'Recast' in a new light: insights for practice from typical language studies

This article reviews the nature and function of RECASTS, a well-documented way of responding to young children. Recasts have featured in intervention programmes for children with language delay (LD), but with mixed success. The aim of the current review is to provide a theoretically-motivated account of just those recasts that are likely to benefit LD children. To this end, the Contrast theory of corrective input is invoked, where the focus is on adult models that are directly contingent on child errors (Saxton, 1997). Both theoretical and empirical evidence suggests that this kind of input can facilitate the acquisition of adult-like grammatical competenc

What's in a name? Coming to terms with the child's linguistic environment

This article reviews the proliferation of terms that have been coined to denote the language environment of the young child. It is argued that terms are often deployed by researchers without due consideration of their appropriateness for particular empirical studies. It is further suggested that just three of the dozen or more available terms meet the needs of child language researchers in most instances: Child Directed Speech, Infant Directed Speech and exposure language. The phenomena denoted by these terms are then considered. The term register is generally borrowed for this purpose from sociolinguistics. However, close inspection of this concept reveals that the notion of register needs to be constrained, in specified ways, in order to be of any real value within the field of child language research

Counting-on, trading and partitioning: effects of training and prior knowledge on performance on Base-10 tasks

Factors affecting performance on Base-10 tasks were investigated in a series of four studies with a total of 453 children aged five to seven years. Training in counting-on was found to enhance child performance on Base-10 tasks (Studies 2, 3, and 4), while prior knowledge of counting-on (Study 1), trading (Studies 1 and 3) and partitioning (Studies 1 and 4) were associated with enhanced Base-10 performance. It emerged that procedural knowledge of counting-on, trading and partitioning can lead to improvements in procedural knowledge of the Base-10 system. The findings lend support to the model of iterative development of conceptual and procedural knowledge advanced by Rittle-Johnson, Siegler and Alibali (2001)

Negative input for grammatical errors: effects after a lag of 12 weeks

Effects of negative input for 13 categories of grammatical error were assessed in a longitudinal study of naturalistic adult-child discourse. Two-hour samples of conversational interaction were obtained at two points in time, separated by a lag of 12 weeks, for 12 children (mean age 2;0 at the start). The data were interpreted within the framework offered by Saxton’s (1997; 2000) contrast theory of negative input. Corrective input was associated with subsequent improvements in the grammaticality of child speech for three of the target structures. No effects were found for two forms of positive input: non-contingent models, where the adult produces target structures in non-error-contingent contexts; and contingent models, where grammatical forms follow grammatical child usages. The findings lend support to the view that, in some cases at least, the structure of adult-child discourse yields information on the bounds of grammaticality for the language-learning child

The prompt hypothesis: clarification requests as corrective input for grammatical errors

The potential of clarification questions (CQs) to act as a form of corrective input for young children's grammatical errors was examined. Corrective responses were operationalized as those occasions when child speech shifted from erroneous to correct (E -> C) contingent on a clarification question. It was predicted that E -> C sequences would prevail over shifts in the opposite direction (C -> E), as can occur in the case of nonerror-contingent CQs. This prediction was tested via a standard intervention paradigm, whereby every 60s a sequence of two clarification requests (either specific or general) was introduced into conversation with a total of 45 2- and 4-year-old children. For 10 categories of grammatical structure, E -> C sequences predominated over their C -> E counterparts, with levels of E -> C shifts increasing after two clarification questions. Children were also more reluctant to repeat erroneous forms than their correct counterparts, following the intervention of CQs. The findings provide support for Saxton's prompt hypothesis, which predicts that error-contingent CQs bear the potential to cue recall of previously acquired grammatical forms

Negative evidence and negative feedback: immediate effects on the grammaticality of child speech

Until recently, a long-standing assumption in the field of child language acquisition research was that parents do not correct the grammatical errors of their children. While consensus now exists that potentially corrective responses are often supplied, controversy persists as to whether the child can identify and exploit such information in practice. To address these issues, this study adopts the contrast theory of negative input as a framework for analysis (Saxton 1995). In this theory, two distinct kinds of corrective input are identified, termed negative evidence and negative feedback, respectively. The corrective potential of each category was investigated by examining the immediate effects of each on the grammaticality of child speech. A longitudinal corpus of naturalistic data (49 hours) from a single child were analysed with respect to 11 grammatical categories. The effects of negative input were compared with two non-corrective sources of input, namely positive input and adult move-ons. It was found that grammatical forms were more frequent in child speech following negative evidence and negative feedback than either of the two non-corrective sources of input. In light of these, and related, findings, it is argued that corrective input may well prove important in explanations for how the child eventually retreats from error to attain a mature system of grammar

