To balance Kubovy & Epstein, I evaluate the relationship between Shepard and Gestalt theorists along three dimensions. First, both discover internal universals by reducing external support. Second, they share strengths and weaknesses of the minimum principle. Third, although their attitudes toward an evolutionary account of perception is superficially different, they are fundamentally similar with respect to the internalization process. [Kubovy & Epstein; Shepard]

From the perspective of biological cybernetics, “real world” robots have no fundamental advantage over computer simulations when used as models for biological behavior. They can even weaken biological relevance. From an engineering point of view, however, robots can benefit from solutions found in biological systems. We emphasize the importance of this distinction and give examples for artificial systems based on insect biology.

Hertwig and Ortmann suggest greater standardization of procedures in experimental psychology to help with problems of replicability and consistency of findings. It is argued that, (a) this view is inconsistent with their other interesting proposals, and (b) heterogeneity of method is appropriate in psychology.

Overwhelming evidence points to the existence of separate sensory channels in the nervous system. The power of this type of parallel organization is that information is first processed in neurons specialized to code it most efficiently. However, sensory pathways are convergent and divergent at each level as well, as is necessary to interpret multimodal and conflicting information.

How to conceive the place of the brain in the specification of the animal environment relation? Reality is a continuum between external physical energies and brain energy. The global array concept linked to the physical world and its physical energies could be transposed to the brain as a physical object and a dynamical system.

While robotics has benefited from inspiration gained from biology, the opposite is not the case: there are few if any cases in which robotic models have lead to genuine insight into biology. We analyze the reasons why biorobotics has been essentially a one-way street. We argue that the development of better tools is essential for progress in this field.

The target article suggests that many practices of experimental economists are preferable to those used by psychologists studying judgment and decision making. The advantages of the psychological approach become clear when the focus of research shifts from choice output to choice processes. I illustrate this point with an example from research on similarity comparisons.

Thelen et al. present a convincing explanation of the A-not-B error, but contrary to their own claims, their explanation essentially involves mental representations. As is too common among cognitive scientists, they equate mental representations with representations of external physical objects. They clearly show, however, that representations of bodily actions on physical objects are central to the dynamical system producing the error.

It is argued that color constancy is only one of the benefits of color vision and probably not the most important one. Attention to a different benefit, chromatic contrast, suggests that the features of the environment that played a role in the evolution of color vision are properties of particular ecological niches rather than properties of naturally-occurring illumination. [Shepard]

Perceptual learning mechanisms derived from Hebb's theory of cell assemblies can generate prototypic representations capable of extending the representational power of TEC (Theory of Event Coding) event codes. The extended capability includes categorization that accommodates “family resemblances” and problem solving that uses cognitive maps.

The epistemological premises and scientific viability of Stoffregen & Bardy's ecological perspective are evaluated by analyzing the concept of direct perception of global invariants vis-à-vis (1) behavioral evidence that perception is based on the integration of modal sources of information and (2) neurophysiological aspects of the integration of sensory signals.

The field theoretic approach of the target article is simplified by setting the parameters of the dynamical field equation so that the system is near the critical point between cooperative and non-cooperative dynamics. However, embodiment of cognitive development would require a closer connection between the dynamical field interactions and the physiology of the cerebral cortex.

In recent years, neurophysiological evidence has accumulated in favor of a common coding between perception and execution of action. We review findings from recent neuroimaging experiments in the action domain with three complementary perspectives: perception of action, covert action triggered by perception, and reproduction of perceived action (imitation). All studies point to the parietal cortex as a key region for body movement representation, both observed and performed.

To be plausible, biorobots will need to build themselves. Such autopoietic systems will be autonomous, active learners whose functional architecture is a joint product of factors supplied by the designer and factors learned from encountering an environment. Creating such biorobots will require appropriate theories of cognition, learning, and evolution, all of which are available.

Shepard provides an account of mechanisms underlying perceptual judgment or representation. Ought we to interpret the account as revealing principles on which those mechanisms operate or merely an account of principles to which their operation apparently conforms? The difference, invisible so long as we remain at a high level of abstraction, becomes important when we begin to consider implementation. [Shepard]

For a variety of reasons, including the common use of deception in psychology experiments, participants often disbelieve experimenters' assertions about important task parameters. This can lead researchers to conclude incorrectly that participants are behaving non- normatively. The problem can be overcome by deriving and testing normative models that do not assume full belief in key task parameters. A real experimental example is discussed.

Biology can inspire robotic simulations of behavior and thus advance robotics, but the validity of drawing conclusions about real behavior from robotic models is questionable. Robotic models, particularly of learning, do not account, for example, for (a) exaptation: co-opting of previously evolved functions for new behavior, (b) learning through observation, (c) complex biological reality, or (d) limits on computational capacity.

There is good neuropsychological evidence for an amodal, relational basis for perception and action. Using this idea, it may be possible to define more accurately what is meant by specificity, in the Gibsonian sense of the term. However, for complex organisms, and most especially for creative, open-ended perceivers and actors such as human beings, specification may not be relevant.

In this commentary, I raise several points. First, I argue that non-search tasks show that the A-not-B task is about object representation, even if perseveration can occur without objects. Second, I provide an alternative interpretation for the finding that changing body posture reduces A-not-B errors. Third, I provide an alternative interpretation for the finding of convergence in reaching behavior in two-target tasks. Fourth, I suggest attention deficits can explain the A-not-B error on their own with no necessity for motor memories.

The great advantage of Tenenbaum and Griffiths's model is that it incorporates both specific and general prior knowledge into category learning. Two phenomena are presented as supporting the detailed assumptions of this model. However, one phenomenon, effects of diversity, does not seem to require these assumptions, and the other phenomenon, effects of sample size, is not representative of most reported results. [Tenenbaum & Griffiths]