New Developments in Understanding Skilled Performance

ABSTRACT— Skilled performance, whether it involves rapid and accurate motor movements (such as playing a video game or using a scalpel in the operating room) or a high degree of domain knowledge (such as finding a small tumor in an X-ray or writing a journal article) typically involves learning and practice over an extended period of time. In light of recent theory and empirical research, I consider two enduring issues associated with skill acquisition: whether individuals become more alike in performance or more different over the course of skill acquisition, and what the determinants of individual differences in skilled performance are. Two broad classes of tasks are considered: tasks that involve speed and accuracy of motor movements and tasks that primarily involve domain knowledge. Issues of practice, ability, and other determinants of skilled performance such as gender and aging are discussed.     

The Signal-Cognition interface: Interactions between degraded auditory signals and cognitive processes

A hearing loss leads to problems with speech perception; this is exacerbated when competing noise is present. The speech signal is recognized by the cognitive system of the listener; noise and distortion tax the cognitive system when interpreting it. The auditory system must interact with the cognitive system for optimal signal decoding. This article discusses this interaction between the signal and cognitive system based on two models: an auditory model describing signal transmission and degeneration due to a hearing loss and a cognitive model for Ease of Language Understanding. The signal distortion depends on the specifics of the hearing impairment and thus differently distorted signals can affect the cognitive system in different ways. Consequently, the severity of a hearing loss may not only depend on the lesion itself but also on the cognitive recourses required to interpret the signal.     

Cognition and hearing aids

The perceptual information transmitted from a damaged cochlea to the brain is more poorly specified than information from an intact cochlea and requires more processing in working memory before language content can be decoded. In addition to making sounds audible, current hearing aids include several technologies that are intended to facilitate language understanding for persons with hearing impairment in challenging listening situations. These include directional microphones, noise reduction, and fast-acting amplitude compression systems. However, the processed signal itself may challenge listening to the extent that with specific types of technology, and in certain listening situations, individual differences in cognitive processing resources may determine listening success. Here, current and developing digital hearing aid signal processing schemes are reviewed in the light of individual working memory (WM) differences. It is argued that signal processing designed to improve speech understanding may have both positive and negative consequences, and that these may depend on individual WM capacity.     

Cognition and aided speech recognition in noise: Specific role for cognitive factors following nine-week experience with adjusted compression settings in hearing aids

The working memory model for Ease of Language Understanding (ELU) proposes that language understanding under taxing conditions is related to explicit cognitive capacity. We refer to this as the mismatch hypothesis, since phonological representations based on the processing of speech under established conditions may not be accessed so readily when input conditions change and a match becomes problematic. Then, cognitive capacity requirements may differ from those used for processing speech hitherto. In the present study, we tested this hypothesis by investigating the relationship between aided speech recognition in noise and cognitive capacity in experienced hearing aid users when there was either a match or mismatch between processed speech input and established phonological representations. The settings in the existing digital hearing aids of the participants were adjusted to one of two different compression settings which processed the speech signal in qualitatively different ways ("fast" or "slow"). Testing took place after a 9-week period of experience with the new setting. Speech recognition was tested under different noise conditions and with match or mismatch (i.e. alternative compression setting) manipulations of the input signal. Individual cognitive capacity was measured using a reading span test and a letter monitoring test. Reading span, a reliable measure of explicit cognitive capacity, predicted speech recognition performance under mismatch conditions when processed input was incongruent with recently established phonological representations, due to the specific hearing aid setting. Cognitive measures were not main predictors of performance under match conditions. These findings are in line with the ELU model.     

THE EFFECTS OF DIFFERENTIAL REINFORCEMENT OF UNPROMPTED RESPONDING ON THE SKILL ACQUISITION OF CHILDREN WITH AUTISM

The recommendation to reserve the most potent reinforcers for unprompted responses during acquisition programming has little published empirical support for its purported benefits (e.g., rapid acquisition, decreased errors, and decreased prompt dependence). The purpose of the current investigation was to compare the delivery of high‐quality reinforcers exclusively following unprompted responses (differential reinforcement) with the delivery of high‐quality reinforcers following both prompted and unprompted responses (nondifferential reinforcement) on the skill acquisition of 2 children with autism. Results indicated that both were effective teaching procedures, although the differential reinforcement procedure was more reliable in producing skill acquisition. These preliminary findings suggest that the differential reinforcement of unprompted responses may be the most appropriate default approach to teaching children with autism.     

Priorities of Global Justice

One-third of all human deaths are due to poverty-related causes, to malnutrition and to diseases that can be prevented or cured cheaply. Yet our politicians, academics, and mass media show little concern for how such poverty might be reduced. They are more interested in possible military interventions to stop human rights violations in developing countries, even though such interventions – at best – produce smaller benefits at greater cost. This Western priority may be rooted in self-interest. But it engenders, and is sustained by, a deeply flawed moral presentation of global economic cooperation. The new global economic order we impose aggravates global inequality and reproduces severe poverty on a massive scale. On any plausible understanding of our moral values, the prevention of such poverty is our foremost responsibility.     

Global Distributive Justice

The paper discusses the problem of global distributive justice. It proposes to distinguish between principles for the domestic and for the global or intersocietal distribution of wealth. It is argued that there may be a plurality of partly diverging domestic conceptions of distributive justice, not all of which need to be liberal egalitarian conceptions. It is maintained, however, that principles regulating the intersocietal distribution of wealth have to be egalitarian principles. This claim is defended against Rawls's argument in The Law of Peoples that egalitarian principles of distributive justice should not be applied globally. Moreover, it is explained in detail, why Rawls's "duty of assistance to burdened societies" cannot be an appropriate substitute for a global principle of distributive justice.     

Manual dexterity in the gorilla: bimanual and digit role differentiation in a natural task

The manipulative actions of mountain gorillas Gorilla g. beringei were examined in the context of foraging on hard-to-process plant foods in the field, in particular those used in tackling thistle Carduus nyassanus. A repertoire of 72 functionally distinct manipulative actions was recorded. Many of these actions were used in several variants of grip, finger(s) and movement path, both by different individuals and by the same individual at different times. The repertoire appears somewhat greater than that observed in comparable studies of monkeys, but a far more striking difference is found in the use of differentiated actions in concert. Mountain gorillas routinely and frequently deal with problems that involve: (1) bimanual role differentiation, with the two hands taking different roles but synchronized in time and space, and (2) digit role differentiation, with independent control of parts of the same hand used for separate purposes at the same time. The independent control that allows these abilities, so crucial to human manual constructional ability, is apparently general in African great apes. Role differentiation, between and within the hand, is evidently a primitive characteristic in the human arsenal of skills. Accepted after revision: 6 April 2001 Electronic Publication     

THE EFFECTS OF FORM TRAINING ON FOUL‐SHOOTING PERFORMANCE IN MEMBERS OF A WOMEN'S COLLEGE BASKETBALL TEAM

The effects of instruction and feedback in proper form on foul‐shooting performance was evaluated in 3 players of a women's NCAA Division II college basketball team. Players showed an increase in percentage of shots made and in correct form compared to baseline shooting without instruction or feedback. All players reached criterion within seven training sessions. The results suggest that training proper form is an effective strategy for improving foul‐shooting performance.