Constraints on Primary Production in Lake Erie

The Laurentian Great Lake, Lake Erie is an invaluable global resource and its watershed is home to over 11 million people. The pressures placed on the lake because of this high population caused Lake Erie to experience numerous environmental problems, including seasonal hypoxia and harmful algal blooms. While these topics have been widely studied in Lake Erie for over 40 years a more nuanced understanding of the interaction between phytoplankton and nutrient is needed to properly address the problems continuing to face the lake. In this study we combine classical limnological and cell growth experiments with modern molecular biological techniques and microscopy to more completely describe the aquatic microbial ecology of the lake. We used an oxalate rinse technique to examine the surface absorbed P pool of the toxic cyanobacterium Microcystis aeruginosa grown under a range of P conditions, as well as the general Lake Erie plankton assemblage. Our results suggest that while Microcystis is plastic in its cellular P needs, the ratio of intracellular to extracellular P remains stable across growth conditions. We describe the effect of the phosphonate herbicide glyphosate on the Lake Erie phytoplankton community using laboratory cell growth studies, field microcosm experiments and PCR amplification of a gene implicated in the breakdown of this compound from the environment. Results from these experiments suggest that the presence of glyphosate can affect community structure in multiple ways and may explain areas of unexplained phytoplankton diversity in coastal areas of Lake Erie. We also show heterotrophic bacteria are likely critical to the breakdown of glyphosate and further illustrate that understanding the context of the larger microbial community is critical to understanding the ecology of the constituent members of the community. Finally, we investigate the activity of the phytoplankton community in winter months with a focus on diatoms abundant in Lake Erie under the ice. We show these diatoms are active and that the winter bloom is a likely source of carbon important to seasonal hypoxia formation. Together, these studies significantly enrich our understanding of how phytoplankton influence important ecological processes in Lake Erie

Basic calculation proficiency and mathematics achievement in elementary school children

The relation between skill in simple addition and subtraction and more general math achievement in elementary school is well established but not understood. Both the intrinsic importance of skill in simple calculation for math and the influence of conceptual knowledge and cognitive factors (working memory, processing speed, oral language) on simple calculation and math are plausible. The authors investigated the development of basic calculation fluency and its relations to math achievement and other factors by tracking a group of 259 United Kingdom English children from second to third grade. In both grades the group did not retrieve the solutions to most problems, but their math achievement was typical. Improvement in basic calculation proficiency was partially predicted by conceptual knowledge and cognitive factors. These factors only partially mediated the relation between basic calculation and math achievement. The relation between reading and math was wholly mediated by number measures and cognitive factors

'No Negative Evidence': What's the Problem?

Proceedings of the Twenty-Second Annual Meeting of the Berkeley Linguistics Society: General Session and Parasession on The Role of Learnability in Grammatical Theory (1996

Effect of age on cutaneous vasomotor responses during local skin heating

This study examined the effect of ageing on the low-frequency oscillations (vasomotion) of skin blood flow in response to local heating (LH). Skin blood flow was assessed by laser-Doppler flowmetry on the forearm at rest (33 °C) and in response to LH of the skin to both 42 °C and 44 °C in 14 young (24 ± 1 years) and 14 older (64 ± 1 years) participants. Vasomotion was analyzed using a wavelet transform to investigate power of the frequency intervals associated with endothelial, neural, myogenic, respiratory, and cardiac activities of the laser-Doppler signal. Laser-Doppler flux increased in both groups with LH (both d > 1.8, p 1.2, p 0.9, p 0.7), myogenic (d = 0.3, p > 0.7), respiratory (d = 0.4, p > 0.6), and cardiac (d = 0.1, p > 0.7) frequency intervals. These data indicate that LH increases cutaneous endothelial and myogenic activity, while decreasing neural activity. Furthermore, ageing reduces the increase in cutaneous endothelial activity in response to LH