I present my observations of combinatory manipulations by three infant chimpanzees in a series of test tasks. Common characteristics of motor patterns were observed across the tasks between both infant chimpanzees and 1-year-old infants. Based on the results, I point out that comparative approach can illuminate Thelen et al.'s arguments.

Any discussion comparing different models with respect to their quality qua models must presuppose a notion of model, that is, what it is to be a model. While Webb provides seven criteria to assess the quality of various proposed biorobotic models, she does not clarify the very notion of “model of animal behavior” itself.

Shepard's (1994) choice of kinematic geometry to support his theory is questioned by Todorovic, Schwartz, and Hecht. His theoretical framework, however, can be applied to another domain that may be less susceptible to some of their concerns. The domain is the representation of spatial layout. [Hecht; Schwartz; Shepard; Todorovič]

My main argument is that the advice offered to experimental psychologists by Hertwig & Ortmann overlooks fundamental differences between the goals of researchers in psychology and economics. Furthermore, it is argued that the reduction of data variability is not always an end to be sought by psychologists. Variability that originates in individual differences constitutes valuable data for psychological research.

Natural language processing involves a tight coupling between action (the production of language) and perception (the comprehension of language). We argue that similar theoretical principles apply to language processing as to action/perception in general. Language production is not driven solely by the speaker's intentions; language comprehension is not only input-driven; production and perception use common representations. We will relate recent findings from our language production lab to the Theory of Event Coding (TEC)'s principle of feature binding.

The global array might prove to be an important and even necessary concept for explaining some multi-modal phenomena from the specificational perspective. However, we suspect that specification exists in energy arrays detectable by single or multiple sensory systems. We argue for a more general modality-neutral perspective and review results from recent research on audiovisual speech perception.

We argue four points. First, perception always relies on environmental constraints, not only in special cases. Second, constraints are taken advantage of by detecting information granted by the constraints rather than by internalizing them. Third, apparent motion phenomena reveal reliance on constraints that are irrelevant in everyday perception. Fourth, constraints are selected through individual learning as well as evolution. The “perceptual-concept-of-velocity” phenomenon is featured as a relevant case. [Hecht; Kubovy & Epstein; Shepard]

Stoffregen & Bardy's proposal that perceptual systems can use information defined across two or more sensory domains is valuable and urgent in its own right. However, their claim of exclusive validity for global-array information is superfluous and perpetuated for incorrect reasons. The seeming ambiguities of individual arrays emanate from failures to consider relevant ecological constraints and higher-order variables.

The adoption of experimental methods from economics, in particular script-enactment, performance-related payment, and the absence of deception, will turn experimental social psychology into a trivial science subject. Such procedures force participants to conform to a normative expectation that they must behave rationally and in accordance with their self-interest. The self-fulfilling prophecy inherent in these procedures makes it more difficult to conduct innovative social-psychological research.

Thelen et al. offer an inspiring behavior-based theory of a long-standing cognitive problem. They demonstrate how joining traditions, old (the Gestaltist field theory) and new (dynamical systems theory) may open up the path towards embodied cognition. We discuss possible next steps. Self-organization theory (synergetics) could be used to address the formation of gaze/reach attractors and their optimality, given environmental control parameters. Finally, some clinical applications of the field model are advocated.

The Theory of Event Coding (TEC) is a significant contribution to the study of purposeful perceptual behavior, and can be made more so by recognizing a major context (the work of Tolman, Liberman, Neisser); some significant problems (tightening predictions and defining distal stimuli); and an extremely important area of potential application (ongoing anticipation and perceptual inquiry, as in reading and movies).

Biorobotics research should not only target “realistic” models of living systems and be judged exclusively from that perspective. It should pay just as much attention to formal models and artificial systems. They allow the examination of assumptions which do not necessarily hold for living systems, but precisely therein lies their value. They generate insight by enabling a comparison between the artificial and the real.

The target article's value lies not in its defence of specification, or the “global array” concept, but in its challenge to the paradigm of 5+ senses, and its examples of multiple receptor types cooperatively participating in specific pick-up tasks. Rather than analysing our perceptual endowment into 5+ senses, it is more revealing to type perceptual systems according to task.

Hecht provides insights concerning the difficulty of empirically testing Shepard's internalization hypothesis, but his argument for an externalization hypothesis suffers from similar sins. [Hecht]

Hommel et al. propose that action planning and perception utilize common resources. This implies perception should have intention-relative content. Data supporting this implication are presented. These findings challenge the notion of perception as “seeing.” An alternative is suggested (i.e., perception as distal control) that may provide a means of integrating representational and ecological approaches to the study of organism-environment coordination.

Reaching in the A-not-B situation is not the product of a single person, but rather of a person-person system. We argue that models of embodied cognition distributed over persons may be necessary to capture the essential qualities of evolving behaviors, even those as simple asperseverative reaching.

Three comments take issue with specifics of the target article. First, I argue for the development of meta-theory to deal with inconsistencies in experimental results. Second, I advocate the use of the compatibility between experiment and application to decide on the optimal design and procedure of experimental studies. Last, I support the explicit incorporation of motivation into models of decision making.

We support Webb's insights into the potential benefits of using robotic modeling to better understand biological behavior. We defend the major points put forward by Webb by presenting a specific case study in which robotic modeling of mobile ball catching has helped refine and clarify aspects of our understanding of biological interceptive behavior.

We discuss the assumptions put forward by Thelen et al. about motor planning processes. We examine the results of an experiment inspired by the authors' contention that the motor plans of both infants and adults are continuous and graded. We wondered whether adults, in an adapted version of the A-not-B error paradigm, would point between the A and B targets, as in some degraded conditions of pointing (Ghez et al. 1990), or would make A-not-B errors. Unexpectedly, we observed that adults tended to shift the direction of their pointings to B away from A, and did not make any A-not-B errors.

Hommel et al. emphasize that the Theory of Event Coding (TEC)'s utility is not its ability to be a new theory of cognition, but its ability to engender new thinking about new and old problems. In this commentary we use the TEC to re-examine a long-standing discrepancy in the attention literature.