Introduction
Sheril Kirshenbaum's "The Science of Kissing" takes readers on a fascinating journey through the world of smooching, exploring its biological, psychological, and cultural significance. This book delves into the often-overlooked realm of kiss research, uncovering surprising facts and shedding light on why this seemingly simple act plays such a crucial role in human relationships and society at large.
From the earliest moments of our lives to the complex mating rituals of adulthood, kissing shapes our experiences and connections with others in profound ways. Kirshenbaum's work brings together insights from various scientific disciplines, offering a comprehensive look at the multifaceted nature of kissing and its impact on our lives.
The Early Roots of Kissing
One of the most intriguing aspects of kissing is how deeply rooted it is in our early experiences. As infants, we begin to associate lip contact with comfort, security, and love through the act of nursing. This connection forms the foundation for our later experiences with kissing and intimacy.
The book explains that babies are naturally inclined to use their lips, even before birth. They suck their thumbs in the womb and instinctively purse their lips for nursing as soon as they're born. This innate behavior highlights the importance of lip stimulation in human development.
Nursing provides more than just nourishment for babies; it creates a safe and calming environment that fosters positive associations with lip contact. This early imprinting plays a crucial role in shaping our future relationships and attitudes towards physical intimacy.
Kirshenbaum also explores the historical practice of premastication, or mouth-to-mouth feeding, which was common for thousands of years before the invention of mechanically mashed baby food. This practice not only served a practical purpose but also strengthened the emotional bond between parent and child, further reinforcing the positive associations with mouth-to-mouth contact.
The author notes that premastication isn't limited to humans; it's observed in other animals like apes and birds as well. This widespread occurrence across species suggests that the behavior has deep evolutionary roots and serves important biological and social functions.
The Social Significance of Kissing
Kissing isn't just about romance and intimacy; it has played various roles in human society throughout history. Kirshenbaum takes readers on a journey through time, exploring how kissing has been used to seal contracts, mark social status, and even greet important figures.
One fascinating tidbit the book reveals is the origin of using "X" to represent a kiss. This practice dates back to the Middle Ages when contracts were sealed with a kiss, and the spot to be kissed was marked with an "X". This historical tidbit provides a delightful connection between our modern digital communication habits and centuries-old traditions.
The book also delves into the hierarchical nature of kissing in medieval society. Where you kissed someone – whether it was their hand, robe, or even the ground – indicated your relative social status. This practice demonstrates how kissing has been used as a tool for social organization and communication beyond its romantic connotations.
Kirshenbaum extends her exploration of kissing-like behaviors to the animal kingdom, revealing that many species engage in similar actions. From ground squirrels brushing noses to cats licking each other, these behaviors serve to exchange information and strengthen relationships within animal communities. The author's inclusion of various animal examples, including the surprising fact that even porcupines engage in nuzzling, highlights the universal nature of these intimate gestures across species.
The book emphasizes that regardless of the specific method, these kiss-like behaviors in animals serve similar purposes to human kissing: signaling trust, acceptance, and willingness to enter another's personal space. This parallel between human and animal behavior underscores the fundamental importance of such intimate gestures in social bonding.
Kissing as a Compatibility Test
One of the most intriguing aspects of kissing that Kirshenbaum explores is its role as a subconscious compatibility test between potential mates. The book delves into the science behind why we're attracted to certain people's scents and how this relates to our genetic makeup.
The author explains that every human has a unique scent due to special glands in various parts of our body. When looking for a mate, we're instinctively drawn to individuals with scents different from our own. This preference isn't just a matter of personal taste; it's rooted in our biology and serves an important evolutionary purpose.
Kirshenbaum introduces readers to the concept of MHC genes, which play a crucial role in our immune system. These genes help our bodies distinguish between our own cells and foreign invaders. The more diverse our MHC genes, the stronger our immune system tends to be.
The book explains that when two parents have very different MHC genes, their offspring are likely to have an even stronger immune system. This biological fact underlies our subconscious preference for mates with different MHC genes than our own.
To illustrate this point, Kirshenbaum discusses Claus Wedekind's famous "sweaty t-shirt" study from 1995. In this experiment, women were asked to smell t-shirts worn by different men and select the ones they found most attractive. Remarkably, the women consistently chose shirts from men whose MHC genes were most different from their own, even though they had no conscious awareness of this genetic information.
This fascinating insight into the biology of attraction helps explain why kissing feels "right" with some people and "wrong" with others. It's not just about chemistry in the romantic sense, but actual biological chemistry at work.
