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-

We investigated grapheme--colour synaesthesia and found that: (1) The induced colours led to perceptual grouping and pop-out, (2) a grapheme rendered invisible through `crowding' or lateral masking induced synaesthetic colours --- a form of blindsight --- and (3) peripherally presented graphemes did not induce colours even when they were clearly visible. Taken collectively, these and other experiments prove conclusively that synaesthesia is a genuine perceptual phenomenon, not an effect based on memory associations from childhood or on vague metaphorical speech. We identify different subtypes of number--colour synaesthesia and propose that they are caused by hyperconnectivity between colour and number areas at different stages in processing; lower synaesthetes may have cross-wiring (or cross-activation) within the fusiform gyrus, whereas higher synaesthetes may have cross-activation in the angular gyrus. This hyperconnectivity might be caused by a genetic mutation that causes defective pruning of connections between brain maps. The mutation may further be expressed selectively (due to transcription factors) in the fusiform or angular gyri, and this may explain the existence of different forms of synaesthesia. If expressed very diffusely, there may be extensive cross-wiring between brain regions that represent abstract concepts, which would explain the link between creativity, metaphor and synaesthesia (and the higher incidence of synaesthesia among artists and poets). Also, hyperconnectivity between the sensory cortex and amygdala would explain the heightened aversion synaesthetes experience when seeing numbers printed in the `wrong' colour. Lastly, kindling (induced hyperconnectivity in the temporal lobes of temporal lobe epilepsy [TLE] patients) may explain the purp...

This paper presents a case study of 3- to 9-year-old children's concepts of size, weight, density, matter, and material kind. Our goal was to examine two claims: (1) that individual concepts undergo differentiation during development; and (2) that young children's concepts are embedded in theory-like structures. To make progress on the first issue, we needed to specify in representational terms what an undifferentiated concept is like and in what sense this undifferentiated concept is a parent of the more differentiated concepts. Our strategy was to use a model of conceptual differentiation suggested by the history of science to guide our search for evidence. In this model, undifferentiated concepts, like differentiated concepts, can be analyzed in terms of their component properties, features, or dimensions. The key difference is that an undifferentiated concept unites certain components which will subsequently be analyzed as components of distinct concepts, and that the undifferentiated concept is embedded in a different theoretical structure from the differentiated concepts. In our study, the same group of 78 children (18 3-year-olds, 18 4-year-olds, 18 5-year-olds, 12 6-7-year-olds, and 12 8-9-year-olds) were given a range of tasks probing their understanding of size, weight, and density; a

In most research on concept formation within machine learning and cognitive psychology, the features from which concepts are built are assumed to be provided as elementary vocabulary. In this paper, we argue that this is an unnecessarily limited paradigm within which to examine concept formation. Based on evidence from psychology and machine learning, we contend that a principled account of the origin of features can only be given with a grounded model of concept formation, i.e., with a model that incorporates direct access to the world via sensors and manipulators. We discuss the domain of process control as a suitable framework for research into such models, and present a first approach to the problem of developing elementary vocabularies from perceptual sensor data. 1

Abstract. The human brain has evolved the capacity for language not only through specific mechanisms of routinized articulation of speech patterns, but through general mechanisms of adaptive memory organization. As shown by amnesic syndromes in humans and animals, the consolidation of memory requires neural traffic between localized neocortical networks, specialized for sensory or motor articulation, and the more diffuse, densely-interconnected limbic networks at the core of the brain. The connectivity of limbic networks allows not only the integration of widespread cortical regions, but the recruitment of subcortical motivational systems. A cognitive representation, such as supports the understanding of a word, is thus multileveled, with four or five discrete network levels in the pathway linking limbic (visceral) with neocortical (sensorimotor articulation) representations. Through their influences on subcortical arousal systems, the limbic networks provide motivational control over the consolidation process. Through reentrant corticolimbic traffic, language appears to be articulated in neocortical networks through a microdevelopmental process that begins in the prelinguistic, syncretic, postural-affective matrix of felt emotional significance represented at the limbic core of the brain. In its fundamental architecture, meaning is thus embodied. On the other hand, conscious realization of meaning may require the differentiation of specific form out of the syncretic paralimbic matrix, and this realization

Infants' developing causal expectations for the outcome of a simple tool-use event from ages 8 to 12 months were investigated. Causal expectations were studied by comparing infants' developing tool-use actions (i.e., as tool-use agents) with their developing perceptual reactions (i.e., as tool-use observers) to possible and impossible tool-use events. In Experiment 1, tool-use actions were studied by presenting infants, ages 8 and 12 months, with tool-use object-retrieval problems. In Experiment 2, a second age-matched sample of infants watched a comparable series of possible and impossible tool-use events in which a tool was used to retrieve a goalobject. Two core related findings were made. First, infants' causal action and causal perception develop in parallel. In both action and perception, supporting tool-use develops before surrounding tool-use. Second, infants' tool-use action develops before their causal perception of comparable tool-use events. The findings support the constru...

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The publication of this report was supported under the Educational Research and Development Center Program (R117G1O036 for the National Center for the Study of Writing) as administered by the Office of Educational Research and Improvement, U.S. Department of Education. The findings and opinions expressed in this report do not reflect the position or policies of the Office of Educational Research and Improvement or the U.S. Department of Education.

readings of earlier drafts. Correspondence concerning this article should be addressed to Jay A.

The publication of this report was supported under the Educational Research and Development Center Program (R117G1O036 for the National Center for the Study of Writing) as administered by the Office of Educational Research and Improvement, U.S. Department of Education. The findings and opinions expressed in this report do not reflect the position or policies of the Office of Educational Research and Improvement or the U.S. Department of Education.