It is proposed that cortical activity is normally coordinated across synaptically connected areas and that this coordination supports cognitive coherence relations. This view is consistent with the NMDA- hypoactivity hypothesis of the target article in regarding disorganization symptoms in schizophrenia as arising from disruption of normal interareal coordination. This disruption may produce abnormal contextual effects in the cortex that lead to anomalous cognitive coherence relations.

Single-unit data from the cortex of monkeys performing working-memory tasks support the main point of the target article. Those data, however, also indicate that the activation of long-term memory is essential to the processing of all cognitive functions. The activation of cortical long-term memory networks is a key neural mechanism in attention (working memory is a form thereof), perception, memory acquisition and retrieval, intelligence, and language.

The Newell Test as it is proposed by Anderson & Lebiere (A&L) has the disadvantage of being too positivistic, stressing areas a theory should cover, instead of attempting to exclude false predictions. Nevertheless, Newell's list can be used as the basis for a more stringent test with a stress on the falsifiability of the theory.

This commentary focuses on two aspects of eye movement behaviour that E-Z Reader 7 currently makes no attempt to explain: the influence of higher order psycholinguistic processes on fixation durations, and orthographic influences on initial and refixation locations on words. From our understanding of the current version of the model, it is not clear how it may be readily modified to account for existing empirical data.

Unlike all other lateral specializations, the necessity for unilateral dominance is clear only for the case of the motor control of the speech organs lying on the midline of the body and innervated from both hemispheres. All functional asymmetries are likely to be a consequence of this asymmetry of executive control.

Metaknowledge may not always facilitate acquisition of knowledge or performance of complex tasks. A pigeon, for example, depending on the task, can report what it is doing even if it cannot perform the task well, and it can fail to report what it is doing when it performs the task well (Shimp 1982; 1983).

Reichle et al. specify two assumptions as being basic to E-Z Reader: Words are sequentially attended during fixations, and saccades are triggered by a cognitive event. We point out that there is little evidence for the first assumption and counterevidence for the second. Also, the labile/nonlabile stage distinction in saccade preparation seems to be contrary to current evidence. An alternative explanation of saccade onset times in reading assumes that saccades are strategically generated, independent of language processing, but are delayed on a probabilistic basis by processing difficulties.

Evidence for a dysfunction in cognitive coordination in schizophrenia is emerging, but it is not specific enough to prove (or disprove) this long-standing hypothesis. Many aspects of the external world are spatially mapped in the brain. A comprehensive internal representation relies on integration of information across space. Focus on spatial integration in the perceptual and cognitive processes will generate empirical data that shed light on the pathophysiology of schizophrenia.

Neural models have proposed how short-term memory (STM) storage in working memory and long-term memory (LTM) storage and recall are linked and interact, but are realized by different mechanisms that obey different laws. The authors' data can be understood in the light of these models, which suggest that the authors may have gone too far in obscuring the differences between these processes.

Recent studies with human infants and nonhuman primates reveal that posture interacts with the expression and stability of handedness. Converging results demonstrate that quadrupedal locomotion hinders the expression of handedness, whereas bipedal posture enhances preferred hand use. From an evolutionary perspective, these findings suggest that right-handedness may have emerged first, following the adoption of bipedal locomotion, with speech emerging later.

Smith et al. demonstrate the viability of animal metacognition research. We commend their effort and suggest three avenues of research. The first concerns whether animals are explicitly aware of their metacognitive processes. The second asks whether animals have metaknowledge of their own uncertain responses. The third issue concerns the monitoring/control distinction. We suggest some ways in which these issues elucidate metacognitive processes in nonhuman animals.

Cognitive architectures, like programming languages, make commitments only at the implementation level and have limited explanatory power. Their universality implies that it is hard, if not impossible, to justify them in detail from finite quantities of data. It is more fruitful to focus on particular tasks such as language understanding and propose testable theories at the computational and algorithmic levels.

Smith et al. present a model that they suggest may clarify aspects of the phylogenetic distribution of metacognition, based on observation of what they call uncertainty monitoring. Although they suggest that their model is supported by data collected using monkeys and dolphins, their interpretation that nonhuman animal behaviors parallel thought processes in humans may be unwarranted. The model presented by Smith et al. is inconsistent with current theories and empirical findings on the comparative aspects of metacognition. We present three oversights of the model and extend our critique to include a brief discussion of animal self-awareness, as well as current neuropsychological perspectives on metacognitive processing in humans.

Modern investigators of cognition ask about the conditions under which faculties occur rather than about their existence. This tendency, combined with the axiom of parsimony, emphasizes a paradigm shift in the fundamental principles of economic thought in science, mimicking evolutionary conceptualizations. The Ruchkin model of memory-related brain activity replaces less economic models. From interdisciplinary approaches, proceduralist models for other memory-related processes analogously support this model.

Modelling human reasoning characterizes the fundamental human cognitive capacity to describe our past experience and use it to form expectations as well as plan and direct our future actions. Natural language semantics analyzes dynamic forms of reasoning in which the real-time order determines the temporal relations between the described events, when reported with telic simple past-tense clauses. It provides models of human reasoning that could supplement ACT-R models.

E-Z Reader fits key parameters from one corpus of eye movement data, but has not really been tested with new data sets. More critically, it is argued that the key mechanism driving eye movements – a serial process involving a proportion of word recognition time – is implausible on the basis of a broad range of experimental findings.

Mechanisms that contribute to perceptual processing dysfunction in schizophrenia were examined by Phillips & Silverstein, and formulated as involving disruptions in both local and higher-level coordination of signals. We agree that dysfunction in the coordination of cognitive functions (disconnection) is also indicated for many of the linguistic processing deficits documented for schizophrenia. We suggest, however, that it may be necessary to add a timing mechanism to the theoretical account.

Corballis's explanation for right-handedness in humans relies heavily on the gestural protolanguage hypothesis, which he argues for by a series of “intuition pumps.” Scrutinizing the mirror system hypothesis and modern gesture as components of the argument, we find that they do not provide the desired evidence of a gestural precursor to speech.

The Newell Test is an important step in advancing our understanding of cognition. One critical constraint is missing from this test: A cognitive architecture must be self-contained. ACT-R and connectionism fail on this account. I present an alternative proposal, called Distributed Adaptive Control (DAC), and expose it to the Newell Test with the goal of achieving a clearer specification of the different constraints and their relationships, as proposed by Anderson & Lebiere (A&L).

Evidence for the contribution of the neocortex to memory is overwhelming. However, the theory proposed by Ruchkin et al. does not only ignore subcortical contributions, but also introduces an unnecessary and empirically unsupported division between the posterior cortex, assumed to represent information, and the prefrontal cortex, assumed to control activation. We argue instead that the representational power of the neocortex is not restricted to its posterior part.