The Planning of Successive Saccades in Letter Strings

Abstract

Reading is the most remarkable ordered scanning performance that people can acquire. This behavior relies on saccadic eye movements which direct the gaze to a new location in the text. Such orienting movements are produced with highly automated routines, in an environment of complex structures which offer a variety of potential targets for the eye. For the selection of one target position among many alternatives recognition processes are necessary. We will focus here on one aspect of this behavior that is concerned with the planning of successive movements within words. During reading, subjects frequently direct their gaze to two successive positions in a word, hence bringing the fovea to different parts of the words. In recent years, the conditions under which refixations take place have been investigated. It has been shown that the probability of refixation depends on the word length and the position of the initial fixation on a word (O’Regan et al. 1984 ; McConkie et al. 1988). In addition, the probability of refixation was found to be influenced by lexical factors such as word frequency (McConkie et al, 1988; Vitu, 1991) and lexical information integrated during the first fixation (Beauvillain, 1996; Pynte, 1996).