Objective: To investigate the visual attention mechanisms of brain, the "cue-target" experimental paradigm was adopted, and the attended range was cued by different Chinese characters.
Method: Sixteen healthy young participants (8 male and 8 female, 19-24 years old with an average of 21) served as the subjects. The stimulus sequence was "background-cue-target". The background was comprised of three homocentric white circles. Cue was the Chinese character " large", "median" and " small ". There were 8 capital English letters in each circle, which formed three homocentric circles. "T" was designed as the target stimulus. When the cue was large, the target "T" appeared within the three circles. When the cue was medium, "T" appeared within the medium and small circles. When the cue was small, the T maybe appeared only within the small circle.
Result: The reaction time became short with the decrease of the cue scale, while P1 and N1 components amplitudes increased.
Conclusion: These results not only provided the electrophysiological evidence for the spot light theory, but also indicated that the spot-light effect happened at the early period of the information processing.