PhD Thesis: Linguistic Creativity and Formal Thought Disorder in Schizophrenia
Doctoral thesis (PhD), Manchester Metropolitan University (2024). This work develops operational definitions of linguistic creativity and formal thought disorder (FTD), introduces the 4TD Framework, and examines these constructs using experimental psycholinguistics and corpus methods.
View thesis record (MMU e-space) Download PDFRelated on this site
Abstract (summary)
The thesis argues that both linguistic creativity and formal thought disorder are heterogeneously expressed and hard to define. It develops operational definitions by integrating historical and contemporary accounts of FTD with approaches to testing creative linguistic ability in schizophrenia populations.
It introduces the 4TD Framework, situating descriptions of FTD across linguistic levels (phonology, morphology, syntax, semantics, pragmatics) and reframing FTD in terms of grammar, word selection, thought completion, and discourse tracking. It also proposes that linguistic creativity in schizophrenia is selectively constrained by symptoms and intellectual ability, rather than uniformly impaired.
Methods and contributions
Experimental component: an original metaphor creation task designed by adapting elements from existing tasks for use with a schizophrenia cohort.
Corpus component: a small specialised spoken-language corpus designed for analysis of abstract discussion and creativity in schizophrenia, with an emphasis on ethical accessibility and documentation.
For dataset access and documentation, see the DAIS-C dataset page above (hosted via UK Data Service ReShare).
Key findings (high-level)
The literature review supports the view that figurative language comprehension is compromised in schizophrenia. Quantitative analyses suggest grammatical disturbances in everyday speech are more prominent in schizophrenia speakers, and may lie on a continuum with typical speech—supporting a dimensional approach to assessing FTD.
The thesis also reports that schizophrenia speakers may over-involve emotionally salient or personally concerned topics when discussing abstract concepts, and argues for greater emphasis on grammatical features in future work.