Event‐Related Potentials During Controlled and Automatic Target Detection

ABSTRACT The present study investigated the role of attentional resources in the performance of controlled and automatic detection tasks. The amplitude of the P300 component of the event‐related potential has been shown to be a sensitive index of the attentional resources allocated to the perceptual processing of sensory stimuli. We found that P300s elicited in both automatic and controlled detection were large and of comparable amplitude, suggesting the involvement of a limited‐capacity mechanism in both tasks. This result is in agreement with previous behavioral studies showing equivalent dual‐task trade‐offs with both search tasks (Hoffman & Nelson, Note 1). In contrast, P300 latency was considerably reduced in the automatic task, suggesting that the main effect of practice in the detection task is to improve the discriminability of targets and distractors.