Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: Lundin, Nancy B, Todd, Peter M, Jones, Michael N, Avery, Johnathan E, O’Donnell, Brian F, Hetrick, William P
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2020
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
_version_ 1783569771220959232
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
work_keys_str_mv AT lundinnancyb semanticsearchinpsychosismodelinglocalexploitationandglobalexploration
AT toddpeterm semanticsearchinpsychosismodelinglocalexploitationandglobalexploration
AT jonesmichaeln semanticsearchinpsychosismodelinglocalexploitationandglobalexploration
AT averyjohnathane semanticsearchinpsychosismodelinglocalexploitationandglobalexploration
AT odonnellbrianf semanticsearchinpsychosismodelinglocalexploitationandglobalexploration
AT hetrickwilliamp semanticsearchinpsychosismodelinglocalexploitationandglobalexploration