title: Beyond words: Pragmatic inference in behavioral variant of frontotemporal degeneration.
abstract: When the message of a speaker goes beyond the literal or logical meaning of the sentences used, a pragmatic inference is required to understand the complete meaning of an utterance. Here we study one example of pragmatic inference, called scalar implicature. Such an inference is required when a weaker term "some" is used in a sentence like "Some of the students passed the exam" because the speaker presumably had a reason not to use a stronger term like "all". We investigated the comprehension of scalar implicatures in a group of 17 non-aphasic patients with behavioral variant frontotemporal degeneration (bvFTD) in order to test the contribution of non-linguistic decision-making ability and the role of prefrontal cortex in supporting the computation of pragmatic inferences. The results of two experiments point to a deficit in producing alternative interpretations beyond a logical reading. bvFTD patients thus prefer the narrowly literal or logical interpretation of a scalar term when they must generate a possible alternative interpretation by themselves, but patients prefer a pragmatic reading when offered a choice between the logical and the pragmatic interpretation of the same sentence. An imaging analysis links bvFTD patients' spontaneous tendency toward a narrowly logical interpretation with atrophy in ventromedial prefrontal cortex. Our findings are consistent with the pragmatic tolerance hypothesis, which proposes that difficulty generating alternative interpretations of an utterance, rather than a frank inability to compute an inference, affects the comprehension of a scalar term.
authors.affiliation: University of Pennsylvania Perelman School of Medicine, Penn Frontotemporal Degeneration Center, Philadelphia, 19104 PA, USA. Electronic address: spotorno@mail.med.upenn.edu.
authors.forename: Nicola
authors.initials: N
authors.lastname: Spotorno
authors.affiliation: University of Pennsylvania Perelman School of Medicine, Penn Frontotemporal Degeneration Center, Philadelphia, 19104 PA, USA.
authors.forename: Corey T
authors.initials: CT
authors.lastname: McMillan
authors.affiliation: University of Pennsylvania Perelman School of Medicine, Penn Frontotemporal Degeneration Center, Philadelphia, 19104 PA, USA.
authors.forename: Katya
authors.initials: K
authors.lastname: Rascovsky
authors.affiliation: University of Pennsylvania Perelman School of Medicine, Penn Frontotemporal Degeneration Center, Philadelphia, 19104 PA, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Irwin
authors.affiliation: University of Pennsylvania, Department of Linguistics, Philadelphia, 19104 PA, USA.
authors.forename: Robin
authors.initials: R
authors.lastname: Clark
authors.affiliation: University of Pennsylvania Perelman School of Medicine, Penn Frontotemporal Degeneration Center, Philadelphia, 19104 PA, USA. Electronic address: mgrossma@mail.med.upenn.edu.
authors.forename: Murray
authors.initials: M
authors.lastname: Grossman
mesh_terms: D032882:Comprehension / Q000502:physiology*; D003657:Decision Making / Q000502:physiology; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000503:physiopathology*
keywords: Pragmatic tolerance; Scalar implicature; bvFTD