Ageing and word processing competence: compensation or compilation?

Composition and compilation were examined as two alternative hypotheses relating to 'cognitive competence' in older adults. Techniques of molar equivalence-molecular decomposition (ME-MD) and molecular equivalence-molar analysis (ME-MA) were used to investigate performance of experienced (over 100 hours) younger (18-30 years) and older (45-66 years) adults on a word processing task, requiring insertion and deletion of words from passages of text. There was some indication that typing skill may form the basis of a compensatory mechanism. However, differences between 'good' and 'poor' performers in the older sample supported the position that high levels of complex task skill in older adults are associated with the possession (possibly through maintenance) of high levels of basic cognitive capacities, and are not related to the integration of molecular task components.

Task allocation and the balancing of task demands in the multi-man-machine system--some case studies.

Various forms of team organisation are described. These are based on the concepts of vertical and horizontal structure. Task factors of complexity and organisation are introduced and their relationships with various forms of multiman-machine system are discussed. Experimental work is briefly described and then two case study analyses of operational systems are presented. The first, an examination of airport air traffic control, illustrates how a multiman system can be reorganised to yield a more balanced distribution of task demands. The second, a study of an ambulance control room, shows the implications for team organisation of a shared computer data-base. These case studies demonstrate that the concepts developed in the laboratory context can be applied to operational multiman-machine systems.

Part and whole practice for a tracking task: effects of task variables and amount of practice.

Whole and part methods were compared to test Naylor's hypothesis that, in a task of high organization, whole methods should become more efficient with increased complexity. Task complexity was varied by having two levels of display-control relationship. The part versus whole comparisons were made in two conditions, one requiring early changeover, the other later changeover to whole task practice. In the early changeover condition no significant differences were found between part and whole methods at either level of complexity. With later changeover, on the other hand, pure part training was inferior to whole training in the high complexity task. This result was present only in the first block of whole practice. No differences were found with the low complexity task. The experiment offers limited support for Naylor's hypothesis. The predicted superiority of the whole method in the high complexity task was only short lived and disappeared with further practice. Furthermore, this prediction was upheld only with later changeover to whole task performance.