Using the term ecological validity, in a recent issue of Ecological Psychology, Rogers, Kadar, and Costall (2005) Rogers, S. , Kadar, E. and Costall, A. 2005. Gaze patterns in the visual control of straight-road driving and braking as a function of speed and expertise. Ecological Psychology, 17: 19–38. [Taylor & Francis Online], [Web of Science ®] [Google Scholar] discussed how the simulator they used could provide data by replicating natural road driving behaviors. However, ecological validity, as Brunswik (1956) Brunswik, E. 1956. Perception and the representative design of psychological experiments, , 2nd ed. Berkeley, CA: University of California Press.. [Google Scholar] conceived it, refers to the validity of a cue (i.e., perceptual variable) in predicting a criterion state of the environment. Like other psychologists in the past, Rogers et al. (2005) Rogers, S. , Kadar, E. and Costall, A. 2005. Gaze patterns in the visual control of straight-road driving and braking as a function of speed and expertise. Ecological Psychology, 17: 19–38. [Taylor & Francis Online], [Web of Science ®] [Google Scholar] confused this term with another of Brunswik's terms: representative design. In this comment, the authors clarify the distinction between these concepts and also discuss how Gibsonian ideas can strengthen understanding of the correspondence between experimental task constraints and behavioral settings outside the laboratory. The main implication of this theoretical rationalization is for the development of a measurable correspondence between experimental and behavioral contexts, enabling defensible generalization to both organisms and environments beyond the bounds of particular experiments.

Previous work on dynamics of interpersonal interactions in 1 vs. 1 sub-phases of basketball has identified changes in interpersonal distance between an attacker and defender as a potential control parameter for influencing organizational states of attacker–defender dyads. Other studies have reported the constraining effect of relative velocity between an attacker and defender in 1 vs. 1 dyads. To evaluate the relationship between these candidate control parameters, we compared the impact of both interpersonal distance and relative velocity on the pattern-forming dynamics of attacker–defender dyads in the sport of rugby union. Results revealed that when interpersonal distance achieved a critical value of less than 4 m, and relative velocity values increased or were maintained above 1 m · s⁻¹, a successful outcome (i.e. clean attempt) for an attacker was predicted. Alternatively, when values of relative velocity suddenly decreased below this threshold, at the same critical value of interpersonal distance, a successful outcome for the defender was predicted. Data demonstrated how the coupling of these two potential, nested control parameters moved the dyadic system to phase transitions, characterized as a try or a tackle. Observations suggested that relative velocity increased its influence on the organization of attacker–defender dyads in rugby union over time as spatial proximity to the try line increased.

This paper focuses on the paradoxical relationship between game unpredictability and the certainty of players' actions in team ball sports. Our research on this relationship leads us to suggest a method for training decision making, which we exemplify in the team sport of Rugby Union. The training methodology is based on application of theoretical insights from Ecological Psychology Complex Dynamical Systems and the Constraints-Led Approach. The paper starts with a critical overview of traditional approaches to studying decision making in sport. Next we describe the sport of Rugby Union to exemplify a complex dynamical system, and explain how that conceptualisation captures the interactions of players within that performance context. We conclude our analysis by describing how to manipulate task constraints to improve decision-making performance, as players search for an appropriate blend of stability and variability in their actions. In the final part of the paper, we suggest some methods to train decision making based on four stages: I) identifying the problem; ii) setting out a strategy to solve it; iii) creating an action model; and iv) building a decision-making exercise. The main conclusion from our work for coaches and sports scientists is that decision making should be improved through training methods that provide an accurate balance between stability of actions, which gives structure to the players' performance, and variability which allows them to cope with the uncertainty of situational constraints, such as the behaviour of specific opponents

Ecological dynamics characterizes adaptive behavior as an emergent, self-organizing property of interpersonal interactions in complex social systems. The authors conceptualize and investigate constraints on dynamics of decisions and actions in the multiagent system of team sports. They studied coadaptive interpersonal dynamics in rugby union to model potential control parameter and collective variable relations in attacker–defender dyads. A videogrammetry analysis revealed how some agents generated fluctuations by adapting displacement velocity to create phase transitions and destabilize dyadic subsystems near the try line. Agent interpersonal dynamics exhibited characteristics of chaotic attractors and informational constraints of rugby union boxed dyadic systems into a low dimensional attractor. Data suggests that decisions and actions of agents in sports teams may be characterized as emergent, self-organizing properties, governed by laws of dynamical systems at the ecological scale. Further re...