Neural substrates of sarcasm: A functional magnetic-resonance imaging study

Abstract

The understanding of sarcasm reflects a complex process, which involves recognizing the beliefs of the speaker. There is a clear association between deficits in mentalizing, which is the ability to understand other people's behavior in terms of their mental state, and the understanding of sarcasm in individuals with autistic spectrum disorders. This suggests that mentalizing is important in pragmatic non-literal language comprehension. To highlight the neural substrates of sarcasm, 20 normal adult volunteers underwent functional magnetic-resonance imaging. We used scenario-reading tasks, in which sentences describing a certain situation were presented, followed by the protagonist's comments regarding that situation. Depending on the situation, the semantic content of the comments was classified as sarcastic, non-sarcastic, or contextually unconnected. As the combination of the first and second sentences represented discourse-level information that was not encoded in the individual sentences, sarcasm detection was represented as the differential activation induced by the second sentences. Sarcasm detection activated the left temporal pole, the superior temporal sulcus, the medial prefrontal cortex, and the inferior frontal gyrus (Brodmann's area [BA] 47). The left BA 47 was activated more prominently by sarcasm detection than by the first sentence. These findings indicate that the detection of sarcasm recruits the medial prefrontal cortex, which is part of the mentalizing system, as well as the neural substrates involved in reading sentences. The left BA 47 might therefore be where mentalizing and language processes interact during sarcasm detection.

Neural evidence that utterance-processing entails mentalizing: The case of irony

“…One is that the vignettes and their target utterances are almost invariably short, ranging from two to at most four sentences (Eviatar and Just, 2006;Rapp et al, 2010;Shibata et al, 2010;Uchiyama et al, 2006Uchiyama et al, , 2011Wakusawa et al, 2007;Wang et al, 2006). Arguably, such brevity gives a participant a limited amount of time to appreciate the background of a story and its eventual irony (as in 2a above).…”

“…In two studies (e.g., Shibata et al, 2010;Wakusawa et al, 2007), ironic versus literal stories are not designed from common contexts. In three other studies (Eviatar and Just, 2006;Uchiyama et al, 2006;Wang et al, 2006), as Rapp et al (2010) point out, Ironic and Literal conditions are not directly compared. For example, Uchiyama et al's (2006) sarcasm-detection measure was determined by contrasting, on the one hand, the sarcastic and the non-sarcastic remarks together and, on the other, a control sentence that was "unconnected."…”

“…There are currently seven studies that employ functional neuroimaging techniques to investigate irony processing on healthy participants (Eviatar and Just, 2006;Rapp et al, 2010;Shibata et al, 2010;Uchiyama et al, 2006Uchiyama et al, , 2011Wakusawa et al, 2007;Wang et al, 2006; see Table 1 for a description and summary of the prior neuroimaging studies). Remarkably, no single study reports extensive activity in the ToM network in the way that neural ToM tasks do (cf.…”

Where in the brain is nonliteral language? A coordinate-based meta-analysis of functional magnetic resonance imaging studies

“…The strongest and largest cluster was found in the left inferior frontal gyrus in regions equivalent to Brodmann area 13/45 with extension into the middle frontal gyrus (Brodmann area 9). The second strongest cluster was located in the left middle/superior temporal gyrus (Brodmann area 22) with contributions from studies on irony (Shibata et al, 2010;Uchiyama et al, 2006), metaphor (Ahrens et al, 2007;, idioms (Boulenger et al, 2009Zempleni et al, 2007), and metonymy .…”

“…Subsequently, more than 15 additional fMRI metaphor studies followed (Table 1). The first fMRI studies on ironic expressions were published in 2006 (Eviatar and Just, 2006;Uchiyama et al, 2006;Wang et al, 2006a), followed by work on idioms (Zempleni, 2006) and metonymy . In their first study, Rapp and colleagues determined that the anterior-inferior part of the left IFG in particular plays a key role in disentangling non-literal meanings Rapp et al, 2004).…”