Evidence for role-neutral initial processing of metaphors

Do metaphorical sharks bite? Simulation and abstraction in metaphor processing

In a metaphor such as lawyers are sharks, the concept lawyers, which is the metaphor topic, and the concept sharks, which is the metaphor vehicle, interact to produce a figurative meaning such that lawyers are predatory. Some theorists argue that sensorimotor properties of the vehicle are the basis of metaphor comprehension. Accordingly, the metaphor lawyers are sharks is processed as a simulation in which bodily actions related to sharks are accessed (e.g., sharks chasing prey). In contrast, the long-standing assumption is that metaphors are processed as abstractions with no role played by sensorimotor properties. From this theoretical perspective, abstract characteristics of sharks (e.g., vicious, predatory) are argued to be the core properties involved in metaphor processing. Here, we juxtapose these two opposing views of metaphor processing using cross-modal lexical priming. We find evidence that low-familiar metaphors (e.g., highways are snakes) prime bodily-action associates (i.e., slither) but not abstraction associates (i.e., danger), and are hence processed via simulation, whereas high-familiar metaphors (e.g., lawyers are sharks) prime abstraction associates (i.e., killer) but not bodily-action associates (i.e., bite) and are therefore processed via abstraction. The results align with views of cognition and language that posit the presence of both embodied and abstract representations.

On understanding creative language: The late positive complex and novel metaphor comprehension

Novel metaphoric sentences have repeatedly evoked larger N400 amplitudes than literal sentences, while investigations of the late positive complex (LPC) have brought inconsistent results, with reports of both increased and reduced amplitudes. In two experiments, we examined novel metaphor comprehension in Polish, using the same set of literal, novel metaphoric, and anomalous sentences. The first aim of the study was to test whether novel metaphors would evoke larger or smaller late positivity complex (LPC) amplitudes compared to literal and anomalous sentences. Some earlier studies have shown that whether increased LPC amplitudes are observed or not may be related to the task participants are asked to perform, with explicit acceptability judgments being more likely to evoke the LPC effect. The second aim of the study was, thus, to test whether the observed LPC pattern would be the same across two tasks, the semantic decision task (Experiment 1) and the reading task (Experiment 2). Our results replicated the N400 effect observed in earlier studies on metaphor in both experiments. Most importantly, a reduction in late positivity to novel metaphors relative to anomalous sentences was found in both experiments. Additionally, this difference was broadly distributed over parietal sites in Experiment 1, and clearly left-lateralized in Experiment 2, which might imply differences in the involvement of recollection and semantic processes. Overall, these results seem to indicate that both conventionality and task demands modulate the LPC pattern.

Automatic metaphor processing in adults with Asperger syndrome: a metaphor interference effect task

This paper investigates automatic processing of novel metaphors in adults with Asperger Syndrome (AS) and typically developing controls. We present an experiment combining a semantic judgment task and a recognition task. Four types of sentences were compared: Literally true high-typical sentences, literally true low-typical sentences, apt metaphors, and scrambled metaphors (literally false sentences which are not readily interpretable as metaphors). Participants were asked to make rapid decisions about the literal truth of such sentences. The results revealed that AS and control participants showed significantly slower RTs for metaphors than for scrambled metaphors and made more mistakes in apt metaphoric sentences than in scrambled metaphors. At the same time, there was higher recognition of apt metaphors compared with scrambled metaphors. The findings indicate intact automatic metaphor processing in AS and replicate previous findings on automatic metaphor processing in typically developing individuals.

Structure-mapping in metaphor comprehension

Metaphor has a double life. It can be described as a directional process in which a stable, familiar base domain provides inferential structure to a less clearly specified target. But metaphor is also described as a process of finding commonalities, an inherently symmetric process. In this second view, both concepts may be altered by the metaphorical comparison. Whereas most theories of metaphor capture one of these aspects, we offer a model based on structure-mapping that captures both sides of metaphor processing. This predicts (a) an initial processing stage of symmetric alignment; and (b) a later directional phase in which inferences are projected to the target. To test these claims, we collected comprehensibility judgments for forward (e.g., "A rumor is a virus") and reversed ("A virus is a rumor") metaphors at early and late stages of processing, using a deadline procedure. We found an advantage for the forward direction late in processing, but no directional preference early in processing. Implications for metaphor theory are discussed.

Nonintentional analogical inference in text comprehension

We present findings suggesting that analogical inference processes can play a role in fluent comprehension and interpretation. Participants were found to use information from a prior relationally similar example in understanding the content of a later example, but they reported that they were not aware of having done so. These inference processes were sensitive to structural mappings between the two instances, ruling out explanations based solely on more general kinds of activation, such as priming. Reading speed measures were consistent with the possibility that these inferences had taken place during encoding of the target rather than during the later recognition test. These findings suggest that analogical mapping, though often viewed as an explicit deliberative process, can sometimes operate without intent or even awareness.

Neural correlates of metaphor processing in schizophrenia

OBJECTIVE

A main feature of schizophrenic thought and language disturbance is concretism, the inability to understand the figurative meaning of proverbs and metaphors. Although this is routinely tested during clinical interview, its neural basis is unknown.

