Poster D14, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Can orienting endogenous spatial attention impact subjective awareness more than objective performance?
Marine Vernet1, Savannah Lokey1, Sara Ahmed1, Shruti Japee1, Valentinos Zachariou1, Leslie Ungerleider1; 1Laboratory of Brain and Cognition, NIMH/NIH
Visuospatial attention often improves objective visual performance by increasing the gain of the signal at the attended location and reducing noise at unattended locations. Attention is also believed to influence decision-making and thus subjective awareness: observers assign more weight to information extracted from the attended location. In this experiment, we assessed whether orienting endogenous visuospatial attention with a central visual cue differentially modulates objective performance and subjective awareness in the same discrimination task. Visual targets were laterally presented Gabor patches, either embedded in white noise (noise experiment) or presented at low contrast (contrast experiment). Participants reported the orientation of the target, either in a 3 alternative choice task allowing subjective reports (clockwise, counterclockwise or unknown) or in a 2 alternative forced-choice task for a strict objective performance evaluation (clockwise, counterclockwise). Fitting models from Signal Detection Theory showed that, for both noise and contrast experiments, attention reduced noise, but contrast gain and increased sensitivity (i.e., of objective performance) were observed only in the contrast experiment. Indeed, in the noise experiment, any signal enhancement at the target location would enhance both the target signal and the noise in which the target was embedded. Interestingly, for both experiments, more liberal decisions were taken, i.e., subjective awareness increased. The noise experiment is thus an experimental configuration where people think they see better, even if they do not. This could be explained by an internal representation of their attentional state that would influence awareness decision independent of visual signals.
Topic Area: ATTENTION: Spatial