The time taken to react voluntarily to a stimulus is far longer than can be accounted for by ordinary processes of nerve conduction and synaptic delay, and varies unpredictably from trial to trial. Though random, the distribution of reaction times usually follows a relatively simple law, which in turn can be explained by the LATER model, in which a decision signal, representing belief in the existence of the target, rises in response to incoming sensory evidence from an initial value to (...) a criterion level at which action is initiated. But the rate of rise fluctuates randomly from trial, to an extent that cannot be explained by sensory noise at the input. These conclusions, confirmed by recording from neurons in the frontal eye fields, suggest that the randomness of reaction time is due to a deliberate, gratuitous, neural process which confers certain biological advantages as well as having implications for general ideas about the nature of ‘free will'. (shrink)

Ten leading scholars provide exacting research results and a reliable and accessible introduction to the new field of optimality theoretic pragmatics. The book includes a general introduction that overviews the foundations of this new research paradigm. The book is intended to satisfy the needs of students and professional researchers interested in pragmatics and optimality theory, and will be of particular interest to those exploring the interfaces of formal pragmatics with grammar, semantics, philosophy of language, information theory and cognitive psychology.

In list-method directed forgetting, reexposure to forgotten List 1 items has been shown to reduce directed forgetting. proposed that reexposure to a few List 1 items only during a direct test of memory reinstates the entire List 1 episode. In the present experiments, part-list reexposure in the context of indirect as well as direct memory tests reduced directed forgetting. Directed forgetting was reduced when 50% or more of the items were reexposed, and was intact when only 25% were reexposed. Furthermore, (...) part-list reexposure appeared to reinstate only reexposed items-not the entire List 1 episode. (shrink)

Properties sometimes attributed to the “particle” aspect of a neutron, e.g., mass and magnetic moment, cannot straightforwardly be regarded in the Bohm interpretation of quantum mechanics as localized at the hypothetical position of the particle. This is shown by examining a series of effects in neutron interferometry. A related thought-experiment also provides a variation of a recent demonstration that which-way detectors can appear to behave anomolously in the Bohm theory.

In 1826 Americans witnessed the spectacle of President John Quincy Adams and Vice-President John C. Calhoun taking to the press to debate the nature of power and liberty under the pseudonyms "Patrick Henry" and "Onslow". In the course of this exchange some of the most salient issues within American politics and liberty are debated, including the nature of political order, democracy, and the diffusion of political power.

A simple model for the description of atomic and ionic species with spectra exhibiting a quantum defect is solved using the Lie algebra su(1, 1). The quantum defect of bound states is related to the phase shift of scattering states. The resonances are discussed in terms of the nonunitary representations of this algebra.