METHOD

We investigated processing of metaphoric sentences with functional magnetic resonance imaging (fMRI) in 12 patients with schizophrenia and 12 control subjects. Stimuli consisted of 60 novel short sentences with either metaphoric or literal meaning presented visually, intersparsed by a low level baseline (grey background). Subjects read these sentences silently and judged by button press whether they had a positive or negative connotation.

RESULTS

Reading metaphors in contrast to literal sentences revealed signal changes in the left inferior frontal gyrus in the control subjects (BA 45/47) and an area 3 cm dorsal to that in the patients (BA 45). Only activation in this area was negatively correlated with the severity of concretism rated with the PANSS. Comparison between groups for the contrast metaphors vs. low level baseline revealed stronger signal changes in the control group in the right superior/middle temporal gyrus (BA 39) and the left inferior frontal gyrus (BA 45) in the patients.

CONCLUSIONS

The results in the control subjects are in line with studies showing an involvement of the left inferior frontal and right lateral temporal cortex during context processing. Failure to recruit these areas in the patients may underlie schizophrenic concretism.

The Career of Metaphor

A central question in metaphor research is how metaphors establish mappings between concepts from different domains. The authors propose an evolutionary path based on structure-mapping theory. This hypothesis--the career of metaphor--postulates a shift in mode of mapping from comparison to categorization as metaphors are conventionalized. Moreover, as demonstrated by 3 experiments, this processing shift is reflected in the very language that people use to make figurative assertions. The career of metaphor hypothesis offers a unified theoretical framework that can resolve the debate between comparison and categorization models of metaphor. This account further suggests that whether metaphors are processed directly or indirectly, and whether they operate at the level of individual concepts or entire conceptual domains, will depend both on their degree of conventionality and on their linguistic form.

ERP and behavioral evidence of individual differences in metaphor comprehension

In two experiments, we examined individual differences in metaphor processing. In Experiment 1, the subjects judged the literal truth of literal, metaphorical, and scrambled sentences. Overall, metaphors were more difficult to judge as false, in comparison with scrambled controls, suggesting that the metaphorical meaning was being processed automatically. However, there were individual differences in that high-IQ subjects showed more interference. These effects were reflected in ERP amplitude differences at the onset of N400 and after the response. In Experiment 2, the subjects completed IQ tests and a series of working memory tests and then rated and interpreted the same set of metaphors. The results showed that IQ was correlated with working memory capacity and that low-IQ subjects had similar ratings but poorer quality interpretations than did high-IQ subjects. The results were most consistent with a constraint satisfaction approach to metaphor comprehension.

The psycholinguistics of metaphor

Can lawyers be sharks, can jobs literally be jails, and can dogs fly across lawns? Such metaphors create novel categories that enable us to characterize the topic of interest. These novel metaphorical categories are special in that they are based on outstanding exemplars of those categories, and they borrow the exemplar's name for use as the category names. Thus 'shark' can be taken as a metaphor for any vicious and predatory being. Contemporary research reveals how people can create and understand such metaphors in ordinary conversation, and suggests that we understand metaphorical meanings as quickly and automatically as we understand literal meanings.

Conceptual integration and metaphor: an event-related potential study

Event-related brain potentials (ERPs) were recorded from 18 normal adults as they read sentences that ended with words used literally, metaphorically, or in an intermediate literal mapping condition. In the latter condition, the literal sense of the word was used in a way that prompted readers to map conceptual structure from a different domain. ERPs measured from 300 to 500 msec after the onset of the sentence-final words differed as a function of metaphoricity: Literal endings elicited the smallest N400, metaphors the largest N400, whereas literal mappings elicited an N400 of intermediate amplitude. Metaphoric endings also elicited a larger posterior positivity than did either literal or literal mapping words. Consistent with conceptual blending theory, the results suggest that the demands of conceptual integration affect the difficulty of both literal and metaphorical language.

Topic-vehicle interaction in metaphor comprehension

Property comparison models of metaphor comprehension assume that the topic and vehicle terms in metaphors are both understood to be referring to their conventional literal referents. In contrast, the interactive property attribution model (Glucksberg, McGlone, & Manfredi, 1997) assumes that the vehicle is understood to be referring to a metaphoric category that includes the topic's literal referent as a member. A priming paradigm was used to test the implications of these different models. Prior to interpreting a metaphor, participants read (1) the topic or vehicle concept alone, (2) a sentence ascribing a metaphor-relevant property to one concept, or (3) a sentence ascribing a metaphor-irrelevant property to one concept. All of the prime types facilitated metaphor comprehension with the exception of sentences ascribing metaphor-irrelevant properties to vehicles. The failure of these sentences (but not their topic counterparts) to facilitate metaphor comprehension is attributable to their priming an inappropriate literal interpretation of the vehicle term. These results are consistent with the claim that irrelevant information is suppressed during language comprehension (Gernsbacher, 1990) and support the interactive property attribution model.