Goal: Covert attention improves discriminability and accelerates the rate of visual information processing. With exogenous cues, the benefit at the attended location and the cost at the unattended location are comparable across cue validity. Here we examined perceptual learning manipulating cue validity and using the speed-accuracy tradeoff procedure, which enables conjoint measures of discriminability and speed of information processing.

Methods: Observers performed an orientation discrimination task in which a peripheral location cue preceded a target presented alone or with distracters. The target appeared in one of 8 iso–eccentric locations. Trials were blocked by cue validity, which was known to the observers. A response tone prompted observers to respond after various lags (40–2000 ms).

Results & Conclusion: For each cue validity, discriminability shows no evidence of perceptual learning over time. Whereas processing speeds over sessions for the neutral condition, processing speed remains constant for the valid cue condtions. Across cue validity the magnitude of the attentional effect on processing speed is at maximum level from the start. These results support the automaticity of exogenous attention: The magnitude of the attentional effect, both in terms of discriminability and processing speed, is at its maximum.