Comprehending conventional and novel metaphors: An ERP study

The role of literal meaning in figurative language comprehension: evidence from masked priming ERP

The role of literal meaning during the construction of meaning that goes beyond pure literal composition was investigated by combining cross-modal masked priming and ERPs. This experimental design was chosen to compare two conflicting theoretical positions on this topic. The indirect access account claims that literal aspects are processed first, and additional meaning components are computed only if no satisfactory interpretation is reached. In contrast, the direct access approach argues that figurative aspects can be accessed immediately. We presented metaphors (These lawyers are hyenas, Experiment 1a and 1b) and producer-for-product metonymies (The boy read Böll, Experiment 2a and 2b) with and without a prime word that was semantically relevant to the literal meaning of the target word (furry and talented, respectively). In the presentation without priming, metaphors revealed a biphasic N400-Late Positivity pattern, while metonymies showed an N400 only. We interpret the findings within a two-phase language architecture where contextual expectations guide initial access (N400) and precede pragmatic adjustment resulting in reconceptualization (Late Positivity). With masked priming, the N400-difference was reduced for metaphors and vanished for metonymies. This speaks against the direct access view that predicts a facilitating effect for the literal condition only and hence would predict the N400-difference to increase. The results are more consistent with indirect access accounts that argue for facilitation effects for both conditions and consequently for consistent or even smaller N400-amplitude differences. This combined masked priming ERP paradigm therefore yields new insights into the role of literal meaning in the online composition of figurative language.

Semantic properties, aptness, familiarity, conventionality, and interpretive diversity scores for 84 metaphors and similes

For 84 unique topic-vehicle pairs (e.g., knowledge-power), participants produced associated properties for the topics (e.g., knowledge), vehicles (e.g., power), metaphors (knowledge is power), and similes (knowledge is like power). For these properties, we also obtained frequency, saliency, and connotativeness scores (i.e., how much the properties deviated from the denotative or literal meaning). In addition, we examined whether expression type (metaphor vs. simile) impacted the interpretations produced. We found that metaphors activated more salient properties than did similes, but the connotativeness levels for metaphor and simile salient properties were similar. Also, the two types of expressions did not differ across a wide range of measures collected: aptness, conventionality, familiarity, and interpretive diversity scores. Combined with the property lists, these interpretation norms constitute a thorough collection of data about metaphors and similes, employing the same topic-vehicle words, which can be used in psycholinguistic and cognitive neuroscience studies to investigate how the two types of expressions are represented and processed. These norms should be especially useful for studies that examine the online processing and interpretation of metaphors and similes, as well as for studies examining how properties related to metaphors and similes affect the interpretations produced.

The manuscript that we finished: structural separation reduces the cost of complement coercion

Two eye-tracking experiments examined the effects of sentence structure on the processing of complement coercion, in which an event-selecting verb combines with a complement that represents an entity (e.g., began the memo). Previous work has demonstrated that these expressions impose a processing cost, which has been attributed to the need to type-shift the entity into an event in order for the sentence to be interpretable (e.g., began writing the memo). Both experiments showed that the magnitude of the coercion cost was reduced when the verb and complement appeared in separate clauses (e.g., The memo that was begun by the secretary; What the secretary began was the memo) compared with when the constituents appeared together in the same clause. The moderating effect of sentence structure on coercion is similar to effects that have been reported for the processing of 2 other types of semantically complex expressions (inanimate subject-verb integration and metonymy). We propose that sentence structure influences the depth at which complex semantic relationships are computed. When the constituents that create the need for a complex semantic interpretation appear in a single clause, readers experience processing difficulty stemming from the need to detect or resolve the semantic mismatch. In contrast, the need to engage in additional processing is reduced when the expression is established across a clause boundary or other structure that deemphasizes the complex relationship.

Comprehension of metaphors in patients with schizophrenia-spectrum disorders

BACKGROUND

Metaphors, mainly proverbs and idiomatic expressions of ordinary life are commonly used as a model for concretism. Previous studies have shown impaired metaphor comprehension in patients with schizophrenia-spectrum disorders compared to either psychiatric or non-psychiatric control subject. The aim of this study was to detect possible quantitative differences in figurative processing between patients with schizophrenia-spectrum disorders and healthy controls.

METHODS

In order to analyse possible dissociations of different aspects of figurative speech, a range of metaphor tasks was used to distinguish between recognition of familiar metaphors, paraphrasing the meaning of the latter and generating novel metaphors: we used a standard proverb test for conventional metaphors consisting of a multiple-choice and a paraphrasing task, and the Metaphoric Triads Test for the assessment of novel metaphors. We included 40 patients with schizophrenia-spectrum disorders and 43 healthy control subjects.

