Abstract
The study examines the influence of the format and features e of tasks employed to assess cognitive abilities. Three experiments investigated the effect of practice on performance differences between performers of these tasks. Two experiments were conducted on a computerized, demanding task, developed to assess attention management and multitask performance. The third experiment examined practice effects in six replications of a five tasks battery, consisting of tasks commonly used in the evaluation of cognitive functions. Significant individual differences were observed in all experiments, within and across tasks. However, practicing differentially affects tasks and components within tasks.
Three types of practice effects on performance were identified: (1) Performance levels did not change and did not benefit from practice in components which mainly draw upon the operation of bottom-up, exogenous attention systems; (2) Practice had strong asymmetric effects on performance when performance required to resolve a conflict between two automatically attended elements. In these tasks, performers with lower initial performance scores benefited more from practice than those with higher initial performance levels. (3) For tasks in which executive control and working memory were called upon but there was no conflict to resolve, significant practice effects were obtained with equal gains for performers differing in initial performance levels.
The important implication of the obtained results is that when a task is developed as test to evaluate a cognitive ability, its format and features may affect first session performance and only clarified with practice. The contribution of format and components are discussed with reference to research on the evaluation of individual differences in cognitive abilities, types of attention demand and working memory requirements.