Conférence de Ralf Engbert (University of Potsdam,
Germany), le vendredi 13 novembre 2009 à 11
h, Salle des Voûtes, Pôle 3C, Centre St Charles,
Université de Provence, Marseille : «Bayesian
estimation for saccade planning during reading».
Résumé
During reading, saccadic eye movements are needed to move words
into the center of the visual field for lexical processing.
Saccadic landing positions within words show a pronounced peak
close to the word center with an additional systematic error, which
is modulated by the distance of the launch site and the length of
the target word (the launch site effect).
In my talk, I demonstrate that the systematic variation of fixation
positions within words might be a consequence of Bayesian
estimation. I present a mathematical model for the launch site
effect, which makes explicit assumptions on underlying visual and
oculomotor processes. Based on eye-movement recording, I show
experimental results that are consistent with the view that readers
use Bayesian estimation for saccade planning.
Finally, I discuss the importance of mislocated fixations for the
unbiased estimation of distributions of within-word landing
positions.