Abstract

The function of dreams is a longstanding scientific research question. Simulation theories of dream function, which are based on the premise that dreams represent evolutionary past selective pressures and fitness improvement through modified states of consciousness, have yet to be tested in cross-cultural populations that include small-scale forager societies. Here, we analyze dream content with cross-cultural comparisons between the BaYaka (Rep. of Congo) and Hadza (Tanzania) foraging groups and Global North populations, to test the hypothesis that dreams in forager groups serve a more effective emotion regulation function due to their strong social norms and high interpersonal support. Using a linear mixed effects model we analyzed 896 dreams from 234 individuals across these populations, recorded using dream diaries. Dream texts were processed into four psychosocial constructs using the Linguistic Inquiry and Word Count (LIWC-22) dictionary. The BaYaka displayed greater community-oriented dream content. Both the BaYaka and Hadza exhibited heightened threat dream content, while, at the same time, the Hadza demonstrated low negative emotions in their dreams. The Global North Nightmare Disorder group had increased negative emotion content, and the Canadian student sample during the COVID-19 pandemic displayed the highest anxiety dream content. In conclusion, this study supports the notion that dreams in non-clinical populations can effectively regulate emotions by linking potential threats with non-fearful contexts, reducing anxiety and negative emotions through emotional release or catharsis. Overall, this work contributes to our understanding of the evolutionary significance of this altered state of consciousness.

Details

Title
Evidence for an emotional adaptive function of dreams: a cross-cultural study
Author
Samson, David R. 1 ; Clerget, Alice 2 ; Abbas, Noor 3 ; Senese, Jeffrey 3 ; Sarma, Mallika S. 4 ; Lew-Levy, Sheina 5 ; Mabulla, Ibrahim A. 6 ; Mabulla, Audax Z. P. 6 ; Miegakanda, Valchy 7 ; Borghese, Francesca 2 ; Henckaerts, Pauline 2 ; Schwartz, Sophie 2 ; Sterpenich, Virginie 2 ; Gettler, Lee T. 8 ; Boyette, Adam 5 ; Crittenden, Alyssa N. 9 ; Perogamvros, Lampros 10 

 University of Toronto, Sleep and Human Evolution Lab, Mississauga, Canada (GRID:grid.17063.33) (ISNI:0000 0001 2157 2938); University of Toronto, Department of Anthropology, Mississauga, Canada (GRID:grid.17063.33) (ISNI:0000 0001 2157 2938) 
 University of Geneva, Department of Basic Neurosciences, Geneva, Switzerland (GRID:grid.8591.5) (ISNI:0000 0001 2322 4988) 
 University of Toronto, Sleep and Human Evolution Lab, Mississauga, Canada (GRID:grid.17063.33) (ISNI:0000 0001 2157 2938) 
 Johns Hopkins University, School of Medicine, Baltimore, USA (GRID:grid.21107.35) (ISNI:0000 0001 2171 9311) 
 Max Planck Institute for Evolutionary Anthropology, Department of Human Behavior, Ecology and Culture, Leipzig, Germany (GRID:grid.419518.0) (ISNI:0000 0001 2159 1813) 
 University of Dar es Salaam, Department of Archaeology and Heritage, Institute of Resource Assessment, Dar es Salaam, Tanzania (GRID:grid.8193.3) (ISNI:0000 0004 0648 0244) 
 Laboratoire National de Santé Publique, Brazzaville, Republic of the Congo (GRID:grid.463270.4) 
 University of Notre Dame, Department of Anthropology, Notre Dame, USA (GRID:grid.131063.6) (ISNI:0000 0001 2168 0066) 
 University of Nevada, Department of Anthropology, Las Vegas, USA (GRID:grid.266818.3) (ISNI:0000 0004 1936 914X) 
10  University of Geneva, Department of Basic Neurosciences, Geneva, Switzerland (GRID:grid.8591.5) (ISNI:0000 0001 2322 4988); University Hospitals of Geneva, Department of Psychiatry, Center for Sleep Medicine, Geneva, Switzerland (GRID:grid.150338.c) (ISNI:0000 0001 0721 9812); Center for Sleep Medicine, Department of Psychiatry, 1226 Thônex, Switzerland (GRID:grid.150338.c) 
Pages
16530
Publication year
2023
Publication date
2023
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2871494396
Copyright
© Springer Nature Limited 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.