Language-specific listening

Languages differ in their phonological structure and physcholinguists have begun to explore the conseqence, of this fact for speech perception. We review research documenting that listeners attune their perceptual processes finaly to exploit the phonological regularities of their nativ language. As a consequence, these perceptual process are fill-adapted to listening to languages that do not display such, regularities. Thus, not only do late language-learners have trouble speaking a second language, also they do not hear it as native speakers do; worse, they apply their native language listening prosedures which may actually interfere with successful processing of the non-native input. We also present data from studies on infants showing that the initial attuning occurs early in life; very yong infants are sensitive to the relevant phonological regularities which distinguish different languages, and quickly distinguish the native language of their environment from languages with different regularities.     

Cortical maps for hearing and egocentric selection for self-organization

The auditory cortex of the mustached bat shows complex multiple frequency maps, because cortical neurons in several areas are tuned to particular combinations of signal elements. Different types of combination-sensitive neurons form computational maps in which information-bearing parameters for echolocation (biosonar) are represented systematically. Neuronal response properties and multiple-frequency and computational maps were considered to be created solely by divergent-convergent interactions of neurons in the 'ascending' system. However, we have found that the 'corticofugal' system also plays an important role. Neurons in an iso-best frequency (or echo delay) 'minicolumn' of the auditory cortex augment the auditory responses of subcortical neurons tuned to that frequency (or echo delay) and sharpen their tuning. At the same time, they reduce the response and shift the tuning of subcortical neurons tuned to other frequencies (or echo delays) away from the best frequency (or delay) of the cortical neurons. Cortical neurons mediate a highly focused positive feedback, incorporated with widespread lateral inhibition, via corticofugal projections. This 'egocentric selection' is expected to play an important role in self-organizing the central auditory system.     

环境伦理学

一、导论面对“环境危机”,环境哲学家们有一种相当普遍的共识,即应该从伦理学的角度来考察环境问题。他们一致认为,环境问题是重要的,但它在过去没有得到足够的重视。同样,他们也一致认为,在我们处理环境问题时,伦理学应起到更大的作用。然而,也有不一致的地方,即环境伦理学是由什么组成的,怎样才能实现它,在什么程度上实现它是理想的。本文考察当个环境伦理学的关键问题。价值观和对环境及为环境所采取的行动深深地被我们对环境的观察与理解影响着。因此,本文一开始叙述了在过去的一个世纪里,在环境问题上,科学对环境问题的…     

Children's Memory for Locations Visited: Importance of Movement and Choice

In 2 experiments, the effect of active or passive mobility and active or passive choice experiences on children's memory for locations visited while retrieving puzzle pieces hidden in a large room were examined. In the first experiment, fifty-two 6- and 7-year-old children were randomly assigned to 1 of 4 training conditions: active choice-active movement, active choice-passive movement, passive choice-active movement, and passive choice-passive movement. After 3 training trials, all children were tested in the active choice-active movement condition. A 2 (movement) x 2 (choice) factorial multivariate analysis of variance revealed a significant main effect for movement. Children who had moved actively to find the puzzle pieces in the training trials had (a) a greater percentage correct, (b) more correct visits between errors, and (c) a later visit of first error than children who had been passively pushed in a wheelchair. Making active choices in training did not significantly affect performance. A second experiment used identical procedures but tested 32 children with mobility dif-difficulties who regularly used a wheelchair because of either cerebral palsy or spina bifida. Children from this group who moved actively during training to retrieve the puzzle pieces also performed better on testing. Implications of the results for children with disabilities and for developmental theory are discussed.     

Age Changes in Interlimb Coupling and the Development of Bimanual Coordination

Changes in interlimb coupling, and their role in the development of bimanual coordination, were studied longitudinally in 6- to 12-month-old infants (N = 6). Infants were observed while they were reaching for simple objects of 2 different sizes. Their use of a uni-versus bimanual strategy for reaching as well as the coupling of their bimanual movements were compared; progress in bimanual coordination of complementary movements was evaluated on 8 different bimanual tasks. The bimanual tasks involved an asymmetrical cooperation between the 2 hands. Although spatiotemporal coupling of bimanual reaching movements did not decrease during the age period studied, infants around 7 months of age used their 2 hands infrequently for reaching. Occurrences of bimanual reaching were particularly low at the session preceding the first bimanual success at a bimanual task. This suggests that the temporal coincidence between greater independence of the 2 hands and progress in bimanual coordination of complementary movements acts in 2 directions: Infants may be more at ease when using their 2 hands in differentiated patterns as the hands move less in synchrony, but, in turn, they may be less likely to move their hands in synchrony as the anticipate mirror manipulations of the object less. The frequency of bimanual reaches increased toward the end of the 1st year. This might have been caused by an increase in the repertoire of bimanual asymmetrical object manipulations and by the fact that the development of bimanual coordination allows infants to manipulate objects with complementary movements even after a bimanual approach toward the object.     

Schedule interactions involving punishment with pigeons and humans

The principal aim of the present experiments was to assess whether punishment increased or decreased the rate of unpunished behavior (contrast and induction, respectively) for which reinforcement rate was held constant, with physical and nonphysical punishers (electric shock and response cost), pigeon and human subjects, signaled and unsignaled components (multiple and mixed schedules), and the presence or absence of a blackout period between components. Across the three experiments there were 20 punishment conditions. Induction was found in nine of those, less consistent response-rate reduction was found in three, contrast was found in four, and in four there was no change in responding from conditions without punishment. Contrast occurred consistently only with multiple schedules during the first exposure to electric-shock punishment. Induction and no change, however, were found with every combination of the independent variables studied. Four conclusions regarding the interactions between punished and unpunished responding emerged from the present results: (a) Both contrast and induction occurred with the reinforcement rate held constant and a blackout between components, (b) induction was more common than contrast, (c) contrast occurred only in the presence of a stimulus different from that correlated with the punisher, and (d) contrast diminished with prolonged exposure to punishment. None of the current theoretical accounts of punishment contrast can explain the present results.