The role of placekeeping ability in fluid intelligence.

The question of what underlies individual differences in general intelligence has never been satisfactorily answered. The purpose of this research was to investigate the role of an executive function that we term placekeeping ability-the ability to perform the steps of a complex task in a prescribed order without skipping or repeating steps. Participants completed a newly developed test of placekeeping ability, called the UNRAVEL task. The measure of placekeeping ability from this task (error rate) predicted a measure of fluid intelligence (Raven's Advanced Progressive Matrices score), above and beyond measures of working memory capacity, task switching, and multitasking. An existing model of Raven's performance suggests that placekeeping ability supports the systematic exploration of hypotheses under problem-solving conditions.