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Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration
Impairments in category verbal fluency task (VFT) performance have been widely documented in psychosis. These deficits may be due to disturbed “cognitive foraging” in semantic space, in terms of altered salience of cues that influence individuals to search locally within a subcategory of semanticall...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418865/ https://www.ncbi.nlm.nih.gov/pubmed/32803160 http://dx.doi.org/10.1093/schizbullopen/sgaa011 |
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author | Lundin, Nancy B Todd, Peter M Jones, Michael N Avery, Johnathan E O’Donnell, Brian F Hetrick, William P |
author_facet | Lundin, Nancy B Todd, Peter M Jones, Michael N Avery, Johnathan E O’Donnell, Brian F Hetrick, William P |
author_sort | Lundin, Nancy B |
collection | PubMed |
description | Impairments in category verbal fluency task (VFT) performance have been widely documented in psychosis. These deficits may be due to disturbed “cognitive foraging” in semantic space, in terms of altered salience of cues that influence individuals to search locally within a subcategory of semantically related responses (“clustering”) or globally between subcategories (“switching”). To test this, we conducted a study in which individuals with schizophrenia (n = 21), schizotypal personality traits (n = 25), and healthy controls (n = 40) performed VFT with “animals” as the category. Distributional semantic model Word2Vec computed cosine-based similarities between words according to their statistical usage in a large text corpus. We then applied a validated foraging-based search model to these similarity values to obtain salience indices of frequency-based global search cues and similarity-based local cues. Analyses examined whether diagnosis predicted VFT performance, search strategies, cue salience, and the time taken to switch between vs search within clusters. Compared to control and schizotypal groups, individuals with schizophrenia produced fewer words, switched less, and exhibited higher global cue salience, indicating a selection of more common words when switching to new clusters. Global cue salience negatively associated with vocabulary ability in controls and processing speed in schizophrenia. Lastly, individuals with schizophrenia took a similar amount of time to switch to new clusters compared to control and schizotypal groups but took longer to transition between words within clusters. Findings of altered local exploitation and global exploration through semantic memory provide preliminary evidence of aberrant cognitive foraging in schizophrenia. |
format | Online Article Text |
id | pubmed-7418865 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-74188652020-08-13 Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration Lundin, Nancy B Todd, Peter M Jones, Michael N Avery, Johnathan E O’Donnell, Brian F Hetrick, William P Schizophr Bull Open Regular Article Impairments in category verbal fluency task (VFT) performance have been widely documented in psychosis. These deficits may be due to disturbed “cognitive foraging” in semantic space, in terms of altered salience of cues that influence individuals to search locally within a subcategory of semantically related responses (“clustering”) or globally between subcategories (“switching”). To test this, we conducted a study in which individuals with schizophrenia (n = 21), schizotypal personality traits (n = 25), and healthy controls (n = 40) performed VFT with “animals” as the category. Distributional semantic model Word2Vec computed cosine-based similarities between words according to their statistical usage in a large text corpus. We then applied a validated foraging-based search model to these similarity values to obtain salience indices of frequency-based global search cues and similarity-based local cues. Analyses examined whether diagnosis predicted VFT performance, search strategies, cue salience, and the time taken to switch between vs search within clusters. Compared to control and schizotypal groups, individuals with schizophrenia produced fewer words, switched less, and exhibited higher global cue salience, indicating a selection of more common words when switching to new clusters. Global cue salience negatively associated with vocabulary ability in controls and processing speed in schizophrenia. Lastly, individuals with schizophrenia took a similar amount of time to switch to new clusters compared to control and schizotypal groups but took longer to transition between words within clusters. Findings of altered local exploitation and global exploration through semantic memory provide preliminary evidence of aberrant cognitive foraging in schizophrenia. Oxford University Press 2020-01 2020-04-20 /pmc/articles/PMC7418865/ /pubmed/32803160 http://dx.doi.org/10.1093/schizbullopen/sgaa011 Text en © The Author(s) 2020. Published by Oxford University Press on behalf of the University of Maryland's school of medicine, Maryland Psychiatric Research Center. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | Regular Article Lundin, Nancy B Todd, Peter M Jones, Michael N Avery, Johnathan E O’Donnell, Brian F Hetrick, William P Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration |
title | Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration |
title_full | Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration |
title_fullStr | Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration |
title_full_unstemmed | Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration |
title_short | Semantic Search in Psychosis: Modeling Local Exploitation and Global Exploration |
title_sort | semantic search in psychosis: modeling local exploitation and global exploration |
topic | Regular Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418865/ https://www.ncbi.nlm.nih.gov/pubmed/32803160 http://dx.doi.org/10.1093/schizbullopen/sgaa011 |
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