Book Notes
The Science of Kissing by Sheril Kirshenbaum — review and summary
Sheril Kirshenbaum asks what is actually happening when people kiss — biologically, psychologically, and culturally — and finds that the answers are more interesting and more complex than the question first suggests.
Sheril Kirshenbaum is a science writer with a background in marine biology and science policy. The Science of Kissing is her exploration of a very specific biological and cultural behaviour: the kiss. What is it for? Why do humans do it? What is happening in the brain and body when it occurs? How does it vary across cultures and species?
The biology
The most interesting scientific material covers the neurological and chemical events associated with kissing. The lips contain a disproportionately large number of sensory nerve endings relative to their size. Kissing activates neural systems associated with reward, attachment, and stress regulation. The chemical exchange that occurs during kissing provides information about the immune profile of the other person — information that the nervous system processes without conscious awareness.
This immune information is relevant to mate selection in ways that researchers have explored through studies of major histocompatibility complex (MHC) compatibility. People tend to find partners with different MHC profiles more attractive in close-contact contexts, which appears to be adaptive: offspring of pairs with dissimilar immune profiles tend to have more diverse immune systems.
The anthropology and history
Kirshenbaum covers the cultural history of kissing: its presence in ancient texts, its variation across cultures (not all cultures kiss in the same ways or for the same reasons), and the ways its meaning has changed over time within Western culture.
The cross-cultural variation is particularly interesting. Kissing as a romantic or intimate gesture is not universal. Different cultures have different physical greeting and affection conventions, and the assumption that the Western romantic kiss is a natural universal is not supported by anthropological evidence.
The evolutionary question
Why do humans kiss? This is not a settled question. Kirshenbaum covers the main hypotheses: the connection to primate grooming behaviour, the relationship to infant feeding, the attachment and bonding functions, and the mate-selection function via chemical signalling.
It is likely that kissing serves multiple functions simultaneously and that different contexts activate different aspects of what is a complex behaviour.
Who this book is for
The Science of Kissing is accessible popular science — an entertaining and substantive account of a behaviour that most people engage in but have not thought about carefully. It is well-suited to readers who enjoy science writing that takes an apparently small or domestic subject seriously and finds genuine complexity in it.
Practical reflection prompts:
- What other everyday behaviours might be doing more work — biologically, psychologically, socially — than you have thought about?
Bibliographic details
- Author: Sheril Kirshenbaum
- Published: 2011
- Publisher: Grand Central Publishing