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Developmental psychology and developmental neuropsychology have traditionally focused on the study of children. But these two fields are also supposed to be about the study of change, i.e. changes in behavior, changes in the neural structures that underlie behavior, and changes in the relationship between mind and brain across the course of development. Ironically, there has been relatively little interest in the mechanisms responsible for change in the last 15–20 years of developmental research. The reasons for this de-emphasis on change have a great deal to do with a metaphor for mind and brain that has influenced most of experimental psychology, cognitive science and neuropsychology for the last few decades, i.e. the metaphor of the serial digital computer. We will refer to this particu-

“Origins of communicative disorders ” to Elizabeth Bates, and by a grant from the John D. and Catherine T. MacArthur Foundation. We are grateful to Larry Juarez and Meiti Opie The effects of focal brain injury are investigated in the first stages of language development, during the passage from first words to grammar. Parent report and/or free speech data are reported for 53 infants and preschool children between 10- 44 months of age. All children had suffered a single, unilateral brain injury to the left or right hemisphere, incurred before six months of age (usually in the pre- or perinatal period). This is the period in which we should expect to see maximal plasticity, but it is also the period in which the initial specializations of particular cortical regions ought to be most evident. In direct contradiction of hypotheses based on the adult aphasia literature, results from 10- 17 months suggest that children with righthemisphere injuries are at greater risk for delays in word comprehension, and in the gestures that normally precede and accompany language onset. Although there were no differences between left- vs. right-hemisphere injury per se on expressive language, children whose lesions include the left temporal lobe did show significantly greater delays in expressive vocabulary and

The term “aphasia ” refers to acute or chronic impairment of language, an acquired condition that is most often associated with damage to the left side of the brain, usually due to trauma or stroke. We have known about the link between left-hemisphere damage and language loss for more than a century (Goodglass, 1993). For almost as long, we have also known that the lesion/symptom correlations observed in adults do not appear to hold for very young children (Basser, 1962; Lenneberg, 1967). In fact, in the absence of other complications, infants with congenital damage to one side of the brain (left or right) usually go on to acquire language abilities that are well within the normal range (Eisele & Aram, 1995; Feldman, Holland, & Janosky, 1992; Vargha-Khadem, Isaacs, & Muter,

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Aphasia (defined as the loss or impairment of language abilities following acquired brain injury) is strongly associated with damage to the left hemisphere in adults. This well-known finding has led to the hypothesis that the left hemisphere is innately specialized for language, and may be the site of a specific "language organ". However, for over a century we have known that young children with left-hemisphere damage (LHD) do not suffer from aphasia, and in most studies do not differ significantly from children with right-hemisphere damage (RHD). This result provides strong evidence for plasticity, i.e., brain reorganization in response to experience, and constitutes a serious challenge to the language organ hypothesis. This chapter reviews the history of research on language outcomes in children vs. adults with unilateral brain injury, addressing some discrepancies in the literature to date, including methodological confounds that may be responsible for those discrepancies. It also reviews recent prospective studies of children with unilateral injury as they pass through the first stages of language development. Prospective studies have demonstrated specific correlations between lesion site and profiles of language delay, but they look quite different from lesionsymptom correlations in adults, and gradually disappear across the course of language development. The classic pattern of brain organization for language observed in normal adults may be the product rather than the cause of language learning, emerging out of regional biases in information processing that are relevant for language, but only indirectly related to language itself. If those

Savage-Rumbaugh and her colleagues have provided us with yet another ground-breaking investigation into the linguistic abilities (or "quasi-linguistic abilities " — see below) of our nearest phylogenetic neighbor, the chimpanzee. Their monograph begins with some brief but useful reviews of the primate language literature, and the literature on early comprehension and production of language in human children. The authors document the peculiar bias toward production and the relative neglect of comprehension that have characterized the child language literature, and they ask a perfectly reasonable question: If we want to understand what an organism knows about language, isn't comprehension a better place to start? And if we want to compare knowledge of language in two related species, how can we draw any firm conclusions if our work is based exclusively on what the animal can produce?

Three exploratory studies were carried out to determine if there was continuity in the development of language in young children at the upper and lower extremes of the normal continuum, and if it was possible to use variables from an early assessment to predict their language status at a later date. Studies 1 and 2 examined continuity over 6-month period (from approximately 20 to 26 and 13 to 20 months of age, respectively); Study 3 examined continuity from 8 to 30 months of age. Results provided solid evidence for continuity at the group level but no evidence of ability to predict outcome for individual children using the vocabulary production, vocabulary comprehension, and gesture production variables included in this study. 2 Many parents wonder whether their child is normal. They wonder whether he or she is abnormally slow to develop, or so precocious that early celebration is warranted. During their child's first year of life, most parents worry about issues like sleeping, eating, and attainment of motor milestones (especially crawling and walking). During the second year, the focus switches to communication and language. This is true for physicians and other health care professionals

Eleven children with early focal lesions were compared with 70 age-matched controls to assess their performance in repeating nonwords, in learning new words, and in immediate serial recall, a triad of abilities that are believed to share a dependence on serial ordering mechanisms (e.g., Baddeley, Gathercole, & Papagno, 1998; Gupta, in press-a). Results for the experimental group were also compared with other assessments previously reported for the same children by MacWhinney, Feldman, Sacco, and Valds-Prez (2000). The children with brain injury showed substantial impairment relative to controls in the experimental tasks, in contrast with relatively unimpaired performance on measures of vocabulary and nonverbal intelligence. The relationships between word learning, nonword repetition, and immediate serial recall were similar to those observed in several other populations. These results support previous reports that there are persistent processing impairments following early brain injury, despite developmental plasticity. They also suggest that word learning, nonword repetition, and immediate serial recall may be relatively demanding tasks, and that their relationship is a fundamental aspect of the cognitive system.