Detecting anticipatory events in handwriting movements

We investigated how visual processes exploit specific anticipatory movement s observed in handwriting gestures. Previous research has shown that the ki nematic information contained in the downstroke of an I is exploited to pre dict the identity of the forthcoming letter. Here, we determined the moment at which prediction takes place. Two between-letter effects were examined: changes in size (II vs le) and changes in rotation direction (le vs In). R esults show that with only 75% of the I downstroke trajectory (or 60% of th e downstroke time) subjects are already capable of predicting the identity of the letter following the I, that is well before the end of the downstrok e. Analysis also reveals that identification takes place after the presenta tion of the movement acceleration phase. The visual perception of motor ant icipation seems to involve the detection of motor events.