Understanding social motor coordination

Recently there has been much interest in social coordination of motor movements, or as it is referred to by some researchers, joint action. This paper reviews the cognitive perspective’s common coding/mirror neuron theory of joint action, describes some of its limitations and then presents the behavioral dynamics perspective as an alternative way of understanding social motor coordination. In particular, behavioral dynamics’ ability to explain the temporal coordination of interacting individuals is detailed. Two experiments are then described that demonstrate how dynamical processes of synchronization are apparent in the coordination underlying everyday joint actions such as martial art exercises, hand-clapping games, and conversations. The import of this evidence is that emergent dynamic patterns such as synchronization are the behavioral order that any neural substrate supporting joint action (e.g., mirror systems) would have to sustain.     

Collective rationality in interactive decisions: evidence for team reasoning

Decision theory and game theory rest on a fundamental assumption that players seek to maximize their individual utilities, but in some interactive decisions it seems intuitively reasonable to aim to maximize the utility of the group of players as a whole. Such team reasoning requires collective preferences and a distinctive mode of reasoning from preferences to decisions. Findings from two experiments provide evidence for collective preferences and team reasoning. In lifelike vignettes (Experiment 1) and abstract games (Experiment 2) with certain structural properties, most players preferred team-reasoning strategies to strategies supporting unique Nash equilibria, although individually rational players should choose equilibrium strategies. These findings suggest that team reasoning predicts strategy choices more powerfully than orthodox game theory in some games.     

Comparing the influence of directly vs. indirectly encountered post-event misinformation on eyewitness remembering

Some research has found a stronger influence of directly (face-to-face; co-witness; ‘social’) vs. indirectly (through written reports, ‘non-social’) encountered post-event misinformation on eyewitness memory reports, whereas other research finds no (big) difference. We argue and demonstrate that a crucial but so far neglected variable underlying this difference is memory for the misleading information itself. In a study with N = 120 participants who encountered misinformation directly or indirectly, we found misinformation retention (as assessed in a separate test) to be positively associated with a broad range of misinformation effects. Influence type (direct vs. indirect), however, did not moderate the misinformation effect in terms of memory for original details, and misinformation endorsement was even weaker in the direct influence condition. In our view, these findings reflect differential conversion of retained misinformation into test performance. Other than this, influence type had essentially no effects on remembering; nor did an additional post-warning manipulation.     

Methodological individualism in experimental games: not so easily dismissed

Orthodox game theory and social preference models cannot explain why people cooperate in many experimental games or how they manage to coordinate their choices. The theory of evidential decision making provides a solution, based on the idea that people tend to project their own choices onto others, whatever these choices might be. Evidential decision making preserves methodological individualism, and it works without recourse to social preferences. Rejecting methodological individualism, team reasoning is a thinly disguised resurgence of the group mind fallacy, and the experiments reported by Colman et al. [Colman, A. M., Pulford, B. D., & Rose, J. (this issue). Collective rationality in interactive decisions: Evidence for team reasoning. Acta Psychologica, doi:10.1016/j.actpsy.2007.08.003.] do not offer evidence that uniquely supports team reasoning.     

Sensitivity to social contingency or stability of interaction? Modelling the dynamics of perceptual crossing

We introduce a series of evolutionary robotics simulations that address the behaviour of individuals in socially contingent interactions. The models are based on a recent study by Auvray, Lenay and Stewart [(2006). The attribution of intentionality in a simulated environment: The case of minimalist devices. In Tenth meeting of the association for the scientific study of consciousness, Oxford, UK, 23-26 June, 2006] on tactile perceptual crossing in a minimal virtual environment. In accordance, both the empirical experiments and our simulations point out the essential character of global embodied interaction dynamics for the sensitivity to contingency to arise. Rather than being individually perceived by any of the interactors, sensitivity to contingency arises from processes of circular causality that characterise the collective dynamics. Such global dynamical aspects are frequently neglected when studying social cognition. Furthermore, our synthetic studies point out interesting aspects of the task that are not immediately obvious in the empirical data. They, in addition, generate new hypotheses for further experiments. We conclude by promoting a minimal but tractable, dynamic and embodied account to social interaction, combining synthetic and empirical findings as well as concrete predictions regarding sensorimotor strategies, the role of time-delays and robustness to perturbations in interactive dynamics.     

