We argue that if a different definition of sentence complexity is adopted and processing capacity is assessed in a way that is consistent with that definition, then the Caplan & Waters distinction between interpretive versus postinterpretive processing is unnecessary insofar that it applies to the thematic role assignment in relative-clause sentences.

Among Pylyshyn's most important questions is determining the boundaries of early vision. A simple stimulus illustrates that, in addition to the dominant percept, most observers can perceive alternative interpretations of 3-D surface layout only after provided with suggestions. These observations may indicate that cognitive influences reach the stages of visual processing where 3-D surface configurations are resolved.

Although some types of cognition may not affect early vision, there is ample evidence that other types of cognition do. Evidence indicating that early vision is penetrable by direct manipulation of viewers' perceptual intentions and by knowledge of the structure of familiar objects is reviewed, and related to both the Pylyshyn target article and Fodor (1983).

Palmer demarcates the bounds of our understanding of color experience by symmetries in the color space. He claims that if there are symmetries, there can be functionally undetectable color transformations. However, even if there are symmetries, Palmer's support for the possibility of undetectable transformations assumes phenomenal internalism. Alternatively, phenomenal externalism eliminates Palmer's limit on our understanding of color experience.

A distinction between interpretive processing and post-interpretive processing calls for a consideration of interface relations in systems of verbal memory. Syntactic movement of a phrase and the cognitive system of thought/mind interact. Systems of declarative memory and procedural memory interact.

Campbell's target article is a stimulating attempt to extend our understanding of sex differences in risk-taking behaviors. However, Campbell does not succeed in demonstrating that her account adds explanatory power to those (e.g., Daly & Wilson 1994) previously proposed. In particular, little effort was made to explore the causal links between survival (staying alive) and reproduction.

Dienes & Perner present a very interesting analysis of two types of knowledge. It is not clear, however, that the words “implicit” and “explicit” are the best basis on which to build a theory of the two types of knowledge. One is also left uncertain as to whether this theory is the best way of ordering the greatest possible amount of relevant data in a way that yields the simplest account possible.

We attempt to resolve some details of Barsalou's theory. (1) The mechanism that guides selection of perceptual information may be the efferent control of activity. (2) Information about a world that is not accessible to the senses can be constructed in the process of semiotic mediation. (3) Introspection may not be a kind of perception; rather, semiotically mediated information processing might be necessary for the emergence of introspection.

Barsalou's theory rightly emphasizes the perceptual basis of cognition. However, the perceptual symbols that he proposes seem ill suited to carry the representational burden entailed by the architecture in which they function, given that Barsalou accepts the requirement for productivity. A more radical proposal is needed in which symbols are largely external to the cognizer and linked to internal states via perception.

In this commentary I point out that Palmer mislocates the source of the inverted spectrum, misrepresents the nature of colour science, and offers no reason for prefering one colour machine over another. I conclude nonetheless that talk about “colour machines” is a step in the right direction.

Normals display selective deficits in morphology and syntax under adverse processing conditions. Digit loads do not impair processing of passives and object relatives but do impair processing of grammatical morphemes. Perceptual degradation and temporal compression selectively impair several aspects of grammar, including passives and object relatives. Hence we replicate Caplan & Waters's specific findings but reach opposite conclusions, based on wider evidence.

How can the impenetrability hypothesis be empirically tested? We comment on the role of signal detection measures, suggesting that context effects on discriminations for which post-perceptual cues are irrelevant, or on neural activity associated with early vision, would challenge impenetrability. We also note the great computational power of the proposed pre-perceptual attention processes and consider the implications for testability of the theory.

When aggression is conceptualised in terms of a cost-benefit ratio, sex differences are best understood by a consideration of female costs as well as male benefits. Benefits must be extremely high to outweigh the greater costs borne by females, and circumstances where this occurs are discussed. Achievement of dominance is not such a circumstance and evidence bearing upon women's egalitarian relationships is reviewed. Attempts to explain sex differences in terms of sexual dimorphism, sex-of-target effects, social control, and socialisation are found to be inadequate. The suggestion that the stigmatisation of female aggreession arises not from patriarchal imposition but from statistical rarity (resulting from evolutionary pressures) is given serious consideration. Two hypotheses (“internal read-out” versus social/epidemiological representations) are described to explain the relationship between sex differences in behaviour and corresponding lay explanations.

