Why your "head is in the clouds" during thinking: The relationship between cognition and upper space

Higher-order cognition in humans has not generally been viewed as closely entwined with the brain mechanisms mediating more basic perceptual-motor interactions in 3-D space. However, recent findings suggest that perceptual and oculomotor mechanisms that are biased toward the upper field (which disproportionately represents radially distant space) are activated during complex mental operations, ranging from semantic processing to mental arithmetic and memory search. The particularly close affinity with upward conjugate eye deviations-further confirmed in a study of 24 schoolchildren who responded to various mental questions and demands-suggests that active, abstract thinking in humans may have expropriated the focal-extra persona I brain systems involved in saccadic exploration of the distant environment in other primates. (C) 2004 Elsevier B.V. All rights reserved.