“Imaginative research” on Persuasion: Subverting apparent certainty

In this paper it is my intention to contribute to the Discursive approach to one of the most popular topics in Social Psychology: Persuasion. On the one hand, during the last five or six decades there has been great interest by Cognitive Psychologists on the matter of constructing explicative models that would explain, in their own terms, how persuasive communication works and which variables might be at stake. On the other hand, Discursive Psychologists (see for instance [Billig, 1987] and [Shi-xu, 2006]) have continually criticized cognitive and mentalist notions of Persuasion by arguing that Persuasion is actually an inherent and complex rhetorical component of all texts and talk, and ought to be thought of more as a linguistic skill than as a mental process. As Billig (1987) has cleverly stated, it is imaginative research that discovers recalcitrant situations that ultimately shatters the notions of scientific certainty. This paper undertakes to reexamine some of the most famous classical studies on Persuasion in order to emphasize the complexity of the rhetorical phenomena involved and to show the importance of providing alternative frames of analysis.     

Can dancers suppress the haptically mediated interpersonal entrainment during rhythmic sway?

Interpersonal entrainment emerges spontaneously when partners performing rhythmic movements together exchange sensory feedback about the other's movements. In this study, we asked whether couples of expert dancers, non-dancers and mixed couples can suppress the spontaneous haptically mediated inter-personal entrainment when their rhythmic sway is paced by differing metronome tempos. Fifty-four young participants formed three types of couples: nine dancer couples, consisting of individuals with at least eight years systematic practice in traditional Greek dance; nine non-dancer couples, consisting of individuals with no prior experience in dance and nine mixed couples, consisting of one dancer and one novice partner. Partners swayed rhythmically for 60 s, at different pacing frequencies (one at 0.25 Hz and the other at 0.35 Hz) under three haptic contact conditions: no contact between them; light fingertip touch established in the 2nd trial segment (30 s); and light fingertip touch released in the 2nd trial segment (30 s). Spectral analysis of the antero-posterior center of pressure displacement revealed that light touch increased the deviation of the dominant from the target (pacing) sway frequency, decreased the proportion of the signal's power at the target frequency and increased the coherence between the partners' sway signals (inter-personal coherence). These effects were specific to the mixed group whereas touch interference was weaker in non-dancers and absent in dancers. In addition, the coherence between the trial segments (intra-personal coherence) significantly decreased with touch only for the non-dancer while it remained unchanged for the dancer partner of the mixed group suggesting that the dancer was leading the non-dancer partner. It is concluded that systematic practice with traditional dance can modulate the spontaneous tendency towards haptically mediated interpersonal entrainment.     

Nash equilibrium, team reasoning and cognitive hierarchy theory

This paper comments on two experiments, carried out by Colman, Pulford and Rose, which investigate the prevalence of team reasoning. I argue that because the first experiment uses 'decomposable' games, it cannot discriminate between team-reasoning and the conceptually distinct 'prosocial' orientation. In the second experiment, Colman et al. find more support for the team reasoning hypothesis than for the rival hypothesis that subjects choose Nash equilibrium strategies. I suggest that the most credible explanation of the data is that some subjects are team reasoners while others act according to cognitive hierarchy theory.     

Collective rationality: the integrative model explains it (as) well

In this commentary, I argue that there is indeed considerable evidence in support of the notion that people tend to reason from a collective (or team) perspective by asking themselves questions such as "What do we want, and what should I do help achieve it?" [Colman, A. M., Pulford, B. D., & Rose, J. (2008). Collective rationality in interactive decisions: Evidence for team reasoning. Acta Psychologica]. As such, in my view, team reasoning -- and thinking, feeling, and acting in terms of collective rationality -- is consistent with a social utility model (or transformational model) which considers the weights that people attach not only to outcomes for self, but also to outcomes for other, and to equality in outcomes [Van Lange, P. A. M. (1999). The pursuit of joint outcomes and equality in outcomes: An integrative model of social value orientation. Journal of Personality and Social Psychology,77, 337-349]. This commentary provides an illustration demonstrating that the integrative model is well-suited to account for the findings observed by Colman et al. (2008).     

"With a little help from my friends...": the role of co-witness relationship in susceptibility to misinformation

Inaccuracies in eyewitness accounts can occur when witnesses are exposed to post-event misinformation via discussion with a co-witness. The current study examined the role of co-witness relationship by comparing the memory performance of pairs of romantic couples, friends and previously unacquainted strangers with that of individuals. Ninety-six participants viewed an event and then discussed the witnessed event with a stranger, a romantic partner or a friend. One member of each pair saw a theft take place during the witnessed event. Individual group participants did not discuss the witnessed event with anyone. Results indicate that all co-witness dyads produced less accurate recall accounts than participants who did not interact with another witness. However, witnesses who were previously acquainted with their co-witness (either in a friendship or romantic relationship) were significantly more likely to report information obtained from their co-witness that they had not seen themselves. Prior acquaintance also led to an increased number of incorrect attributions of both guilt and innocence.