Stefanie Regel

Isn't it ironic? an electrophysiological exploration of figurative language processing

Although the neurocognitive processes underlying the comprehension of figurative language, especially metaphors and idioms, have been studied extensively, less is known about the processing of irony. In two experiments using event-related brain potentials (ERPs), we examined the types of cognitive processes involved in the comprehension of ironic and literal sentences and their relative time course. The experiments varied in modality (auditory, visual), task demands (comprehension task vs. passive reading), and probability of stimulus occurrence. ERPs consistently revealed a large late positivity (i.e., P600 component) in the absence of an N400 component for irony compared to equivalent literal sentences independent of modality. This P600 was shown to be unaffected by the factors task demands and probability of occurrence. Taken together, the findings suggest that the observed P600 is related to irony processing, and might be a reflection of pragmatic interpretation processes. During the comprehension of irony, no semantic integration difficulty arises (absence of N400), but late inferential processes appear to be necessary for understanding ironic meanings (presence of P600). This finding calls for a revision of current models of figurative language processing.

Distinguishing Neurocognitive Processes Reflected by P600 Effects: Evidence from ERPs and Neural Oscillations

Research on language comprehension using event-related potentials (ERPs) reported distinct ERP components reliably related to the processing of semantic (N400) and syntactic information (P600). Recent ERP studies have challenged this well-defined distinction by showing P600 effects for semantic and pragmatic anomalies. So far, it is still unresolved whether the P600 reflects specific or rather common processes. The present study addresses this question by investigating ERPs in response to a syntactic and pragmatic (irony) manipulation, as well as a combined syntactic and pragmatic manipulation. For the syntactic condition, a morphosyntactic violation was applied, whereas for the pragmatic condition, such as “That is rich”, either an ironic or literal interpretation was achieved, depending on the prior context. The ERPs at the critical word showed a LAN-P600 pattern for syntactically incorrect sentences relative to correct ones. For ironic compared to literal sentences, ERPs showed a P200 effect followed by a P600 component. In comparison of the syntax-related P600 to the irony-related P600, distributional differences were found. Moreover, for the P600 time window (i.e., 500–900 ms), different changes in theta power between the syntax and pragmatics effects were found, suggesting that different patterns of neural activity contributed to each respective effect. Thus, both late positivities seem to be differently sensitive to these two types of linguistic information, and might reflect distinct neurocognitive processes, such as reanalysis of the sentence structure versus pragmatic reanalysis.

The past tense debate revisited: Electrophysiological evidence for subregularities of irregular verb inflection

Neuropsychological research investigating mental grammar and lexicon has largely been based on the processing of regular and irregular inflection. Past tense inflection of regular verbs is assumed to be generated by a syntactic rule (e.g., show-ed), whereas irregular verbs consist of rather unsystematic alternations (e.g., caught) represented as lexical entries. Recent morphological accounts, however, hold that irregular inflection is not entirely rule-free but relies on morphological principles. These subregularities are computed by the syntactic system. We tested this latter hypothesis by examining alternations of irregular German verbs as well as pseudowords using ERPs. Participants read series of irregular verb inflection including present tense, past participle, and past tense forms embedded in minimal syntactic contexts. The critical past tense form was correct (e.g., er sang [he sang]) or incorrect by being either partially consistent (e.g., *er sung [*he sung]) or inconsistent (e.g., *er sing [*he sing]) with the proposed morphological principles. Correspondingly, in a second experimental block, pseudowords (e.g., tang/*tung/*ting) were presented. ERPs for real words revealed a biphasic ERP pattern consisting of a negativity and P600 for both incorrect forms in comparison to the correct equivalents. Most interestingly, the P600 amplitude for the incorrect forms was gradually modulated by the type of anomaly with medium amplitude for consistent past tense forms and largest amplitude for inconsistent past tense forms. ERPs for pseudoword past tense forms showed a similar gradual modulation of N400. The findings support the assumption that irregular verbs are processed by rule-based mechanisms because of subregularities of their past tense inflection.

Processing inflectional morphology: ERP evidence for decomposition of complex words according to the affix structure

This study investigated the processing of inflectional morphology by registrating event-related brain potentials (ERPs) during sentence reading. In particular, we examined nouns combined with affixes that have distinct structural characteristics as proposed by morphological theory. Affixes were either complex consisting of functionally distinguishable subparts as occurring for German plural morphology, or simple consisting of one part only. To test possible differences in processing these affixes we compared grammatical nouns [e.g., Kartons (cartons)] to ungrammatical ones (e.g., *Kartonen) in two different syntactic contexts represented by a complex, or simple affix. The ERPs showed that ungrammatical nouns consisting of complex affixes elicited a left anterior negativity (LAN) reflecting enhanced morphosyntactic processing, which was absent for equivalent nouns consisting of simple affixes. This finding suggests that inflected words are decomposed dependent on the affix structure, whereby the affixes themselves seem to consist of morphological subparts in accordance with current morphological theories (Müller, 2007; Noyer, 1992). Moreover, ungrammatical nouns elicited early (reduced P200) and late (P600) ERP components relative to their grammatical equivalents, which implies an engagement of syntactic processes presumably based on intially enhanced pre-lexical processing of these irregularized nouns. The findings are discussed with respect to theoretical and neuropsychological accounts to inflectional morphology.