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Suggested by various findings of the models of lexical access that word recognition and retrieval are influenced by several key characteristics of words, in the next section, the influences of word access and organization will be investigated based on the viewpoints of the structure of the mental lexicon models we discussed before.
2.2 Influences of Word Access and Organization
Word access and organization are sorted and influenced by the following factors:
(a) frequency effect, (b) imageability, (c) lexical bias, (d) lexical categories, and (e) phonological similarity4. For instance, evidence of frequency effect was found by Dell (1990), Kittredge, Dell, Verkuilen and Schwartz (2008), and Nozari, Kittredge, Dell and Schwartz (2010); evidence of imageability was found by De Groot (1989), De Deyne and Storms (2008), and Malhi (2018); evidence of lexical bias was found by Dell (1985), Dell and O’Seaghdha (1991, 1992), and Oppenheim and Dell (2008); evidence of lexical categories was found by Dell (1990), Nissen and Henriksen (2006), and De Simone and Collina (2016); evidence of phonological similarity was found by Dell (1985, 1986, 1988), Dell, Reed, Adams and Meyer (2000), Vitevitch (2008), Vitevitch and Goldstein (2014), Beckage and Colunga (2016), and Rebei, Anderson and Dell (2019).
To understand and figure out the possible variabilities which may affect the result of the word association tasks in the present study, the influences of lexical access is mainly
4 Several studies also concerned the effect from the age of acquisition in lexical retrieval;
however, this influence does not fit the research purpose in the present study, so it will not be discussed thoroughly.
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according to Reeves et al.’s (1998) organization regarding the evidence from other researchers mentioned above, and will be carefully discussed in the following sections5.
2.2.1 Frequency
Frequency effect is caused by words being experienced in diverse contexts rather just an individual’s language experience. Evidence from a large number of research have been consistently shown that lexical frequency has an effect on lexical processing. Dell (1990) applied a spreading-activation model of lexical retrieval in both production and recognition, and found that it was frequency but not the vocabulary types (function and content morphemes) that put influences on phonological errors. Kittredge et al. (2008) found evidence from aphasic picture-naming error that lexical frequency had significant influences on both phonologically and semantically related errors. Nozari, Kittredge, Dell and Schwartz (2010) found that results were sensitive to frequency effect in both aphasic picture naming and auditory word repetition tasks with both of the semantic and phonological steps involved.
Further pieces of the evidence about the frequency effects were located such as at the retrieval of a word’s phonological and semantic characteristics. Therefore, frequency effect influences the way a word being chosen to produce for a presentation of the meaning that a speaker wants to convey. The principle of frequency in lexical access also interacts with concreteness which will be introduced in the following.
5 Reeves, Hirsh-Pasek and Golinkoff (1998) proposed five factors influencing word access and organization including frequency, imageability and concreteness and abstractness, semantics,
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2.2.2 Imageability
Imageability deals with the issue between concreteness and abstractness of a concept, in which the former concept is easier to be come up with internal pictures such as
‘tree’; on the contrary, the latter one is more difficult to generate an image of the word meaning, for instance, ‘freedom’. As mentioned in the last section, imageability also interacts with frequency; therefore, words with high frequency and high concreteness (e.g.,
‘apple’) are best accessed and recalled, and vice versa. That is, in comparison, abstract words with low frequency are later and/or more difficult to be retrieved from the mental lexicon. De Groot (1989) found that word imageability strongly determines responses in word association, and this effect also interacts with the frequency variable in lexical decision task. However, De Deyne and Storms’ (2008) experimental results somehow contradicted De Groot’s finding that most core nodes in the mental lexicon have high frequency due to being early acquired, i.e., the nodes are therefore retrieved more times, but not necessarily associated with mental imagery. On the other hand, Caplan and Madan (2016) also proposed that imageability is one of the most important factors that involves in the process of the lexical access and organization. In their research, words with higher imageability were better recalled than those with lower imageability during the associative processing; furthermore, that was the imageability instead of the lexical effect, a preference on a real word or not, that enhanced the strength between association and memory.
Therefore, concrete words with rich semantic representations are attested to be accessed easier and be stored deeper in the brain, i.e., in the core of the mental lexicon.
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2.2.3 Lexical Bias
Most evidence of lexical bias effect come from speech errors, and this effect refers to the tendency for phonological speech errors to result in real words rather than nonwords.
