Abstract
What makes a proposition true or false has traditionally played an essential role in philosophical and linguistic theories of meaning. A comprehensive neurobiological theory of language must ultimately be able to explain the combined contributions of real-world truth-value and discourse context to sentence meaning. This fMRI study investigated the neural circuits that are sensitive to the propositional truth-value of sentences about counterfactual worlds, aiming to reveal differential hemispheric sensitivity of the inferior prefrontal gyri to counterfactual truth-value and real-world truth-value. Participants read true or false counterfactual conditional sentences ("If N.A.S.A. had not developed its Apollo Project, the first country to land on the moon would be Russia/America") and real-world sentences ("Because N.A.S.A. developed its Apollo Project, the first country to land on the moon has been America/Russia") that were matched on contextual constraint and truth-value. ROI analyses showed that whereas the left BA 47 showed similar activity increases to counterfactual false sentences and to real-world false sentences (compared to true sentences), the right BA 47 showed a larger increase for counterfactual false sentences. Moreover, whole-brain analyses revealed a distributed neural circuit for dealing with propositional truth-value. These results constitute the first evidence for hemispheric differences in processing counterfactual truth-value and real-world truth-value, and point toward additional right hemisphere involvement in counterfactual comprehension.
Highlights
Language is a computationally remarkable, uniquely human system, not to mention our principal and most efficient means of communication
The current fMRI study aimed to address the following question: Are the LIFG and RIFG differentially engaged in balancing the recruitment of information in long-term memory with the online construction of a discourse-relevant and contextualized interpretation? and more generally, what brain regions are sensitive to sentence truth-value? This study aims to answer those questions in the context of counterfactual sentence comprehension, by directly comparing the neural processing consequences of sentences that are false with regard to a hypothetical, counterfactual world with those of sentences that are false with regard to the current real-world knowledge
This difference was driven mainly by a large response to counterfactual false sentences, which was larger than the response to real-world false sentences (F(1,23) = 3.59, p = .002), while the responses to counterfactual true and real-world true sentences did not differ (F(1,23) = 1.06, p = .31)
Summary
Language is a computationally remarkable, uniquely human system, not to mention our principal and most efficient means of communication. Conditions that make a proposition true or false have traditionally played an essential role in philosophical and linguistic theories of meaning (e.g., Montague, 1974; Tarski, 1944). One prominent example of this cognitive ability is counterfactual reasoning about what is false as if it were true (e.g., “If China had entered the Vietnam war, ...”), which is pervasive in everyday life (e.g., Byrne, 2002; Kahneman & Miller, 1986; Roese, 1997), and considered one of the According to cognitive theories of text comprehension (e.g., Gernsbacher, 1997; Kintsch, 1988; Myers and O'Brien, 1998), comprehension of counterfactual language requires the suppression or inhibition of automatically activated world knowledge. All information in memory that is related to unfolding linguistic input is initially activated, and this network of co-activations is subsequently pruned so that only the information that is most relevant to the
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
