Читать книгу The Science of Reading - Группа авторов - Страница 62

The presence of anagrams in alphabetic languages forces attention to be paid to letter‐in‐word order. The issue here is just how much “attention” to letter‐order information is needed. At one extreme is the length‐dependent, position‐specific slot‐coding used in the interactive‐activation model (McClelland & Rumelhart, 1981) according to which the reader knows precisely which letter is at which position in a word of a given length. Although probably only applied for computational convenience, this coding scheme had the advantage of generating precise predictions with respect to effects of orthographic similarity on visual word recognition (see previous section). Nevertheless, a number of empirical findings challenge this view and point to the need for a more flexible letter‐position coding scheme. Much of this evidence comes from experiments using the masked priming paradigm (Forster & Davis, 1984; see Adelman et al., 2014, for a mega‐study) whereby target words are preceded by various types of word or nonwords primes. Taken together, findings from these experiments indicate a certain flexibility in the way an orthographic description of the stimulus (letter identities and letter positions) is matched with whole‐word orthographic representations in long‐term memory.

One key piece of evidence that forced a re‐consideration of how letter position information is encoded during orthographic processing was provided by experiments demonstrating effects of orthographic overlap between two stimuli of different length. One important finding, first reported by Humphreys et al. (1990), is that facilitatory masked priming can be obtained from orthographically related nonword primes that are not the same length as the target word (e.g., bvk as a prime for the target word black). Referred to as the relative‐position priming constraint by Grainger et al. (2006), this finding is important because it falsifies the simple length‐dependent, slot‐based letter position coding implemented in the original interactive‐activation model. The basic effect is well replicated (Peressotti & Grainger; 1999; Schoonbaert & Grainger, 2004) and extends to superset primes where primes (e.g., garbdfen) facilitate target word processing (e.g., garden) albeit with a cost of approximately 10 ms per inserted letter (e.g., Adelman et al., 2014; van Assche & Grainger, 2006). These priming effects are related to another phenomenon that illustrates the flexibility of letter position encoding. Participants in Bowers et al. (2005) found it hard to reject the word that as an item of clothing, arguably because the embedded word hat provided evidence that the stimulus did refer to an item of clothing. Once again, this finding is incompatible with length‐dependent slot‐coding of letter position information, and points to a greater degree of flexibility in the manner in which letter‐position information or letter‐order information is encoded during visual word recognition.

Perhaps the single key finding that drew attention to the fact that letter identities are not tied to a strictly length‐dependent position‐in‐word is the effect of small changes in the order of the letters in a word – so‐called transposed‐letter effects. Following earlier reports (e.g., Bruner & O’Dowd, 1958; Chambers, 1979), key findings using the masked priming paradigm (Perea & Lupker, 2003, 2004) are among the most replicated effects in experimental psychology. The standard finding is that primes formed by transposing two letters of a target word facilitate processing of the target words compared with primes formed by substituting the same letters (e.g., caniso – CASINO vs. carivo – CASINO, Perea & Lupker, 2004). It is now established that priming is greater when at least one of the transposed letters is a consonant (Lupker et al., 2008; Perea & Lupker, 2004); that priming diminishes as the distance between the two transposed letters increases (e.g., Perea et al., 2008); and that priming diminishes when the transposition involves an outer letter (e.g., Perea & Lupker, 2003).