Effects of morphological complexity on phonological output deficits in fluent and nonfluent aphasia

This study examined the effects of morphological complexity on aphasic speakers with lexical-phonological output deficits. Subjects were two fluent and two nonfluent aphasic speakers who repeated morphologically simple words at the same level of accuracy and whose errors were virtually all phonological in nature. They were asked to repeat a variety of morphologically complex (i.e., affixed) words. Results were interpreted within our two-stage model of lexical-phonological production (Kohn & Smith, 1994, 1995), which we expand to include a distinction between derivational and inflectional morphology. When comparing overall performance levels between morphologically simple and complex words, only three subjects exhibited more difficulty repeating the morphologically complex targets. Nevertheless, when comparing repetition accuracy between different types of morphologically complex words (e.g., derived vs. inflected), all four subjects displayed similar patterns. These findings suggested that while morphological complexity has different effects on the two stages within the lexical-phonological output system, the relative effects of different morphological structures are constant. At the level of error analysis, patterns of affix errors distinguished the nonfluent from the fluent subjects in ways that are reminiscent of the affix errors associated with agrammatic and paragrammatic speech. This finding raised questions concerning the relationship between morphosyntactic and morphophonological deficits.     

Inflectional and derivational morphology in the mental lexicon: Symmetries and asymmetries in repetition priming

Using a repetition priming paradigm, the interrelations between morphologically related words in the mental lexicon were examined in two experiments. In contrast to most previous studies, in which morphologically complex words occur as primes and stems as targets, derivationally and inflectionally complex forms were fully crossed in prime-target pairs. Experiment 1 showed asymmetries in the pattern of priming effects between different inflectional forms of German adjectives. Such asymmetries are problematic for any theory that assumes that all members of an inflectional paradigm share one entry in the mental lexicon. Experiment 2 contrasted derivational and inflectional variants of the same stems used in Experiment 1. Once again, there were same clear asymmetries in the pattern of priming effects. The implications of these results for models of lexical organization of inflectional and derivational morphology are discussed.     

Analogical effects in reading Dutch verb forms

Previous research has shown that the production of morphologically complex words in isolation is affected by the properties of morphologically, phonologically, or semantically similar words stored in the mental lexicon. We report five experiments with Dutch speakers that show that reading an inflectional word form in its linguistic context is also affected by analogical sets of formally similar words. Using the self-paced reading technique, we show in Experiments 1-3 that an incorrectly spelled suffix delays readers less if the incorrect spelling is in line with the spelling of verbal suffixes in other inflectional forms of the same verb. In Experiments 4 and 5, our use of the self-paced reading technique shows that formally similar words with different stems affect the reading of incorrect suffixal allomorphs on a given stem. These intra- and interparadigmatic effects in reading may be due to online processes or to the storage of incorrect forms resulting from analogical effects in production.     

Morphology by itself in planning the production of spoken words

The authors report a study in Dutch that used an on-line preparation paradigm to test the issue of semantic dependency versus morphological autonomy in the production of polymorphemic words. Semantically transparent complex words (likeinput in English) and semantically opaque complex words (likeinvoice) showed clear evidence of morphological structure in word-form encoding, since both exhibited an equally large preparation effect that was much greater than that for morphologically simple words (likeinsect). These results suggest that morphemes may be planning units in the production of complex words, without making a semantic contribution, thereby supporting the autonomy view. Language production establishes itself as a domain in which morphology may operate “by itself” (Aronoff, 1994) without recourse to meaning.     

汉语双字词在心理词典中的表征方式:来自fNIRS的证据

以汉语双字构成的真词与假词为实验材料,22名大学生为被试,采用功能性近红外脑成像技术(f NIRS)和事件相关设计,考察被试在完成词汇判断任务时的大脑激活模式,探索汉语双字词在心理词典中的表征方式。结果发现:(1)在完成真假词判断任务时,被试大脑左侧额叶和左侧颞叶均被激活;(2)与判断假词相比,被试在判断真词时显著地激活左额上回和左额中回。这一结果说明汉语双字词在心理词典中是混合表征的。     

Morphological decomposition and the reverse base frequency effect

If recognition of a polymorphemic word always takes place via its decomposition into stem and affix, then the higher the frequency of its stem (i.e., base frequency) the easier the lexical decision response should be when frequency of the word itself (i.e., surface frequency) is controlled. Past experiments have demonstrated such a base frequency effect, but not under all circumstances. Thus, a dual pathway notion has become dominant as an account of morphological processing whereby both decomposition and whole-word access is possible. Two experiments are reported here that demonstrate how an obligatory decomposition account can handle the absence of base frequency effects. In particular, it is shown that the later stage of recombining the stem and affix is harder for high base frequency words than for lower base frequency words when matched on surface frequency, and that this can counterbalance the advantage of easier access to the higher frequency stem. When the combination stage is crucial for discriminating the word items from the nonword items, a reverse base frequency effect emerges, revealing the disadvantage at this stage for high base frequency words. Such an effect is hard for the dual-pathway account to explain, but follows naturally from the idea of obligatory decomposition.     

