Form and Meaning in Morphological Processing

Whether morphologically complex words are analyzed, i.e. decomposed into their constituent morpheme, in the course of processing or not has been discussed for a couple of decades. As was explained above, competing models have been presented that do or do not include a morphological decomposition component. Among the proponents of the rule-based accounts, the degrees of the magnitude of the effect of morphological, orthographic and semantic relatedness between the stems and complex words were at issue, as well.

As will be discussed in further detail in Chapter 2, there are empirical findings showing that when a morphologically complex word is encountered prior to its base form, this facilitates the reading of the second word; so, for example, when we read see after sees, this enables us to process the simple word see faster compared to an unrelated word (the baseline). It is possible to assume that this facilitation, referred to as priming (to be discussed later in this chapter), is thanks to the morphological relatedness between these two lexical items. That is to say, we analyze sees as see and –s by applying the morphological rule, so processing the same word (see) twice leads to faster recognition by re-activating the same stem. However, there are also alternative explanations. One of them is that we store and select words in the same location of our mental lexicon in accordance with the number of letters shared;

correspondingly, it is maintained that the formal overlap between a complex word and its monomorphemic stem is the major cause of the facilitation when these two types

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of lexical items are processed, indirectly demonstrating formal decomposition in visual word recognition. The influence of the surface-form -the way that individuals process and encode the specific sequences of letters in written language- (McClung et al., 2012 p. 173) is taken as a critical construct in L1 lexical processing (e.g. Sibley et al., 2008), further languages (e.g. Heyer & Clahsen, 2015) and across languages considering the alphabetical characteristics of the first and second languages of individuals (e.g. Frost, 2005).

Another point emphasized in the literature is the role that lexical semantics plays in the process of reading. In a way similar to the letters shared by the complex words and their stems, sees and see, as an example, bear almost the same meaning.

This way of thought renders the facilitation of the processing of a complex word possible after its recognition in a stem form due to the similarity in meaning.

Imageability (Paivio, 1971), the number of semantic features (Pexman, 2012), associations between words (Balota et al., 2004), and lexical ambiguities (Beretta, Fiorentino and Poeppel, 2005) were accentuated to be among the foremost sources of meaning-based influence on lexical processing. Besides experiments on adult language users, the fundamental difference between first and second language processing is explained with reference to the relative dependence on lexical-semantic cues rather than the morpho-syntactic rules, which led to the formulation of the widely-debated Shallow-Structure Hypothesis (Clahsen & Felser, 2006), an overview of which is offered further below.

The arguments on the orthographic and semantic effect on morphological processing resulted in a more elaborate contrastive look at the facilitative elements in visual word recognition. Firstly, the need to dissect form and meaning from pure morphological effects arose. Complex words, by their natures, bear a formal and semantic connection with their stems. Therefore, detecting less effort in the processing of sees following its stem see cannot guarantee that this relative effortlessness occurred only on account of morphological factors. This quintessential overlap of form, meaning, and morphology needs to be eluded by the virtue of separating these links from each other on minimally different conditions. Thereupon, the claim that form facilitates the processing of see after sees is expected to exhaust other possibilities by making predictions on the existence of the same advantage of processing when see is encountered following seed. Along the same line, look should provide a similar convenience for the processing of see to that of sees if the effortlessness explained

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above stems purely from the meaning-based connection between the successive words.

This perspective, coupled with further analyses on the sole and collective effects of potential factors of morphological processing, obviously increased the testability and explanatory power of the hypotheses in this field of inquiry.

Apart from the competition of potential factors in visual word recognition, the question whether morphological, orthographic and semantic factors intervene in reading concurrently or asynchronously has become another main topic of discussion in the reading literature. As stated above, there are empirical findings in support of the decomposition of morphologically complex words into their constituents and the possibility of the effect of form and meaning on this process. This bottom-up stimulus-driven word segmentation is put under scrutiny from the point of intervention of these above-mentioned factors at different phases of processing. That is to say, the point at which orthographic overlap and/or semantics begin to exert influence on the recognition of morphologically complex words and the question whether there is a phase of processing which is blind to orthographic or semantic influence are further issues that occupy the center of attention in morphological processing research.

As a matter of fact, it is indisputable that these factors enter into the organization of the mental representation and the lexical access to complex words in the final state (Marslen-Wilson et al., 1994; Diependeale et al., 2011). Even though no consensus has so far been reached regarding the decisive elements of this process, studies have displayed that semantically transparent or orthographically similar lexical items cause some facilitation in visual recognition. As for early morphological processing, the attempt to identify the mechanisms that are active at this phase is at the heart of the controversy. Rastle and her collaborators (2000, 2004, 2008) came up with the form-before-meaning account, in which it is claimed that the early stages of processing morphologically complex words are solely morphology-driven. In other words, only in later stages – maybe in the final stage- do we find orthographic overlap and semantic relatedness influencing the reading performance of language users.

According to these researchers, as an example, being exposed to sees for a very short time – say 50 milliseconds - can facilitate the recognition of the stem see because the preceding word will have already been decomposed into its morphemes see and -s at the very first stage of the encounter and the stem will be reactivated when it is seen afterwards. Because of the absence of morphological relatedness, the same simulation would not be expected for seed or look, which are orthographically and semantically

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related to the stem see, respectively, if these words are not seen for a long-enough time. Although no widely-accepted counter-view against the above-mentioned account of early morphological processing was suggested for native language processing, there is an alternative hypothesis drawing the attention of researchers. The alternative hypothesis argued that when the semantic component of the morphological relatedness between two words is removed, the facilitative effect tends to decrease (Diependeale et al., 2005). The proponents of this latter argument compared the degree of facilitation of semantically transparent word pairs (e.g. farmer - FARM) with an opaque condition, in which a word contains a pseudo-morpheme and shares the same stem with the following monomorphemic lexical item (e.g., corner - CORN). The latter condition apparently does not provide a meaning-based facilitation but only a orthographic segmentation. This alternative view suggested that this early morpho-orthographic analysis can help the reader process the following word faster albeit at a significantly diminishing degree compared to a condition where the morpho-orthographic segmentation is coupled with a semantic effect. Furthermore, there are studies in nonnative processing that point to the possibility that purely orthographic overlap can produce facilitation in the processing of morphologically complex words (e.g. Heyer & Clahsen, 2015).

A good number of studies have recently yielded remarkable findings related to the very early stages of visual word recognition in different conditions; however, an agreement on what exactly determines the early processing of complex words has not been reached, especially in non-native morphological processing. Therefore, a deeper temporal look at morphological processing is essential.