Category-specific impairments of object recognition and naming are among the most intriguing disorders in neuropsychology, affecting the retrieval of knowledge about either living or nonliving things. They can give us insight into the nature of our representations of objects: Have we evolved different neural systems for recognizing different categories of object? What kinds of knowledge are important for recognizing particular objects? How does visual similarity within a category influence object recognition and representation? What is the nature of our semantic (...) knowledge about different objects? We review the evidence on category-specific impairments, arguing that deficits even for one class of object (e.g., living things) cannot be accounted for in terms of a single information processing disorder across all patients; problems arise at contrasting loci in different patients. The same apparent pattern of impairment can be produced by damage to different loci. According to a new processing framework for object recognition and naming, the hierarchical interactive theory (HIT), we have a hierarchy of highly interactive stored representations. HIT explains the variety of patients in terms of (1) lesions at different levels of processing and (2) different forms of stored knowledge used both for particular tasks and for particular categories of object. Key Words: category-specific deficits; functional imaging; hierarchical models; interactive activation models; neuropsychology; object recognition; perceptual and functional knowledge. (shrink)
We summarise and respond to the main points made by the commentators on our target article, which concern: (1) whether structural similarity can play a causal role in normal object identification and in neuropsychological deficits for living things, (2) the nature of our structural knowledge of the world, (3) the relations between sensory and functional knowledge of objects, and the nature of our functional knowledge about living things, (4) whether we need to posit a “core” semantic system, (5) arguments that (...) can be marshalled from evidence on functional imaging, (6) the causal mechanisms by which category differences can emerge in object representations, and (7) the nature of our knowledge about categories other than living and nonliving things. We also highlight points raised in our article that seem to be accepted. (shrink)
Transcranial magnetic stimulation, EEG, and behavioral studies by our group implicate spurious activation of speech perception neurocircuitry in the genesis of auditory hallucinations in schizophrenia. The neurobiological basis of these abnormalities remains uncertain, however. We review our ongoing studies, which suggest that altered cortical coupling underlies speech processing in schizophrenia and is expressed via disrupted gamma resonances and impaired corollary discharge function of self-generated verbal thought.
The papers in this volume explore the nature of intention and intentional action against the background of G.E.M. Anscombe’s 'Intention' (2nd ed., 1963; repr. Cambridge: Harvard University Press, 2000). Taken together, they demonstrate why the position that Michael Thompson has called Anscombe’s “analytical Aristotelianism” deserves to be regarded as a serious alternative to the analytical Humeanism (to coin a label) that has prevailed in Anglophone philosophy of mind and action since the work of Donald Davidson.