RESULTS

Our results showed that patients had impaired figurative speech processing regarding novel and conventional metaphors. Associations with cognitive functions were detected. Performance on the paraphrasing task was associated with the severity of negative symptoms.

CONCLUSION

We conclude that patients with schizophrenia-spectrum disorders do exhibit impairments in the recognition and paraphrasing of conventional and the generation of novel metaphors and that some cognitive domains as well the extent of negative symptoms might be associated with these deficits.

Beyond the N400: complementary access to early neural correlates of novel metaphor comprehension using combined electrophysiological and haemodynamic measurements

The simultaneous application of different neuroimaging methods combining high temporal and spatial resolution can uniquely contribute to current issues and open questions in the field of pragmatic language perception. In the present study, comprehension of novel metaphors was investigated using near-infrared spectroscopy (NIRS) combined with the simultaneous acquisition of electroencephalography (EEG)/event-related potentials (ERPs). For the first time, we investigated the effects of figurative language on early electrophysiological markers (P200, N400) and their functional relationship to cortical haemodynamic responses within the language network (Broca's area, Wernicke's area). To this end, 20 healthy subjects judged 120 sentences with respect to their meaningfulness, whereby phrases were either literal, metaphoric, or meaningless. Our results indicated a metaphor-specific P200 reduction and a linear increase of N400 amplitudes from literal over metaphoric to meaningless sentences. Moreover, there were metaphor related effects on haemodynamic responses accessed with NIRS, especially within the left lateral frontal cortex (Broca's area). Significant correlations between electrophysiological and haemodynamic responses indicated that P200 reductions during metaphor comprehension were associated with an increased recruitment of neural activity within left Wernicke's area, indicating a link between variations in neural activity and haemodynamic changes within Wernicke's area. This link may reflect processes related to interindividual differences regarding the ability to classify novel metaphors. The present study underlines the usefulness of simultaneous NIRS measurements in language paradigms - especially for investigating the functional significance of neurophysiological markers that have so far been rarely examined - as these measurements are easily and efficiently realizable and allow for a complementary examination of neural activity and associated metabolic changes in cortical areas.

Differentiating among pragmatic uses of words through timed sensicality judgments

Pragmatic and cognitive accounts of figurative language posit a difference between metaphor and metonymy in terms of underlying conceptual operations. Recently, other pragmatic uses of words have been accounted for in the Relevance Theory framework, such as approximation, described in terms of conceptual adjustment that varies in degree and direction with respect to the case of metaphor. Despite the theoretical distinctions, there is very poor experimental evidence addressing the metaphor/metonymy distinction, and none concerning approximation. Here we used meticulously built materials to investigate the interpretation mechanisms of these three phenomena through timed sensicality judgments. Results revealed that interpreting metaphors and approximations differs from literal interpretation both in accuracy and reaction times, with higher difficulty and costs for metaphors than for approximations. This suggests similar albeit gradual interpretative costs, in line with the latest account of Relevance Theory. Metonymy, on the contrary, almost equates literal comprehension and calls for a theoretical distinction from metaphor. Overall, this work represents a first attempt to provide an empirical basis for a theory-sound and psychologically-grounded taxonomy of figurative and loose uses of language.

ERP evidence for conceptual mappings and comparison processes during the comprehension of conventional and novel metaphors

Cognitive linguists suggest that understanding metaphors requires activation of conceptual mappings between the involved concepts. We tested whether mappings are indeed in use during metaphor comprehension, and what mapping means as a cognitive process with Event-Related Potentials. Participants read literal, conventional metaphorical, novel metaphorical, and anomalous target sentences preceded by primes with related or unrelated mappings. Experiment 1 used sentence-primes to activate related mappings, and Experiment 2 used simile-primes to induce comparison thinking. In the unprimed conditions of both experiments, metaphors elicited N400s more negative than the literals. In Experiment 1, related sentence-primes reduced the metaphor-literal N400 difference in conventional, but not in novel metaphors. In Experiment 2, related simile-primes reduced the metaphor-literal N400 difference in novel, but not clearly in conventional metaphors. We suggest that mapping as a process occurs in metaphors, and the ways in which it can be facilitated by comparison differ between conventional and novel metaphors.