One of the general effects on phoneme-morpheme feedback in the model proposed by Dell (1985) is lexical bias, i.e., a speaker would have the tendency to create morphemes for an existent word. The causes of lexical bias were described with his explanations of the semantic influences on different levels of the language perception including the effects of the lexical context on the perception of letters. Also, the semantic stimuli on the perception of words, and that on the production of a string of phonemes lead to the lexical bias effect as well. This effect has been supported by the latter studies about lexical priming and the stages of lexical access (e.g., Dell & O’Seaghdha, 1991, 1992). Oppenheim and Dell (2008) further examined both lexical bias and phonemic similarity effect between inner and overt speech, in which the inner speech indicates the voices produced in mind, and the latter one means the speech spoken out loud. The results contributed that lexical bias presented in both inner and overt speech errors, which demonstrate the great effect of the lexical bias for the lexical access and organization.
2.2.4 Syntactic Category
Different syntactic categories serve different functions in language. Words from different syntactic categories operate differently in terms of the manner and degree of integration into the word web, along with the way to establish vertical and horizontal semantic and syntactic relations to other words. Therefore, it is important to distinguish
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their respective networks and understand its influences on the lexical access and organization.
In Dell’s experiment (1990) about the effects of frequency and vocabulary type on phonological speech errors, the evidence showed a distinctive frequency effect between two types of vocabulary, i.e., function and content words, when they were presented as a whole syntactic unit, even if the function and content morphemes were not distinguished in the lexical access and recognition. Nissen and Henriksen (2006) found a clear evidence of lexical category affecting the responses in word association test, especially that nouns elicit a higher proportion of paradigmatic responses than verbs and adjectives. Words are classified as paradigmatic relation by being distinguished between alternative semantic connections, but locating within the same syntactic slot; words are classified assyntagmatic relation by connecting syntactic relations and combining the semantic connections.
De Simone and Collina (2016) proposed an evidence of the syntactic category effects from the activation of lexical categories. This type of activation conveys between the representation of the lexical categories during lexical access and production, and before the target word is selected, all the candidate word with strong connections, i.e., the words sharing the same grammatical category, spreads the activation to each other.Furthermore, the syntactic category effects were considered as independent from semantic in their experiments because they still emerged though one of the influences was controlled.
2.2.5 Phonological Similarity
Phonology constructs the integral basis of language network representations. A large amount of studies have investigated phonological networks mostly by the analysis of
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speech production errors (e.g., Dell, 1985, 1986, 1988; Dell, Reed, Adams & Meyer, 2000;
Vitevitch, 2008; Vitevitch & Goldstein, 2014; Beckage & Colunga, 2016; Rebei, Anderson
& Dell, 2019). Dell, Reed, Adams and Meyer (2000) proposed that the presence of nonwords from phonological speech errors happens often, but the chance of the violation of phonotactic constraints shows relatively small because the preferences that certain phonemes appear in the position of the word-initial or word-final are ruled by the language.
Take English consonant [ŋ] for example, if [n] is mispronounced as [ŋ], the [ŋ] will always appear in the word-final. Phonological similarity was illustrated as well when Vitevitch (2008) presented a small portion of the English phonological network by 20,000 English word-forms for word speech and the neighbors of speech, in whichnodes represent words in the lexicon; links connect words with phonological similarity as Figure 2-2-1 below.
Figure 2-2-1. A sample of words from the English phonological network analyzed in Vitevitch (2008)
The figure illustrates the word speech, the neighbors of speech, and the neighbors of those neighbors. For example, the node for the word ‘peach’ /pitʃ/ would have a link connecting
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it to the nodes representing the words ‘preach’ /pɹitʃ/, ‘peat’ /pit/, ‘patch’ /pæ tʃ/, ‘each’ /itʃ/, etc. These examples explain the phonological similarity of the words with /p/ as the onset, their minimal pairs (e.g., ‘preach’ /pɹitʃ/ and ‘each’ /itʃ/), or words with similar phonological conditions (e.g., ‘speak’ /spik/ and ‘speed’ /spid/). The first two ones connect to each other directly; however, the latter ones have at least one node between them in the phonological network of the mental lexicon.
Beckage and Colunga (2016) mentioned the same phonological similarity as Vitevitch based on ‘edit distance’, i.e., transformations (e.g., substitution, insertion, and deletion) of one word into another word by a series of phoneme changes. For example, the word ‘kit’ can transfer to ‘hit’ with the substitution of the onset from /k/ to /h/; to the word
‘skit’ via inserting another consonant /s/ in the word-initial to constitute the consonant cluster /sk/; to the word ‘it’ by deleting the onset /k/ and remaining the rhyme.