Temporal performance fields: visual and attentional factors.

This study is the first to investigate: (a) 'temporal performance fields,' whether the speed of information accrual differs for different locations at a fixed eccentricity, and (b) whether covert attention modulates temporal dynamics differentially at isoeccentric locations. Using the speed accuracy tradeoff (SAT) procedure, we derived conjoint measures of how isoeccentric locations and precueing targets location affect speed and accuracy in a search task. The results demonstrate the existence of temporal performance fields, analogous to spatial performance fields: information accrual was fastest for target on the horizontal meridian, intermediate for targets at the intercardinal locations, slow for targets on the vertical meridian, and slowest for targets at the North (N) location (accrual time pattern: E&W<intercardinal<S<N). Surprisingly, in contrast to spatial performance fields, where covert attention enhanced discriminability at all locations to a similar degree, attention differentially sped up processing at the slower locations, with a greater benefit evident along the vertical than the horizontal meridian, particularly at the N location, and an intermediate benefit at intercardinal locations (viz., N>S>intercardinal>E&W). Hence, the compensatory effect of attention eliminated the temporal asymmetries across isoeccentric locations.