Читать книгу The Science of Reading - Группа авторов - Страница 63

In a previous section, I described a mechanism for encoding the location of different letter identities along a line of text. This first level of orthographic processing involves the location‐specific encoding of letter identities via a horizontally aligned (for written languages with horizontally aligned scripts) bank of letter detectors. These are the gaze‐centered letters in Figure 3.4.² The second level of orthographic processing in this model is a location‐invariant sublexical orthographic code that provides information about the order of letters in a word independently of where readers’ eyes are looking at the word and prior to activating whole‐word orthographic representations. These are the word‐centered sublexical orthographic representations in Figure 3.4, which illustrates one specific scheme for encoding location‐invariant letter‐in‐word order. This particular scheme encodes letter order via a bag (i.e., an unordered set) of ordered contiguous and noncontiguous letter pairs (Whitney, 2001), referred to as open‐bigrams in Grainger and van Heuven’s (2004) model. It should be noted that this level of sublexical orthographic processing, the encoding of letter‐in‐word order, is the starting point of all other models of orthographic processing. A number of alternative accounts have been proposed for how this is achieved, such as the noisy spatial coding scheme (Davis, 2010) and the noisy length‐dependent ordinal encoding applied in the overlap model (Gomez et al., 2008). Positional noise is added to these coding schemes in order to account for transposed‐letter effects (see previous section). In Grainger and van Heuven’s model on the other hand, positional noise operates on the location‐specific letter detectors of the first level of processing.³ That is, transposed‐letter effects are a direct result of the location‐invariant order encoding scheme, and not just the result of positional noise.