An intervening gestural stage in language evolution, though seductive, is ultimately redundant, and is not necessarily supported by modern human or chimp behaviour. The findings and arguments offered from mirror neurones, anatomy, and lateralization are capable of other interpretations, and the manipulative dextrality of chimps is under-recognized. While language certainly possesses certain unique properties, its roots are ancient.

The concept of locally specialized functions dominates research on higher brain function and its disorders. Locally specialized functions must be complemented by processes that coordinate those functions, however, and impairment of coordinating processes may be central to some psychotic conditions. Evidence for processes that coordinate activity is provided by neurobiological and psychological studies of contextual disambiguation and dynamic grouping. Mechanisms by which this important class of cognitive functions could be achieved include those long-range connections within and between cortical regions that activate synaptic channels via NMDA-receptors, and which control gain through their voltage-dependent mode of operation. An impairment of these mechanisms is central to PCP-psychosis, and the cognitive capabilities that they could provide are impaired in some forms of schizophrenia. We conclude that impaired cognitive coordination due to reduced ion flow through NMDA-channels is involved in schizophrenia, and we suggest that it may also be involved in other disorders. This perspective suggests several ways in which further research could enhance our understanding of cognitive coordination, its neural basis, and its relevance to psychopathology.

Against the view that metacognition is a capacity that parallels theory of mind, it is argued that metacognition need involve neither metarepresentation nor semantic forms of reflexivity, but only process-reflexivity, through which a task-specific system monitors its own internal feedback by using quantitative cues. Metacognitive activities, however, may be redescribed in metarepresentational, mentalistic terms in species endowed with a theory of mind.

The E-Z Reader model assumes that the parafoveal selection for fixation and the subsequent selection for attention allocation encompass the same spatially distinct letter cluster. Recent data suggest, however, that an individual letter sequence is selected for fixation and that more than one letter sequence can be selected for attention allocation (processing).

This commentary compares clinical aspects of ketamine with the amphetamine model of schizophrenia. Hallucinations and loss of insight, associated with amphetamine, seem more schizophrenia-like. Flat affect encountered with ketamine is closer to the clinical presentation in schizophrenia. We argue that flat affect is not a sign of schizophrenia, but rather, a risk factor for chronic schizophrenia.

The Newell Test is an ambitious and promising project, but not without pitfalls. Some of the current criteria are not theoretically neutral, whereas others are unhelpful. To improve the test, the learning and development criteria are reviewed and revised, which suggests adding a maturation criterion as well. Such changes should make the Newell Test more general and useful.

We add evidence in support of Corballis's gestural theory of language. Using transcranial magnetic stimulation, we found that productive and receptive linguistic tasks excite the motor cortices for both hands. This indicates that the language and the hand motor systems are still tightly linked in modern man. The bilaterality of the effect, however, implies that lateralisation is a secondary issue.

In this commentary, the formation of “pre-iconic” visual-prime persistence is described in the context of prime-specific, independent-component activation at prefrontal and posterior EEG-recording sites. Although this activity subserves neural systems that are near identical to those described by Ruchkin and colleagues, we consider priming to be a dynamic process, identified with patterns of coherence and temporal structure of very high precision.

Phillips & Silverstein argue that a range of cognitive disturbances in schizophrenia result from a deficit in cognitive coordination attributable to NMDA receptor dysfunction. We suggest that the viability of this hypothesis would be further supported by explicit implementation in a computational framework that can produce quantitative estimates of the behavior of both healthy individuals and individuals with schizophrenia.

I present reasons for adding an embodiment criterion to the list defended by Anderson & Lebiere (A&L). I also entertain a likely objection contending that embodiment is merely a type of dynamic behavior and is therefore covered by the target article. In either case, it turns out that neither connectionism nor ACT-R do particularly well when it comes to embodiment.

With reference to Ruchkins et al.'s framework, this commentary briefly considers the history of working memory, and whether, heuristically, this is a useful concept. A neuropsychologically motivated critique is offered, specifically with regard to the recent trend for working-memory researchers to conceptualise this capacity more as a process than as a set of distinct task-specific stores.

E-Z Reader is a highly successful model of eye-movement control, employing the notion of a serial-sequential attentional spotlight switched from word to word. Evidence of parallel processing of words in text calls this notion into question. Modifications to the model to accommodate this evidence are possible but will not address the fundamental objection that reading should not be seen as “surrogate listening.”

Corballis's claim that the origin of syntax lies in solely gesture is contested. His scenario does not explain why constraints on syntactic “movement” are apparently part of the human biological endowment for language. It also does not pay enough attention to the internal structure of sentences, and how they contrast with other linguistic units such as noun phrases.

We suggest that the phenomenon of uncertainty monitoring in nonhuman animals contributes richly to the conception of nonhuman animals' self-monitoring. We propose that uncertainty may play a role in the emergence of new forms of behavior that are adaptive. We recommend that Smith et al. determine the extent to which the uncertain response transfers immediately to other test paradigms.

The notion that the working-memory system is not to be located in the prefrontal cortex, but rather constituted by the interplay between temporal and frontal areas, is of some attraction. However, at least for the domain of sentence comprehension, this perspective is promoted on the basis of sparse data. For this domain, the authors not only missed out on the chance to systematically integrate event-related brain potential (ERP) and neuroimaging data when interpreting their own findings on semantic aspects of working memory, but also neglected syntactic aspects of working memory and computation altogether.

What do the relationships observed in the occurrence of various limb, facial, and speech apraxias following left hemisphere damage mean for Corballis's theory? What does the right hemisphere's role in nonpropositional and automatic speech production tell us about the coevolution of right hand preference and speech; how could the possibility that the right hemisphere may be “dominant” for some aspects of speech be accommodated by his theory?

The target article presents a model for schizophrenia extending four levels of abstraction: molecules, cells, cognition, and syndrome. An important notion in the model is that of coordination, applicable to both the level of cells and of cognition. The molecular level provides an “implementation” of the coordination at the cellular level, which in turn underlies the coordination at the cognitive level, giving rise to the clinical symptoms.

This commentary examines one aspect of the target article – the comparison of ACT-R with connectionist models. It argues that conceptions of connectionist models should be broadened to cover the whole spectrum of work in this area, especially the so-called hybrid models. Doing so may change drastically ratings of connectionist models, and consequently shed more light on the developing field of cognitive architectures.

We question the assumption of serial attention shifts and the assumption that saccade programs are initiated or canceled only after stage one of word identification. Evidence: (1) Fixation durations prior to skipped words are not consistently higher compared to those prior to nonskipped words. (2) Attentional modulation of microsaccade rate might occur after early visual processing. Saccades are probably triggered by attentional selection.

When animals choose between completing a cognitive task and “escaping,” proper interpretation of their behavior depends crucially on methodological details, including how forced and freely chosen tests are mixed and whether appropriate transfer tests are administered. But no matter how rigorous the test, it is impossible to go beyond functional similarity between human and nonhuman behaviors to certainty about human-like consciousness.