The authors' attempt to explore the ability of animals to monitor how certain they are of their choice behavior, necessarily fails both in their effort to include “higher” mammals (such as monkeys and dolphins) in the class of metacognitive organisms (humans) and in their conclusion that “lower” organisms are not capable of similar behavior.

This commentary takes issue with Corballis's claim to have presented a falsifiable hypothesis. It argues that Corballis has instead presented a framework of weak inferences that, although unfalsifiable, might help to constrain future theory-building.

The current model appears comprehensive but is probably not applicable to a writing system like Japanese, which has unspaced text, because the model is mainly based on English. The span size difference (smaller for Japanese than for English) may be a result of high-level working memory-based attentional processing and not of low-level processing. Further, neural correlates of the model are discussed in terms of central executive function.

The claim that the disorganized subtype of schizophrenia results from glutamate hypofunction is enhanced by consideration of current subtypology of schizophrenia, symptom definition, interdependence of neurotransmitters, and the nature of the data needed to support the hypothesis. Careful specification clarifies the clinical reality of disorganization as a feature of schizophrenia and increases the utility of the subtype.

I discuss evidence for direct linguistic control of refixations and argue that the E-Z Reader model's account of refixations requires elaboration or revision.

There was a strong consensus in the commentaries that animals' performances in metacognition paradigms indicate high-level decisional processes that cannot be explained associatively. Our response summarizes this consensus and the support for the idea that these performances demonstrate animal metacognition. We amplify the idea that there is an adaptive advantage favoring animals who can – in an immediate moment of difficulty or uncertainty – construct a decisional assemblage that lets them find an appropriate behavioral solution. A working consciousness would serve this function well. This explains why animals may have the functional equivalent of human declarative consciousness. However, like other commentators who were friendly to this equivalence, we approach carefully the stronger claims that animals' metacognitive performances imply full-blown self-awareness or phenomenal consciousness.

We discuss the commentators' interesting ideas for future research, as well as their intriguing ideas about the evolution and development of metacognition and its relation to theory of mind. We also discuss residual confusions about existing research and remaining methodological issues.

In the verbal domain, there is only very weak evidence favoring the view that working memory is an active state of long-term memory. We strengthen existing evidence by reviewing two recent fMRI studies of verbal working memory, which clearly demonstrate activation in the superior temporal lobe, a region known to be involved in processing speech during comprehension tasks.

Corballis seems to have not considered two points: (1) the importance of direct selection pressures for the evolution of handedness; and (2) the evolutionary significance of the polymorphism of handedness. We provide arguments for the need to explain handedness in terms of adaptation and natural selection.

The Phillips & Silverstein model of NMDA-mediated coordination deficits provides a useful heuristic for the study of schizophrenic cognition. However, the model does not specifically account for the development of schizophrenia-spectrum disorders. The P&S model is compared to Meehl's seminal model of schizotaxia, schizotypy, and schizophrenia, as well as the model of schizophrenic cognitive dysfunction posited by McCarley and colleagues.

Although we agree with Newell and Anderson & Lebiere (A&L) that a unified theory of cognition is needed to advance cognitive science, we disagree on how to achieve it. A hybrid system can score high in the Newell Test but may not offer a veridical and coherent theory of cognition. A multilevel approach, involving theories at both psychological and brain levels, is suggested.

Right-hand preference for conversational gestures does not imply close connections between the neural systems controlling manual and vocal communication. Use of speech and gestures may dissociate in some cases of focal brain damages. Furthermore, there are limits in the ability to combine spoken words and concurrent hand movements. These findings suggest that discourse production depends on multiple components which probably have different evolutionary origins.

Attentional processes that operate on the contents of memory to produce the activation that is described as working memory by Ruchkin et al. and others, involve a network of brain regions that include both prefrontal and parietal sites. This network appears to mimic the one that is activated by attentional processes that operate on information entering via the senses.

We draw an analogy between Hilbert's program (HP) for mathematics and Newell's program (NP) for cognitive modeling. The analogy reveals that NP, like HP before it, is fundamentally flawed. The only alternative is a program anchored by an admission that cognition is more than computation.

To understand schizophrenia, a linking hypothesis is needed that shows how brain mechanisms lead to behavioral functions in normals, and also how breakdowns in these mechanisms lead to behavioral symptoms of schizophrenia. Such a linking hypothesis is now available that complements the discussion offered by Phillips & Silverstein (P&S).

Reichle et al. argue that the mechanism that determines where to fixate the eyes is controlled mostly by low-level processes. Therefore, unlike other competing models (e.g., the SWIFT model), the E-Z Reader model cannot account for “global” regressions as a result of linguistic difficulties. We argue that the model needs to be extended to account for regressive saccades.

We propose that the fine discrete movements of the tongue as used in speech are what account for the extreme lateralization in humans, and that handedness is a mere byproduct of tongue use. With regard to syntax, we support the Armstrong et al. (1995) proposition that syntax derives directly from gestural motor movements as opposed to facial expressions.

E-Z Reader achieves an impressive fit of empirical eye movement data by simulating core processes of reading in a computational approach that includes serial word processing, shifts of attention, and temporal overlap in the programming of saccades. However, when common assumptions for the time requirements of these processes are taken into account, severe constraints on the time line within which these elements can be combined become obvious. We argue that it appears difficult to accommodate these processes within a largely sequential modeling framework such as E-Z Reader.

This commentary addresses: (a) the problems of definition which have been prominent in the use of the term context in schizophrenia research; (b) potentially useful distinctions and links with other theories of schizophrenic cognition; and (c) possible pathways to schizophrenic symptoms. It is suggested that at least two major aspects of the operation of context may be distinguished and that both may be impaired in schizophrenia.

The criterion of computational universality for an architecture should be replaced by the notion of compliancy, where a model built within an architecture is compliant to the extent that the model allows the architecture to determine the processing. The test should be that the architecture does easily – that is, enables a compliant model to do – what people do easily.

Ruchkin et al.'s view of working memory as activated long-term memory is more compatible with language processing than models such as Baddeley's, but it raises questions about individual differences in working memory and the validity of domain-general capacity estimates. Does it make sense to refer to someone as having low working memory capacity if capacity depends on particular knowledge structures tapped by the task?