The modernist and scientific juxtaposition of object and subject are inappropriate when investigating the nature of “knowledge.” This commentary argues that the usual methodological dichotomy fails when it is applied to the domain of “knowledge.” The two instead coalesce within the topic itself, demanding the most careful self-awareness.

We agree with Caplan & Waters that there are problems with the single-resource theory of sentence comprehension. However, we challenge their dual-resource alternative on theoretical and empirical grounds and point to a more coherent solution that abandons the notion of working memory resources.

Palmer's color room argument is first contrasted with a different argument by Tim Maudlin against the sufficiency thesis of strong AI. This thesis turns out to be false and hence we need to determine the relevant supervenience base of phenomenal consciousness. That could be done by causal theories and intraindividual experiments. Finally, even if we cannot explain the intrinsic character of conscious states, we may be able to know what the experience of another person is like.

Early vision provides general information about the environment that can be used for motor control or navigation and more specialized information that can be used for object recognition. The general information is likely to be insensitive to cognitive factors, but this may not be entirely true for the information used in model-based recognition.

The meanings of abstract concepts depend on context. Perceptual symbol systems (PSS) provide a powerful framework for representing such context. Whereas a few expected difficulties for simulations are consistent with empirical findings, the theory does not clearly predict simulations of specific abstract concepts in a testable way and does not appear to distinguish abstract noun concepts (like truth) from their stem concepts (such as true).

Some cases of implicit knowledge involve representations of (implicitly) known propositions, but this is not the only important type of implicit knowledge. Chomskian linguistics suggests another model of how humans can know more than is accessible to consciousness. Innate capacities to focus on a small range of possibilities, thereby ignoring many others, need not be grounded by inner representations of any possibilities ignored. This model may apply to many domains where human cognition “fills a gap” between stimuli and judgment.

If the cortex is an associative memory, strongly connected cell assemblies will form when neurons in different cortical areas are frequently active at the same time. The cortical distributions of these assemblies must be a consequence of where in the cortex correlated neuronal activity occurred during learning. An assembly can be considered a functional unit exhibiting activity states such as full activation (“ignition”) after appropriate sensory stimulation (possibly related to perception) and continuous reverberation of excitation within the assembly (a putative memory process). This has implications for cortical topographies and activity dynamics of cell assemblies forming during language acquisition, in particular for those representing words. Cortical topographies of assemblies should be related to aspects of the meaning of the words they represent, and physiological signs of cell assembly ignition should be followed by possible indicators of reverberation. The following postulates are discussed in detail: (1) assemblies representing phonological word forms are strongly lateralized and distributed over perisylvian cortices; (2) assemblies representing highly abstract words such as grammatical function words are also strongly lateralized and restricted to these perisylvian regions; (3) assemblies representing concrete content words include additional neurons in both hemispheres; (4) assemblies representing words referring to visual stimuli include neurons in visual cortices; and (5) assemblies representing words referring to actions include neurons in motor cortices. Two main sources of evidence are used to evaluate these proposals: (a) imaging studies focusing on localizing word processing in the brain, based on stimulus-triggered event-related potentials (ERPs), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), and (b) studies of the temporal dynamics of fast activity changes in the brain, as revealed by high-frequency responses recorded in the electroencephalogram (EEG) and magnetoencephalogram (MEG). These data provide evidence for processing differences between words and matched meaningless pseudowords, and between word classes, such as concrete content and abstract function words, and words evoking visual or motor associations. There is evidence for early word class-specific spreading of neuronal activity and for equally specific high-frequency responses occurring later. These results support a neurobiological model of language in the Hebbian tradition. Competing large-scale neuronal theories of language are discussed in light of the data summarized. Neurobiological perspectives on the problem of serial order of words in syntactic strings are considered in closing.