Recognition of Inflected Words in a Morphologically Limited Language: Frequency Effects in Monolinguals and Bilinguals

The effect of word frequency on the processing of monomorphemic vs. inflected words was investigated in a morphologically relatively limited language, Swedish, with two participant groups: early Finnish–Swedish bilinguals and Swedish monolinguals. The visual lexical decision results of the monolinguals suggest morphological decomposition with low-frequency inflected nouns, while with medium- and high-frequency inflections, full-form processing was apparently employed. The bilinguals demonstrated a similar pattern. The results suggest that morpheme-based recognition is employed even in a morphologically limited language when the inflectional forms occur rarely. With more frequent inflectional forms, full-form representations have developed for both mono- and bilingual speakers. In a comparable study employing a morphologically rich language, Finnish, Lehtonen and Laine (2003, Bilingualism: Language and Cognition, 6, 213–225) observed full-form access only at the high-frequency range and only for monolinguals. These differences suggest that besides word frequency and language background, the morphological richness of a language affects the processing mode employed with polymorphemic wordsThis study was financially supported by a grant (#20010) from the Joint Committee of the Nordic Social Science Research Councils (NOS-S). We are grateful for Jonna Kortelahti- Brunnsteiner for recruitment and testing of part of the bilingual participants     

Production of Inflected Novel Words in Older Adults With and Without Dementia

While cognitive changes in aging and neurodegenerative disease have been widely studied, language changes in these populations are less well understood. Inflecting novel words in a language with complex inflectional paradigms provides a good opportunity to observe how language processes change in normal and abnormal aging. Studies of language acquisition suggest that children inflect novel words based on their phonological similarity to real words they already know. It is unclear whether speakers continue to use the same strategy when encountering novel words throughout the lifespan or whether adult speakers apply symbolic rules. We administered a simple speech elicitation task involving Finnish-conforming pseudo-words and real Finnish words to healthy older adults, individuals with mild cognitive impairment, and individuals with Alzheimer's disease (AD) to investigate inflectional choices in these groups and how linguistic variables and disease severity predict inflection patterns. Phonological resemblance of novel words to both a regular and an irregular inflectional type, as well as bigram frequency of the novel words, significantly influenced participants' inflectional choices for novel words among the healthy elderly group and people with AD. The results support theories of inflection by phonological analogy (single-route models) and contradict theories advocating for formal symbolic rules (dual-route models).     

Interaction of morphological structure and prefix transparency in the processing of Bulgarian aspectual verb forms

This study investigates the processing of polymorphemic words in a highly inflected language, Bulgarian. The roles of semantic transparency, aspect, and bound or free root status in the recognition of aspectual verb forms were probed in the visual modality in a simple lexical decision and a masked priming experiment at a short SOA. Results from the two experiments yielded effects of semantic transparency and morphological complexity, demonstrating that both factors influence the recognition of prefixed aspectual forms in Bulgarian and pointing toward different access procedures. In contrast, the status of the root did not influence recognition patterns, suggesting that free-standing and bound roots are equivalent lexical units of access and representation in Bulgarian.     

Do transposed-letter similarity effects occur at a morpheme level? Evidence for morpho-orthographic decomposition

When does morphological decomposition occur in visual word recognition? An increasing body of evidence suggests the presence of early morphological processing. The present work investigates this issue via an orthographic similarity manipulation. Three masked priming lexical decision experiments were conducted to examine the transposed-letter similarity effect (e.g., jugde facilitates JUDGE more than the control jupbe) in polymorphemic and monomorphemic words. If morphological decomposition occurs at early stages of visual word recognition, we would expect an interaction with transposed-letter effects. Experiment 1 was carried out in Basque, which is an agglutinative language. The nonword primes were created by transposing two letters that either crossed the morphological boundaries of suffixes or did not. Results showed a transposed-letter effect for non-affixed words, whereas there were no signs of a transposed-letter effect across morpheme boundaries for affixed words. In Experiment 2, this issue was revisited in a non-agglutinative language (Spanish), with prefixed and suffixed word pairs. Again, results showed a significant transposed-letter effect for non-affixed words, whereas there were no signs of a transposed-letter effect across morpheme boundaries for affixed words (both prefixed words and suffixed words). Experiment 3 replicated the previous findings, and also revealed that, for polymorphemic words, transposed-letter priming effects occurred for within-morpheme transpositions. Taken together, these findings support the view that morphological decomposition operates at an early stage of visual word recognition.     

