This book reflects the current pressure to develop useful models and methodologies to study executive behavior: the ability to update information in working memory in order to control selective attention to formulate plans of action and to monitor their efficient execution. Many models are based on the concept of a single "central executive" that manages these functions; others propose a number of independent "working memory systems" that each serve one task or activity but not others. Central problems are the extent to which tests of executive function are reliable and valid measures; the extent to which hypothetical properties of the cognitive system such as "inhibition" or "goal directness" are empirically verifiable constructs; the extent to which particular cognitive functions can be mapped on the particular areas of the prefrontal cortex, and the extent to which changes in cognitive function in old age can be related to loss of integrity of frontal and temporal cortex in normally aging brains.

The book is a collection of essays by distinguished and active researchers who discuss their own recent work on the definition of "executive" of "controlled" behaviors, and on the relation of these behaviors to specific areas of the frontal cortex. They are particularly concerned with logical difficulties that arise in defining these functions that lead, in turn, to methodological difficulties in studying them. In particular they discuss such problems as the low test-re-test reliability of tasks that have been used to define, and explore "executive" behaviors, the limited validity of these tasks in predicting performance deficits, the poor localization of the changes observed with respect to underlying brain function and the relation of performance on these tasks to individual differences in performance on measures of "global" or "general" intellectual ability such as Spearman's (1927) gf. They discuss their own research on the relations between cognitive function and neuropsychology, on changes in executive competence in conditions such as closed head injuries of dementia's that may diffusely affect the whole brain, and on changes in executive function in normal old age.