LATERALITY EFFECTS IN JUDGMENT OF IDENTITY AND POSITION OF LETTERS - SIGNAL-DETECTION ANALYSIS

In 2 experiments subjects received 100 ms tachistoscopic presentations, to left or right of fixation, of a rectangular matrix of 12 cells. On each trial 3 cells were filled, each with a different symbol drawn from a set of 12 letters and digits. In 1 (the letter experiment) subjects had to decide whether a particular letter (nominated at the end of the trial) was 1 of the 3 presented. In a 2nd (the position experiment) they had to decide whether a cell in the matrix (nominated at the end of the trial) was 1 of those that contained a symbol. Judgments were made on a 4-point rating scale, and measures of sensitivity and response bias were calculated. In the letter experiment sensitivity was greater for presentations to right of fixation, and in the position experiment for those to left.