Reading development in agglutinative languages: Evidence from beginning,intermediate, and adult Basque readers

Do typological properties of language, such as agglutination (i.e., the morphological process of adding affixes to the lexeme of a word), have an impact on the development of visual word recognition? To answer this question, we carried out an experiment in which beginning, intermediate, and adult Basque readers (n = 32 each, average age = 7, 11, and 22 years, respectively) needed to read correctly versus incorrectly inflected words embedded in sentences. Half of the targets contained high-frequency stems, and the other half contained low-frequency stems. To each stem, four inflections of different lengths were attached (-a, -ari, -aren, and -arentzat, i.e., inflectional sequences). To test whether the process of word recognition was modulated by the knowledge of word structure in the language, half of the participants’ native language was Basque and the other half’s native language was Spanish. Children showed robust effects of frequency and length of inflection that diminished with age. In addition, the effect of length of inflection was modulated by the frequency of the stem and by the native language. Taken together, these results suggest that word recognition develops from a decoding strategy to a direct lexical access strategy and that this process is modulated by children’s knowledge of the inflectional structure of words from the beginning of their reading experience.     

Interference in implicit memory caused by processing of interpolated material

This study addresses the susceptibility of implicit memory to interference. Interference is manipulated by presenting interpolated lists of words that do or do not have word stems in common with previously studied target words (e.g., target word paragraph followed by interpolated words such as paradise or vicinity). Interference in a word stem completion task occurred only when words had similar word stems (Experiment 1). Increasing the number of interpolated words with corresponding word stems (e.g., not only paradise but also parking, pardon, and parliament) produced increasing amounts of interference (Experiment 2). Interference in implicit memory appears to be a simple response competition phenomenon that occurs when cues simultaneously activate primed targets and primed competing responses. The amount of interference can be explained by a quantitative model of the relative strengths of target and competing responses.     

Prosodic cues for morphological complexity: The case of Dutch plural nouns

It has recently been shown that listeners use systematic differences in vowel length and intonation to resolve ambiguities between onset-matched simple words (Davis, Marslen-Wilson, & Gaskell, 2002; Salverda, Dahan, & McQueen, 2003). The present study shows that listeners also use prosodic information in the speech signal to optimize morphological processing. The precise acoustic realization of the stem provides crucial information to the listener about the morphological context in which the stem appears and attenuates the competition between stored inflectional variants. We argue that listeners are able to make use of prosodic information, even though the speech signal is highly variable within and between speakers, by virtue of the relative invariance of the duration of the onset. This provides listeners with a baseline against which the durational cues in a vowel and a coda can be evaluated. Furthermore, our experiments provide evidence for item-specific prosodic effects.     

Stem allomorphy in the Spanish mental lexicon: evidence from behavioral and ERP experiments

This study presents results from a nonce-word elicited production task and a reading experiment using event-related brain potentials (ERPs) investigating finite forms of Spanish verbs which consist of marked stems and regular person and number agreement suffixes. The first experiment showed that unmarked stems are productively extended to nonce words, whereas marked stems generalize more restrictively to nonce words, based on lexical similarity to existing stem forms. The second experiment yielded a lexical ERP signature for stem violations and an ERP pattern signaling morpho-syntactic (rule-based) processing for suffix violations. We argue that stem allomorphy is lexically represented in the Spanish mental lexicon, with marked stems forming subnodes of structured lexical entries.     

In search of meaning: semantic effects on past-tense inflection

Within single-mechanism connectionist models of inflectional morphology, generating the past-tense form of a verb depends upon the interaction of semantic and phonological representations, with semantic information being particularly important for irregular or exception verbs. We assessed this hypothesis in two experiments requiring normal speakers to produce the past tense from a verb stem that takes a regular or exceptional past tense. Experiment 1 revealed significant latency advantages for high- over low-imageability words for both regular verbs (e.g., "lunged" faster than "loved") and exception items (e.g., "drank" faster than "dealt"); but critically, this effect was significantly larger for exceptions than for regulars. Experiment 2 employed a semantic priming paradigm where participants inflected verb stems (e.g., sit) preceded by related (e.g., chair) or unrelated primes (e.g., jug) and revealed a priming effect in accuracy that was confined to the exception items. Our results are consistent with predictions from single-mechanism connectionist models of inflectional morphology and converge with findings from neurological patients and studies of reading aloud.     

