Embedding in language and in thinking: A double dissociation in aphasia and aTOMia

EasyChair Preprint 6454

Abstract

We examined a fundamental question about the relation between language and thought: Whether a dissociation can be detected between language and thought by examining whether the ability to embed thoughts (as part of theory of mind, TOM) relies on the ability to create and comprehend syntactic embedding structures that express these states (e.g., "Dana thought that the world is flat").

We tested four patients with agrammatic aphasia, which involved a syntactic deficit in embedding, identified using five comprehension, production, and grammaticality-judgment syntactic tasks from the BAFLA battery (Friedmann, 1998). Four others had aTOMia (TOM deficit), diagnosed using 16 stories and 4 cartoons from the aTOMia battery, assessing second-order theory of mind abilities (Balaban et al., 2016).

The results showed a double dissociation between embedding in language and embedding in thinking. The four participants with a TOM deficit performed very well on the comprehension and production of syntactic embedding (95%) while their performance on the aTOMia battery was poor (36%). In contrast, the participants with agrammatic aphasia were able to represent second-order mental states (90%) but still showed a significant impairment in the comprehension and production of syntactic embedding (46%).

This double dissociation indicates that once the abilities of linguistic embedding and mental embedding are acquired, they are independent and each can be compromised independently. Our study indicates that individuals with aphasia can retain the ability to think about other people’s thoughts even when they lose syntactic abilities; one can lose the ability to speak about something, but still be able to reflect about it and understand it. This indicates that at least in this domain thought is not completely dependent on language.

Keyphrases: Tom, aphasia, embedding, language comprehension, language production, pragmatics, syntax

@booklet{EasyChair:6454,
  author    = {Maayan Gabso-Rajuan and Noga Balaban and Naama Friedmann},
  title     = {Embedding in language and in thinking: A double dissociation in aphasia and aTOMia},
  howpublished = {EasyChair Preprint 6454},
  year      = {EasyChair, 2021}}