The role of letter identity and letter position in orthographic priming. 
Four experiments are reported investigating orthographic priming effects in French by varying the number and the position of letters shared by prime and target stimuli.  Using both standard masked priming and the novel incremental priming technique (Jacobs, Grainger, & Ferrand, 1995), it is shown that net priming effects are affected not only by the number of letters shared by prime and target stimuli but also by the number of letters in the prime not present in the target.  Several null results are thus explained as a tradeoff between the facilitation generated by common letters and the inhibition generated by different letters.  Inhibition was significantly reduced when different letters were replaced by nonalphabetic symbols.  Facilitation effects disappeared when the common letters did not have the same relative position in the prime and target strings, thus supporting a relative-position coding scheme for letters in words.