that participants were sensitive (prospectively) to hierarchical relations between lower order affordances and higher order affordances. In addition, the results revealed that judgments scaled to the reaching ability of the actor and not that of the perceiver. We argue that perceivers were sensitive to hierarchical means-ends nesting of affordances for another person across two-levels of this hierarchy, and that perceivers' judgments were based upon perceptual information about the actor's action capabilities, rather than being based upon simulation of perceivers' own abilities.

Multi-Scale Contingencies During Individual and Joint Action.

The present paper describes a joint action paradigm in which individuals or pairs utilized two computer keys to keep a dot stimulus moving inside a larger rectangle. Members of a pair could neither see nor hear each other. This paradigm allowed us to combine the discrete-trial type dependent variables (e.g., reaction time) commonly utilized by representational theorists, with the continuous, temporal dependence variables (e.g., RQA) utilized by dynamical theorists. Analysis revealed that individuals kept the dot in the rectangle longer than dyads and did so by moving it back and forth within the rectangle. Dyads, however, pressed their individual buttons as quickly as possible in order to keep the dot near the middle of the rectangle. These findings indicate that joint action constitutes a multi-scale phenomena that is best investigated via multiple, complementary methodologies versus single-measure, competing theories.