Laurent Itti, Jochen Braun, Dale Lee, Christof Koch
We previously proposed a quantitative model of early visual pro(cid:173) cessing in primates, based on non-linearly interacting visual filters and statistically efficient decision. We now use this model to inter(cid:173) pret the observed modulation of a range of human psychophysical thresholds with and without focal visual attention. Our model - calibrated by an automatic fitting procedure - simultaneously re(cid:173) produces thresholds for four classical pattern discrimination tasks, performed while attention was engaged by another concurrent task. Our model then predicts that the seemingly complex improvements of certain thresholds, which we observed when attention was fully available for the discrimination tasks, can best be explained by a strengthening of competition among early visual filters.