Edge-aligned embedded word activation initiates morpho-orthographic segmentation

Current evidence suggests that morphologically complex words (e.g., farmer) are automatically segmented into their constituent morphemes (farm +. er) during reading, a process referred to as "morpho-orthographic segmentation." Intriguingly, the evidence also suggests that this segmentation process even operates on words with a pseudo-morphological structure (e.g., corner: corn +. er). Here we describe an account of morpho-orthographic segmentation for derivational morphology in non-agglutinative Latinate languages that underlines the key role played by edge-aligned embedded word activation. According to this account, affixes play a secondary role in the segmentation process, helping segmentation during the early processing of complex words only when embedded word activation is hindered. This provides a mechanism for initiating morpho-orthographic segmentation without appealing to specialized morphological representations. Use of edge-aligned embedded word activation is also thought to be the starting point of morpho-orthographic processing during reading development, such that efficient processing of embedded stems developmentally precedes processing of affixes as orthographic entities. Furthermore, it is the hypothesized delayed learning of orthographic representations for bound morphemes (morphemes that are not free-standing words), such as affixes, that accounts for the developmental trajectory of morpho-orthographic priming effects and the overall influence of morphological structure on processing morphologically complex stimuli. Our account of morpho-orthographic segmentation explains both the standard pattern of masked priming effects found with truly complex (e.g., farmer) and pseudo-complex (e.g., corner) words, as well as the pattern of priming effects obtained with complex nonword primes (e.g., farmage, cornity).