Watching the infant brain learn words: Effects of vocabulary size and experience

Previous investigations comparing auditory event-related potentials (ERPs) to words whose meanings infants did or did not comprehend, found bilateral differences in brain activity to known versus unknown words in 13-month-old infants, in contrast with unilateral, left hemisphere, differences in activity in 20-month-old infants. We explore two alternative explanations for these findings. Changes in hemispheric specialization may result from a qualitative shift in the way infants process known words between 13 and 20 months. Alternatively, hemispheric specialization may arise from increased familiarity with the individual words tested. We contrasted these two explanations by measuring ERPs from 20-month-old infants with high and low production scores, for novel words they had just learned. A bilateral distribution of ERP differences was observed in both groups of infants, though the difference was larger in the left hemisphere for the high producers. These findings suggest that word familiarity is an important factor in determining the distribution of brain regions involved in word learning. An emerging left hemispheric specialization may reflect increased efficiency in the manner in which infants process familiar and novel words. (c) 2004 Elsevier Inc. All rights reserved.

A multiwave range test for obstacle reconstructions with unknown physical properties

We develop a new multiwave version of the range test for shape reconstruction in inverse scattering theory. The range test [R. Potthast, et al., A ‘range test’ for determining scatterers with unknown physical properties, Inverse Problems 19(3) (2003) 533–547] has originally been proposed to obtain knowledge about an unknown scatterer when the far field pattern for only one plane wave is given. Here, we extend the method to the case of multiple waves and show that the full shape of the unknown scatterer can be reconstructed. We further will clarify the relation between the range test methods, the potential method [A. Kirsch, R. Kress, On an integral equation of the first kind in inverse acoustic scattering, in: Inverse Problems (Oberwolfach, 1986), Internationale Schriftenreihe zur Numerischen Mathematik, vol. 77, Birkhäuser, Basel, 1986, pp. 93–102] and the singular sources method [R. Potthast, Point sources and multipoles in inverse scattering theory, Habilitation Thesis, Göttingen, 1999]. In particular, we propose a new version of the Kirsch–Kress method using the range test and a new approach to the singular sources method based on the range test and potential method. Numerical examples of reconstructions for all four methods are provided.

Infants Can Learn Decontextualized Words Before Their First Birthday

Can infants below age 1 year learn words in one context and understand them in another? To investigate this question, two groups of parents trained infants from age 9 months on 8 categories of common objects. A control group received no training. At 12 months, infants in the experimental groups, but not in the control group, showed comprehension of the words in a new context. It appears that infants under 1 year old can learn words in a decontextualized, as distinct from a context-bound, fashion. Perceptual variability within the to-be-learned categories, and the perceptual similarity between training sets and the novel test items, did not appear to affect this learning.

Transnationalism personified: young returning Trinidadians 'in their own words'

In this paper we consider the nexus existing between returning transnational migrants to Trinidad and Tobago's adaptation experiences, matters pertaining to their transnational life-paths, family and community experiences and their views on transnationalism and return. The research is based on an analysis of the detailed narratives provided by forty informants by means of semi-structured interviews. The informants consisted of nine 'second-generation', seven 'one-and-a-half-generation' and twenty-four 'prolonged sojourner' returning transnational migrants to Trinidad and Tobago. The main conceptual themes that characterise Caribbean transnationalism are presented at the beginning of the paper. Addressing these in the context of Trinidad and Tobago, we present our narrative-based findings under the following headings derived from analysis of our informant's experiences and views: transnational family and life-course issues; transnational community relationships; keeping in touch; transnational mobility and 'home as fixed anchor'; transnational identity; transnational economic and commercial interests; and strategic flexibility.

Beyond words: Aesthetic knowledge and knowing in design

Aesthetic knowledge comes from practitioners understanding the look, feel, smell, taste and sound of things. It is vital to work in many organizational contexts. In this paper, we explore aesthetic knowledge and knowing in organizations through detailed observation of design work in the architectural practice Edward Cullinan Architects. Through our research, we explore aesthetic knowledge in the context of architectural work, we unpack what it is, how it is generated, and how it is applied in design projects, shared between practitioners and developed at the level of the organization. Our analysis suggests that aesthetic knowledge plays an important part in organizational practice, not only as the symbolic context for work, but as an integral part of the work that people do. It suggests that aesthetic reflexivity, which involves an opening up and questioning of what is known, is experienced as part of practice as well as a `time out' from practice.

Discrepancy between parental reports of infants' receptive vocabulary and infants' behaviour in a preferential looking task

Two experiments are described which explore the relationship between parental reports of infants' receptive vocabularies at 1; 6 (Experiment 1a) or 1-3, 1;6 and 1;9 (Experiment 1b) and the comprehension infants demonstrated in a preferential looking task. The instrument used was the Oxford CD1, a British English adaptation of the MacArthur-Bates CD1 (Words & Gestures). Infants were shown pairs of images of familiar objects, either both name-known or both name-unknown according to their parent's responses on the CD1. At all ages, and on both name-known and name-unknown trials, preference for the target image increased significantly from baseline when infants heard the target's label. This discrepancy suggests that parental report underestimates infants' word knowledge.

Visual motion interferes with lexical decision on motion words

Embodied theories of cognition propose that neural substrates used in experiencing the referent of a word, for example perceiving upward motion, should be engaged in weaker form when that word, for example ‘rise’, is comprehended. Motivated by the finding that the perception of irrelevant background motion at near-threshold, but not supra-threshold, levels interferes with task execution, we assessed whether interference from near-threshold background motion was modulated by its congruence with the meaning of words (semantic content) when participants completed a lexical decision task (deciding if a string of letters is a real word or not). Reaction times for motion words, such as ‘rise’ or ‘fall’, were slower when the direction of visual motion and the ‘motion’ of the word were incongruent — but only when the visual motion was at nearthreshold levels. When motion was supra-threshold, the distribution of error rates, not reaction times, implicated low-level motion processing in the semantic processing of motion words. As the perception of near-threshold signals is not likely to be influenced by strategies, our results support a close contact between semantic information and perceptual systems.

Neurofuzzy control using Kalman filtering state feedback with coloured noise for unknown non-linear processes

This paper presents a controller design scheme for a priori unknown non-linear dynamical processes that are identified via an operating point neurofuzzy system from process data. Based on a neurofuzzy design and model construction algorithm (NeuDec) for a non-linear dynamical process, a neurofuzzy state-space model of controllable form is initially constructed. The control scheme based on closed-loop pole assignment is then utilized to ensure the time invariance and linearization of the state equations so that the system stability can be guaranteed under some mild assumptions, even in the presence of modelling error. The proposed approach requires a known state vector for the application of pole assignment state feedback. For this purpose, a generalized Kalman filtering algorithm with coloured noise is developed on the basis of the neurofuzzy state-space model to obtain an optimal state vector estimation. The derived controller is applied in typical output tracking problems by minimizing the tracking error. Simulation examples are included to demonstrate the operation and effectiveness of the new approach.