Bloom masterfully captures the state-of-the-art in the study of lexical acquisition. He also exposes the extent of our ignorance about the learning of names for non-observables. HCLMW adopts an innatist position without adopting modularity of mind; however, it seems likely that modularity is needed to bridge the gap between object names and the rest of the lexicon.

Bloom's eloquent and comprehensive treatment of early word learning holds that social intention is foundational for language development. While we generally support his thesis, we call into question two of his proposals: (1) that attention to social information in the environment implies social intent, and (2) that infants are sensitive to social intent at the very beginnings of word learning.

Acquisition of word meanings, or vocabulary, reflects general mental ability (psychometric g) more than than do most abilities measured in test batteries. Among diverse subtests, vocabulary is especially high on indices of genetic influences. Bloom's exposition of the psychological complexities of understanding words, involving the primacy of concepts, the theory of mind, and other processes, explains vocabulary's predominant g saturation.

Bloom makes a strong case that word meaning acquisition does not require a dedicated word learning system. This conclusion, however, does not argue against a dedicated language acquisition system for syntax, morphology, and aspects of semantics. Critical questions are raised as to why word meaning should be so different from other aspects of language in the course of acquisition.

This discussion argues that for many word meanings, the child has to assemble a new category, using relatively slow information-sifting processes. This does not cause high semantic errors, because children probably hold off using a word until much such sifting has occurred, rather than producing the new word as soon as they have any information on it.

Research on children's and adults' concepts embodies very different assumptions of how concepts are structured, as reflected in their experimental designs. Developmental studies seem to assume that categories contain highly similar objects that can all be identified from one or two examples. If concepts are more like those tested in adult experiments, research on word learning may be misleading.

Bloom's domain general theory remains strictly cognitive and individualistic. By ignoring the contribution of social interaction and collective construction of concepts, he fails to solve the word learning problem.

Bloom's theory of word learning has difficulty accounting for children's verb acquisition. There is no predominant preverbal event concept, akin to the preverbal object concept, to direct children's early event-verb mappings. Children may take advantage of grammatical and linguistic information in verb acquisition earlier than Bloom allows. A distinction between lexical and grammatical learning is difficult to maintain for verb acquisition.

The theoretical framework of Bloom's account of child word learning is here assessed only for initial plausibility and neural plausibility. The verdict on both dimensions is low, largely due to the size and character of knowledge it is claimed that the child brings to the task. It is suggested that elements of constructivist accounts could profitably be drawn from to reduce this implausibility.

At first, Bloom's theory appears inimical to empiricism, since he credits very young children with highly sophisticated cognitive resources (e.g., a theory of mind and a belief that real kinds have essences), and he also attacks the empiricist's favoured learning theory, namely, associationism. We suggest that, on the contrary, the empiricist can embrace much of what Bloom says.

We propose that Bloom's focus on cognitive factors involved in word learning still lacks a broader perspective. We emphasize the crucial relevance of working memory in learning elements of language. Specifically, we demonstrate through our data that in impaired populations knowledge of some linguistic elements can be dissociated according to the subcomponent of working memory (visual or verbal) involved in a task. Further, although Bloom's concentration on theory of mind as a precondition for word learning is certainly correct, theory of mind being a necessary condition does not make it a sufficient one. On the basis of our studies we point out the importance of a theory of mind related goal preference in acquiring spatial language. In general, we claim that more specific cognitive preferences and constraints should be outlined in detail for the preconditions of acquiring linguistic elements.

Bloom's book can be viewed as a long argument for an anti-Whorfian conclusion. According to Bloom, word learning is usually a process of mapping new words to pre-existing concepts. But an exception to this generalization – the learning of words from linguistic context – poses a problem for Bloom's anti-Whorfian argument.

We propose that in addition to children's requests for word names being a reflection of an understanding of the referential nature of words, they may also be requests for adult's teaching. These possible requests for teaching among toddlers, along with other indications, suggest that teaching may be a natural cognition that may be related to the development of theory of mind.

Although Bloom gives more credit to social cognition (mind reading) than do most other theorists of word learning, he does not go far enough. He still relies fundamentally on a learning process of association (or mapping), neglecting the joint attentional and cultural learning skills from which linguistic communication emerges at one year of age.

Bloom's book underscores the importance of specifying the role of words and grammar in cognition. We propose that the cognitive power of language lies in the lexicon rather than grammar. We suggest ways in which studies involving children and patients with aphasia can provide insights into the basis of abstract cognition in the domain of number and mathematics.

Bloom provides a masterful synthesis of recent advances in word-learning, placing them within the framework of abiding theoretical issues. I will augment and challenge his approach by underscoring the significance of word extension for questions concerning (a) the origin and evolution of infants' expectations, and (b) domain-specificity in word-learning.

This book is an excellent and accessible overview of the position that children learn the meanings of words by applying a variety of nonlinguistic cognitive tools to the problem. We take issue with Bloom's emphasis on Theory of Mind as an explanatory mechanism for language learning; and with his claim that only unitary objects are nameable.

In order to account for how children can generalize words beyond a very limited set of labeled examples, Bloom's proposal of word learning requires two extensions: a better understanding of the “general learning and memory abilities” involved, and a principled framework for integrating multiple conflicting constraints on word meaning. We propose a framework based on Bayesian statistical inference that meets both of those needs.

How Children Learn the Meanings of Words (HCLMW) defends the theory that words are learned through sophisticated and early-emerging cognitive abilities that have evolved for other purposes; there is no dedicated mental mechanism that is special to word learning. The commentators raise a number of challenges to this theory: Does it correctly characterize the nature and development of early abilities? Does it attribute too much to children, or too little? Does it only apply to nouns, or can it also explain the acquisition of words such as verbs and determiners? More general issues are discussed as well, including the role of the input, the relationship between words and concepts, and debates over nativism, adaptationism, and modularity.

Pessoa et al. (1998a) underexposed the broad and rich variety of stimuli in the amodal completion domain. The disambiguation of occluded shapes depends on very specific figural properties. Elaborations on such disambiguations of rich and complex stimuli, tied up with a visuo-cognitive origin of amodal completion, further position Pessoa et al.'s considerations on neural filling-in and the personal-subpersonal distinction.