How to drastically reduce priming in word stem completion—and still present the words

This paper describes a series of experiments in which we demonstrated that "dysphonemic" word stems, which are likely not pronounced in isolation as they are within a word (e.g., MUS in MUSHROOM or LEG in LEGEND), showed less priming than did "phonemic stems" (e.g., MUS in MUSTARD or LEG in LEGACY). Furthermore, words with either dysphonemic or phonemic three-letter stems gave rise to equivalent levels of priming when test cues were four-letter stems (LEGE) or word fragments (L_G_ND). Moreover, the difference between phonemic and dysphonemic stems persisted when nonpresented completion rates were matched. A final cued-recall experiment revealed that performance was greater for phonemic stems than for dysphonemic stems and that this difference was greater for older participants than for younger ones. These results are not readily accounted for by extant theoretical approaches and point to important methodological issues regarding stem completion.     

汉语并列式合成词的词汇通达

汉语并列式合成词具有三种类型,这三种类型内部不同的词素组合在心理词典中则需要不同的词汇通达时间。实验结果表明,在对汉语并列式合成词的词汇通达过程中,第一成分并不总是起决定作用;同样,并列式合成词中的两个成分在词汇通达过程中并不总是同等重要。实验证明,语义透明度对并列式合成词的词汇通达起重要作用。实验还发现,在心理词典中对并列式合成词的词汇通达需要一个证实原则。     

An amorphous model for morphological processing in visual comprehension based on naive discriminative learning

A 2-layer symbolic network model based on the equilibrium equations of the Rescorla-Wagner model (Danks, 2003) is proposed. The study first presents 2 experiments in Serbian, which reveal for sentential reading the inflectional paradigmatic effects previously observed by Milin, Filipovi? ?ur?evi?, and Moscoso del Prado Martín (2009) for unprimed lexical decision. The empirical results are successfully modeled without having to assume separate representations for inflections or data structures such as inflectional paradigms. In the next step, the same naive discriminative learning approach is pitted against a wide range of effects documented in the morphological processing literature. Frequency effects for complex words as well as for phrases (Arnon & Snider, 2010) emerge in the model without the presence of whole-word or whole-phrase representations. Family size effects (Moscoso del Prado Martín, Bertram, H?iki?, Schreuder, & Baayen, 2004; Schreuder & Baayen, 1997) emerge in the simulations across simple words, derived words, and compounds, without derived words or compounds being represented as such. It is shown that for pseudo-derived words no special morpho-orthographic segmentation mechanism, as posited by Rastle, Davis, and New (2004), is required. The model also replicates the finding of Plag and Baayen (2009) that, on average, words with more productive affixes elicit longer response latencies; at the same time, it predicts that productive affixes afford faster response latencies for new words. English phrasal paradigmatic effects modulating isolated word reading are reported and modeled, showing that the paradigmatic effects characterizing Serbian case inflection have crosslinguistic scope.     

Recognition of affixed words and the word frequency effect

Three experiments are reported in which the word frequency effect is used as a diagnostic for determining whether affixed words coming from the same stem are stored together or separately in the lexicon. Prefixed words are examined in the first experiment, inflected words in the second and third. In the first two experiments, two types of word are compared where the words in each condition are matched on surface or presented frequency but are varied on the frequency of their stems or base frequency. It is found that lexical decision times are influenced by base frequency, thus indicating that words related by affixation are stored together in the lexicon. The third experiment, however, demonstrates that when base frequency is held constant and surface frequency is varied, lexical decision times are influenced by surface frequency. The results are accounted for by a model of word recognition whereby frequency has its effect at two different stages of the recognition process.     

Direct comparison of two implicit memory tests: word fragment and word stem completion.

In 3 experiments, the implicit memory tests of word fragment and word stem completion showed comparable effects over several variables: Study of words produced more priming than did study of pictures, no levels-of-processing effect occurred for words, more priming was obtained from pictures when Ss imaged the pictures' names than when they rated them for pleasantness, and forgetting rates were generally similar for the tests. A different pattern of results for the first 3 variables occurred under explicit test conditions with the same word fragments or word stems as cues. We conclude that the 2 implicit tests are measuring a similar form of perceptual memory. Furthermore, we argue that both tests are truly implicit because they meet Schacter, Bowers, & Booker's (1989) retrieval intentionality criterion: Levels of processing of words have a powerful effect on explicit versions of the tests but no effect on implicit versions.