Strong recent selection for social cognition may well explain the persistence of genes that predispose to schizophrenia. The specific mechanism responsible may be a skewed fitness function in which selection pushes the mean for advantageous mental traits perilously close to a “fitness cliff” where the system fails catastrophically in some individuals.

All mammals have social brains, and there is presently no evidence that humans have relatively more genetically dictated social brain circuitry than other species. The postulation that schizophrenia arises from disruption of brains systems uniquely devoted to social traits is obviated not only by the large number of anatomical and biochemical brain differences, but also by nonsocial symptoms of schizophrenic disorders.

The most developed and the latest-to-mature mental skills represented in the creation of mono- versus polysemantic contexts are related respectively to the left and right frontal lobe. A polysemantic way of thinking is responsible for the subject's successful integration in the polydimensional world. The functional insufficiency of this right-hemispheric way of thinking displays a predisposition toward the development of mental disorders, including schizophrenia.

Evolutionary theories of schizophrenia must account for the maintenance of putative alleles in past and present populations despite reduced fitness among the affected. Such models must also account for extant intersex and population-level variability in the expression of schizophrenia. We argue that genetic balanced-polymorphism hypotheses remain the most robust in terms of modeling and testing these processes in populations.

We discuss how Burns' conception may be further extended to integrate research on eye movement abnormalities, but then point to a contradiction between Burns' conception of schizophrenia as the genetic price for human social life and the diffusion tensor imaging (DTI) data, which constitute his central piece of evidence.

Schizophrenia may not have reduced reproductive success in ancestral times as much as it does today, so explaining how genes for it evolved is more understandable given this prehistoric perspective. Ethological analysis of schizophrenia – understanding how basic emotional behaviors, such as dominance striving, are affected by the condition – might prove useful for comprehending and treating its social emotional symptoms.

I defend the case for an evolutionary theory of schizophrenia and the social brain, arguing that such an exercise necessitates a broader methodology than that familiar to neuroscience. I propose a reworked evolutionary genetic model of schizophrenia, drawing on insights from commentators, buttressing my claim that psychosis is a costly consequence of sophisticated social cognition in humans. Expanded models of social brain anatomy and the spectrum of psychopathologies are presented in terms of upper and lower social brain and top-down and bottom-up processes. Finally, I argue that cerebral asymmetry evolved as an emergent property of primary intrahemispheric reorganisation in hominoids.

The suggestion of seeking specificity in a higher-order array is attractive, but Stoffregen & Bardy (S&B) fail to provide a compelling empirical basis to their claim that specificity exists solely in the global array. Using the example of relative motion, the alternate hypotheses that must be considered are presented.

Strong between- and within-animal differences during spatial activities lead us to claim that a given animal is directly sensitive to a given substructure of the global array. This vicarious subset is not cut out by the senses but by redundancies emerging from physical properties. We argue that the subset is not a single ambient array, or a combination of single ambient arrays, but a complex holistic part of the global array.

Stoffregen & Bardy (S&B) make the point that the statement “I am moving” made by subjects in a “swinging room” cannot be explained as an illusion of motion, and there is thus no perceptual illusion. In this they are correct. There is in fact motion, but of the environment. We argue that the subjects misinterpret this because the information to the visual system is ambiguous and also deceiving.

The analogy between the rules that subtend ventriloquism and bimodal neurons responding suggests a possible neural mechanism for audiovisual interactions in spatial scene analysis. Perinatal data, such as those on synesthesia, sensory deprivation, and sensory surstimulation, as well as neuroanatomical evidence for transitory intersensory connections in the brain support the view that audition and vision are bound together at birth.

Sensation should indeed be understood globally: some infant behaviors do not make sense on the model of separate senses; neonates of all species lack time to learn about the world by triangulating among different senses. Considerations of natural selection favor a global understanding; and the global interpretation is not as opposed to traditional work on sensation as might seem.

The existence of sensory convergence does not establish that the senses function as a single unified perceptual system. Reality is fully specified only by a one:many mapping onto the totality of energy arrays, and these provide alternative frames of reference for movement. It is therefore possible that higher order crossmodal relationships are detected by skilled perceivers, but this has not been confirmed empirically.

The new commentaries raise important issues about the target article (Stoffregen & Bardy 2001). The commentaries also highlight some assumptions, often implicit, that underlie traditional interpretations of perception. We argue that evaluation of the global array and its implications for perception requires both analytical research on specification in the global array and new empirical research on the use of information in the global array for the control of action.

Selection theory requires multiple, simultaneously-actualized states. In cognition, each thought changes the “selection pressure” against which the next is evaluated; they are not simultaneously selected amongst. Cognitive change occurs not through selection among discrete “neural configurations,” but through interaction between conceptual web and context. This introduces a non-Kolmogorovian probability distribution, hence a classical formalism (e.g., selection theory) cannot be used.

If selection is interpreted as involving repeated cycles of replication, variation, and environmental interaction so structured that environmental interaction causes replication to be differential, then selection in gene-based biological evolution and the reaction of the immune system to antigens are relatively unproblematic examples of selection processes. Operant learning and cultural evolution pose more serious problems. In this response we deal with operant learning as a selection process.

Although the sensorimotor account is a significant step forward, it cannot explain experiences of entoptic phenomena that violate normal sensorimotor contingencies but nonetheless are perceived as visual. Nervous system structure limits how they can be interpreted. Neurophysiology, combined with a sensorimotor theory, can account for space constancy by denying the existence of permanent representations of states that must be corrected or updated.

O'Regan & Noë's (O&N's) theoretical framework for studying visual perception and awareness is intriguing. This framework, based on sensorimotor contingency, can be examined in recent visual brain theories using neuroimaging methodologies. Here, I consider how a working memory (WM) system explains the sensorimotor account of visual consciousness. I believe WM inside the brain provides at least partial support for O&N's theory.

Bergson, writing in 1896, anticipated “sensorimotor contingencies” under the concept that perception is “virtual action.” But to explain the external image, he embedded this concept in a holographic framework where time-motion is an indivisible and the relation of subject/object is in terms of time. The target article's account of qualitative visual experience falls short for lack of this larger framework.

O'Regan & Noë's (O&N's) explanation of our stream of experience as activities depends on their denial of that palpable, most real aspect of experience: what they call “qualitative experience.” Given the ontological primacy of the qualitative givenness of our experience and the complete absence of actions as experiences in our stream of consciousness, though, all such reductionistic attempts must fail.