Neural reuse posits development of functional overlap in brain system circuits to accommodate complex evolutionary functions. Evolutionary adaptation evolved neural circuits that have been exploited for many uses. One such use is engaging cognitive processes in memory consolidation during the neurobiological states of sleep. Neural reuse, therefore, should not be limited to neural circuitry, but be extended to include sleep-state associated memory processes.

Palmer demarcates the bounds of our understanding of color experience by symmetries in the color space. He claims that if there are symmetries, there can be functionally undetectable color transformations. However, even if there are symmetries, Palmer's support for the possibility of undetectable transformations assumes phenomenal internalism. Alternatively, phenomenal externalism eliminates Palmer's limit on our understanding of color experience.

The target article develops a computational connectionist model for analogy-making from a developmental perspective and evaluates this model using simple analogies. Our commentary critically reviews the advantages and limits of this approach, in particular with respect to its expressive power, its capability to generalize across analogous structure and analyze systematicity in analogies.

Cognitive agents are dynamical systems but not quantitative dynamical systems. Quantitative systems are forms of analogue computation, which is physically too unreliable as a basis for cognition. Instead, cognitive agents are dynamical systems that implement discrete forms of computation. Only such a synthesis of discrete computation and dynamical systems can provide the mathematical basis for modeling cognitive behavior.

Although the authors do a valuable service by elucidating the pitfalls of inferring top-down effects, they overreach by claiming that vision is cognitively impenetrable. Their argument, and the entire question of cognitive penetrability, seems rooted in a discrete, stage-like model of the mind that is unsupported by neural data.

Byrne & Russon's notion of program-level imitation is based on the ability of apes to plan novel sequences of behavior and on how information gleaned by observation can aid the planning process. Byrne & Russon would have made a stronger case by focusing on social learning and planning and expending less effort interpreting their results as a new category of imitation.

If embodied models no longer address the symbol grounding problem and a “disembodied” conceptual system can step in and resolve categorizations when embodied simulations fail, then perhaps the next step in theory-building is to isolate the unique contributions of embodied simulation. What is a disembodied conceptual system incapable of doing with respect to semantic processing or the categorization of smiles?