Abstract
The human microbiota —the collection of microorganisms living on and inside the body—plays a fundamental role in human health. While diet, genetics, and environment strongly shape microbiota composition, social interactions may also influence the microbial communities associated with the human body. Intimate kissing is a widespread human behaviour that involves close contact and exchange of saliva, providing an opportunity for direct microbial transmission between individuals. This article explores the hypothesis that intimate kissing can induce a reinforcing cycle – a positive feedback loop - that shapes and stabilizes the oral microbiota of partners over time. Neurobiological pathways, including the gut microbiota–brain axis, might reinforce this feedback loop. Current evidence is synthesized and a study design outlined to explore how kissing may lead to sustained microbial sharing and potential systemic effects.
| Original language | English |
|---|---|
| Article number | 106777 |
| Pages (from-to) | 1-12 |
| Number of pages | 12 |
| Journal | Evolution and Human Behavior |
| Volume | 47 |
| Issue number | 1 |
| Early online date | 31 Oct 2025 |
| DOIs | |
| Publication status | Published - Jan 2026 |
Bibliographical note
Publisher Copyright:© 2025 The Author
Funding
The author gratefully acknowledges Gordon Getty and the Board of Directors of the Gruter Institute for Law and Behavioral Research for the invitation to present and discuss the hypothesis developed in this paper at the KissCon II conference in San Francisco, February 2025. Appreciation is also extended to the anonymous reviewer for providing valuable suggestions that substantially improved the manuscript.
| Funders | Funder number |
|---|---|
| Gordon Getty | |
| Gruter Institute for Law |