It's hard to offend the college: effects of sentence structure on figurative-language processing

Previous research has given inconsistent evidence about whether familiar metonyms are more difficult to process than literal expressions. In 2 eye-tracking-while-reading experiments, we tested the hypothesis that the difficulty associated with processing metonyms would depend on sentence structure. Experiment 1 examined comprehension of familiar place-for-institution metonyms (e.g., college) when they were an argument of the main verb and showed that they are more difficult to process in a figurative context (e.g., offended the college) than in a literal context (e.g., photographed the college). Experiment 2 demonstrated that when they are arguments of the main verb, familiar metonyms are more difficult to process than frequency-and-length-matched nouns that refer to people (e.g., offended the leader), but that this difficulty was reduced when the metonym appeared as part of an adjunct phrase (e.g., offended the honor of the college). The results support the view that figurative-language processing is moderated by sentence structure. When the metonym was an argument of the verb, the results were consistent with the pattern predicted by the indirect-access model of figurative-language comprehension. In contrast, when the metonym was part of an adjunct phrase, the results were consistent with the pattern predicted by the direct-access model.

Can clouds dance? Part 2: an ERP investigation of passive conceptual expansion

Conceptual expansion, one of the core operations in creative cognition, was investigated in the present ERP study. An experimental paradigm using novel metaphoric, nonsensical and literal phrases was employed where individual differences in conceptual knowledge organization were accounted for by using participants' responses to categorize the stimuli to each condition. The categorization was determined by their judgment of the stimuli on the two defining criteria of creativity: unusualness and appropriateness. Phrases judged as unusual and appropriate were of special interest as they are novel and unfamiliar phrases thought to passively induce conceptual expansion. The results showed a graded N400 modulation for phrases judged to be unusual and inappropriate (nonsense) or unusual and appropriate (conceptual expansion, novel metaphorical) relative to usual and appropriate (literal) phrases. The N400 is interpreted as indexing greater effort to retrieve semantic information and integrate the novel concepts presented through the phrases. Analyses of the later time-window showed an ongoing negativity that was graded in the same manner as the N400. The findings attest to the usefulness of investigating creative cognition using event-related electrophysiology.

Predictability and novelty in literal language comprehension: an ERP study

Linguists have suggested that one mechanism for the creative extension of meaning in language involves mapping, or constructing correspondences between conceptual domains. For example, the sentence, "The clever boys used a cardboard box as a boat," sets up a novel mapping between the concepts cardboard box and boat, while "His main method of transportation is a boat," relies on a more conventional mapping between method of transportation and boat. To examine the electrophysiological signature of this mapping process, electroencephalogram (EEG) was recorded from the scalp as healthy adults read three sorts of sentences: low-cloze (unpredictable) conventional ("His main method of transportation is a boat,"), low-cloze novel mapp'ing ("The clever boys used a cardboard box as a boat,"), and high-cloze (predictable) conventional ("The only way to get around Venice is to navigate the canals in a boat,"). Event-related brain potentials (ERPs) were time-locked to sentence final words. The novel and conventional conditions were matched for cloze probability (a measure of predictability based on the sentence context), lexical association between the sentence frame and the final word (using latent semantic analysis), and other factors known to influence ERPs to language stimuli. The high-cloze conventional control condition was included to compare the effects of mapping conventionality to those of predictability. The N400 component of the ERPs was affected by predictability but not by conventionality. By contrast, a late positivity was affected both by the predictability of sentence final words, being larger for words in low-cloze contexts that made target words difficult to predict, and by novelty, as words in the novel condition elicited a larger positivity 700-900ms than the same words in the (cloze-matched) conventional condition.

Electrophysiological insights into the processing of nominal metaphors

We used event-related potentials (ERPs) to examine the time-course of processing metaphorical and literal sentences in the brain. ERPs were measured to sentence-final (Experiment 1) and mid-sentence (Experiment 2) critical words (CWs) as participants read and made plausibility judgments about familiar nominal metaphors ("A is a B") as well as literal and semantically anomalous sentences of the same form. Unlike the anomalous words, which evoked a robust N400 effect (on the CW in experiments 1 and 2 as well as on the sentence-final word in experiment 2), CWs in the metaphorical, relative to the literal, sentences only evoked an early, localized N400 effect that was over by 400ms after CW onset, suggesting that, by this time, their metaphorical meaning had been accessed. CWs in the metaphorical sentences also evoked a significantly larger LPC (Late Positive Component) than in the literal sentences. We suggest that this LPC reflected additional analysis that resolved a conflict between the implausibility of the literal sentence interpretation and the match between the metaphorical meaning of the CW, the context and stored information within semantic memory, resulting from early access to both literal and figurative meanings of the CWs.