Are spatial selection and identity extraction separable when attention is controlled endogenously?
Visual search for a target involves two processes: spatial selection and identity extraction. Ghorashi, Enns, and Di Lollo (2008) found these processes to be independent and surmised that they were carried out along distinct visual pathways: dorsal and ventral, respectively. The two experiments that are described in the present article evaluated this hypothesis. Attentional-blink methodology was combined with voluntary spatial cuing in a visual search task: Intertarget lag was used to manipulate identity extraction; predictive cues were used to signal target locations. Central digit cues in Experiment 1 required participants to identify digits before voluntarily directing attention to a corresponding location, whereas flashed dots in Experiment 2 (indicating an opposite location) required attentional redeployment without prior cue identification. Consistent with the dual-pathway hypothesis, cuing was impaired only when the first target and the number cue competed for ventral-pathway mechanisms. Collectively, the results support the dual-pathway account of the separability of spatial selection and identity extraction.
Ghorashi
Shahab
S
Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC V6T1Z4, Canada. ghorashi@psych.ubc.ca
Spalek
Thomas M
TM
Enns
James T
JT
Di Lollo
Vincent
V
D054518:Attentional Blink / Q000502:physiology; D003118:Color Perception; D003463:Cues; D004192:Discrimination, Psychological / Q000502:physiology; D006801:Humans; D009474:Neurons / Q000502:physiology; D009949:Orientation / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology; D011601:Psychophysics; D011930:Reaction Time / Q000502:physiology; D014795:Visual Pathways / Q000502:physiology