Movement patterns in impaired gait are not selected by a smart central nervous system (CNS), but arise by virtue of mutual constraints of task, limitations in personal dynamics available for the task, and optimality criteria. An oscillatory model of gait cycle is presented that exemplifies this control and coordination scheme. Preferred gait patterns may be based on physical principles rather than CNS “coordinative rules.”

Houk et al. suggest that excitatory output from the cerebellar nuclei is fed back into the cerebellum, thus generating a prolonged activity in the cerebellar nuclei which is then molded by inhibitory Purkinje cells. Recent evidence, however, shows that a temporary break in this loop causes a pause in a conditioned eyeblink response, but does not terminate it. [HOUK et al.]

Although the target article is groundbreaking and creatively conceived, there are troubling questions regarding its methodology and conclusions. The sample in the authors' study was drawn from a popular magazine's lists; there is no recognition of the fact that most faculty are now off the tenure track; and comparisons are made with the British system with no supporting data.

The perceptual circularity demonstrated by R. Shepard with respect to hue turns out to be a sphericity of color perception based on color excitation vectors of neuronal level. The spherical color model implicitly contains information concerning generalization under color learning. Subjective color differences are “computed” in neuronal nets being represented by amplitudes of evoked potentials triggered by color change. [Shepard]

The history of comparative psychology is replete with proclamations of human uniqueness. Locke and Morgan denied animals relational thought; Darwin opened the door to that possibility. Penn et al. may be too quick to dismiss the cognitive competences of animals. The developmental precursors to relational thought in humans are not yet known; providing animals those prerequisite experiences may promote more advanced relational thought.

Although we agree that ritualized behavior is a mystery that calls out for an explanation, we do not think that the proposed domain-specific two-component system offers an empirically well-justified and theoretically parsimonious description of the phenomena. Instead, we believe that the deployment of domain-general mechanisms based on choice of actions could also explain the essential features of ritualized behavior.

Group assortative biases are stronger in regions where pathogen stress has been historically prevalent. Pushing the logic of this approach, extensions should include investigations of how cultural norms related to prosociality and relational striving may also covary with regional pathogen stress. Likewise, the pan-specific observation that diseased animals show decreased motor activity to facilitate recovery suggests that norms relevant to sickness behaviors may also vary as a function of regional parasite stress.

Fitness interdependence is the degree to which two or more organisms influence each other's success in replicating their genes. Identity fusion may be a proximate mechanism that aligns behavior with fitness interdependence. Although identity fusion may usually lead to behaviors that are fitness enhancing, in evolutionarily novel environments, it may be hijacked in ways that are highly detrimental to fitness.

Low-income environments have been associated with greater levels of impulsive behavior, which contribute to the higher debt and obesity rates that further perpetuate current wealth and health disparities. In this commentary, we describe how this might be explained by an appeal to “incentive hope” and the motivational drive toward consumption triggered by the future uncertainty these groups face.

Imaginary worlds recur across hunter-gatherer narrative, suggesting that they are an ancient part of human life: to understand their popularity, we must examine their origins. Hunter-gatherer fictional narratives use various devices to encode factual information. Thus, participation in these invented worlds, born of our evolved ability to engage in pretense, may provide adaptations with information inputs that scaffold their development.

Although psychology has long professed that perception predicts action, the strength of the evidence supporting the statement depends on the ecological validity of the technologies and paradigms used, particularly those that track eye movements, supporting Cesario's argument. While right to call for ecological validity, Cesario's model fails to account for individual differences in visual experience perceivers have when presented with the same stimulus.

The study of cultural complexity is entwined with ancestors myths from contemporary cosmology. Gowdy & Krall expose this mythology by arguing that complexity emerged from economic changes following cultivation. There is more, however, to the development of cultural complexity. Complexity can emerge from abundant energy or from addressing societal problems, which compels still further energy production.

In order to benefit from the advantages of localist coding, neural models that feature winner-take-all representations at the top level of a network hierarchy must still solve the computational problems inherent in distributed representations at the lower levels.

Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.