Evidence for an emotional adaptive function of dreams: a cross-cultural study.
David R. Samson, Alice Clerget, Noor H. Abbas, Jeffrey D. Senese, Mallika S. Sarma, Sheina Lew‐Levy, Ibrahim A. Mabulla, Audax Z P Mabulla, Valchy Miegakanda, Francesca Borghese, Pauline Henckaerts, Sophie Schwartz, Virginie Sterpenich, Lee T. Gettler, Adam H. Boyette, Alyssa N. Crittenden, Lampros Perogamvros
Scientific Reports October 2, 2023 DOI: 10.1038/s41598-023-43319-z (opens in new tab) via PubMed
Summary
AI-generated from the abstractDreams in two small-scale foraging societies—the BaYaka of the Republic of Congo and the Hadza of Tanzania—show patterns that support an emotion regulation function, contrasting with dreams in Global North populations. Analyzing 896 dreams from 234 individuals, the BaYaka had more community-oriented content, while both foraging groups showed heightened threat dream content. Yet the Hadza displayed low negative emotions in their dreams, suggesting a link between potential threats and non-fearful contexts that reduces anxiety. In comparison, a Global North Nightmare Disorder group had increased negative emotion content, and a Canadian student sample during the COVID-19 pandemic showed the highest anxiety dream content. These findings support the idea that dreams can effectively regulate emotions through catharsis, contributing to understanding the evolutionary significance of dreaming.
Study at a glance
| Characteristics | Cross-cultural comparative study Peer reviewed |
|---|---|
| Sample size | 234 |
| Population | BaYaka (Republic of Congo) and Hadza (Tanzania) foragers, plus Global North populations (Nightmare Disorder group and Canadian students during COVID-19 pandemic) |
| Key finding | Dreams in foraging groups, particularly the Hadza, link threat content with low negative emotion, supporting an emotion regulation function, unlike Global North populations where threat dreams are associated with higher negative emotion. |
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.