The mind's eye, looking inward? In search of executive control in internal attention shifting.
In studies of mental counting, participants are faster to increment a count that was just incremented (no-switch trial) than to increment a different count (switch trial). Investigators have attributed the effect to a shift in the internal focus of attention on switch trials. Here we report evidence for other bottom-up and top-down contributions. Two stimuli were mapped to each of two counts. The no-switch facilitation was greater when stimuli repeated than when they were different. Event-related potential (ERP) activity associated with repetitions was anterior to that associated with switching. Runs of no-switch trials elicited faster responses and frontal ERP activity. Runs of switches and large counts both elicited slow responses and reduced P300 amplitudes. Bottom-up processes may include priming on no-switch trials and conflict on switch trials. Top-down processes may control conflict, subvocal rehearsal, and the contents of working memory.
Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109-1109, USA. wgehring@umich.edu
William J
WJ
Gehring
Richard L
RL
Bryck
John
J
Jonides
Roger L
RL
Albin
David
D
Badre
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D003463:Cues; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005260:Female; D006801:Humans; D007092:Imagination / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology