Measurement of spatial attention in visual information processing.

点击翻译按钮获取中文摘要

This project is planned to measure attention in vision. It has four purposes : A) effect of attending to a specific feature, B) temporal characteristics of selective processing, C) measuring spatial distribution of attention in large visual field, and D) diagnostic application of attention measurement.As for purpose A,a probe recognition method was used. Red or green letters in a 8 x 8 grid matrix were briefly presented, then followed by a probe dot. Subjects were instructed to attend to the specified color letters, and to report the letter at the probe position. The distributions of attention for both attended and unattended letters were estimated on the basis of recognition scores at each matrix cell. Cone-shaped distribution was estimated, but attended distribution was larger than unattended one in both height and extent. As for purpose C,a large texture stimulus such as a small target Ts-texture embedded in a large background Ls-texture were briefly presented, then subjects detected the target and recalled its position. The target Ts in the background Ls or vice versa were detected better in the periphery than in the central area, suggesting a ring-like spatial distribution of attention. For purpose B and D,a rapid serial visual presentation task (an RSVP task) was used. A list of 15 stimuli was rapidly presented in the same position. Each stimulus in the list consisted of 9 Katakana letters arranged in 3 x 3. Subjects reported a red target letter embedded in green distractor letters. Temporal characteristics of selective processing was examined by analyzing the original positions of the reported letters. Kanji RSVP task was administered to schizophrenia for diagnostic application. Relationship between frequency of target localization and the nature of illness was examined.