The Physiological Effects of Kissing
Kirshenbaum's book takes readers on a journey through the body's response to kissing, revealing how this simple act can have profound effects on our physical and mental state. The author compares the rush of kissing to the high experienced by drug users, particularly those using cocaine.
When we kiss, our bodies go through a series of rapid changes. Our breathing deepens, blood vessels dilate, causing us to flush, and more oxygen is sent to our brain. This increased blood flow and oxygenation set the stage for a cascade of chemical reactions that create feelings of euphoria and excitement.
The book breaks down the key chemical messengers released during kissing:
Adrenaline: This hormone increases our energy levels and heart rate, contributing to the excitement we feel.
Serotonin: Known for its mood-boosting properties, serotonin helps us feel relaxed and content.
Dopamine: This neurotransmitter is responsible for feelings of pleasure and euphoria, and it leaves us craving more.
Kirshenbaum points out that the release of these chemicals, particularly dopamine, activates the same brain regions as cocaine use. This explains why kissing can feel addictive and why we often find ourselves longing for more after a passionate encounter.
The author also draws an interesting parallel between the serotonin levels of people who have just fallen in love and those with obsessive-compulsive disorders. This similarity in brain chemistry helps explain the obsessive thoughts and behaviors often associated with new love.
Beyond these short-term effects, Kirshenbaum explores how kissing can have long-lasting impacts on our health and relationships. The act of kissing triggers the release of oxytocin, often called the "love hormone" or "bonding hormone." Oxytocin plays a crucial role in strengthening emotional attachments, particularly between romantic partners or family members.
The book explains that while the effects of dopamine may fade over time, leading to a decrease in sexual desire, oxytocin continues to foster long-term bonding. This hormone is responsible for the deep, lasting connections that allow couples to maintain relationships for decades.
Kirshenbaum also highlights the health benefits of kissing by discussing its effect on cortisol levels. Cortisol, known as the "stress hormone," can have negative impacts on our health when chronically elevated, including increased blood pressure and a weakened immune system. Kissing helps to lower cortisol levels, potentially contributing to better overall health and well-being.
Kissing and Reproduction
Kirshenbaum's exploration of kissing wouldn't be complete without examining its role in human reproduction. The book draws parallels between modern scientific understanding and ancient wisdom, referencing the Kama Sutra's dedication of an entire chapter to kissing.
The author explains that kissing is not just a cultural practice but an evolutionary adaptation that serves to fuel our sex drive and increase the likelihood of reproduction. The sensitive nerve endings in our lips stimulate the limbic system, the part of our brain associated with love, lust, and passion.
Interestingly, Kirshenbaum points out that men and women may approach kissing with different biological imperatives. Women, according to studies cited in the book, tend to use kissing as a way to assess potential partners. The author notes that a significant majority of women wouldn't consider having sex with someone unless they had kissed them first.
Men, on the other hand, seem to have a different strategy. The book discusses studies showing that men prefer kisses with more tongue involvement. Kirshenbaum presents the theory that this preference might be related to the transfer of testosterone through saliva, which could potentially increase a woman's receptiveness to sexual activity.
These gender differences in kissing behavior highlight the complex interplay between biology, psychology, and culture in human mating rituals. While individual experiences may vary, these general trends provide insight into the evolutionary purposes behind our kissing behaviors.
The Persistence of Kissing
Despite its importance in human relationships and biology, kissing has faced numerous attempts at prohibition throughout history. Kirshenbaum's book explores various efforts to ban or restrict kissing, demonstrating the resilience of this fundamental human behavior.
The author discusses how different rulers and governments have tried to outlaw kissing, often citing health concerns. For example, during the Great Plague in London in 1665, authorities attempted to ban kissing to prevent the spread of disease. More recently, in 2008, South Africa considered a law to prohibit children under 16 from kissing, misguided attempt to curb HIV transmission.
Religious institutions have also tried to regulate kissing. The book mentions several attempts by the Catholic Church to ban kissing on moral grounds and because of its potential to lead to sexual activity. However, as Kirshenbaum points out, none of these efforts were successful in the long term.
The persistence of kissing in the face of these bans and restrictions underscores its fundamental role in human nature. As the author argues, kissing is not just a cultural practice that can be easily legislated away; it's a deeply ingrained biological and psychological need.
Final Thoughts
"The Science of Kissing" offers readers a comprehensive and engaging exploration of a seemingly simple yet profoundly important human behavior. Sheril Kirshenbaum's work brings together insights from biology, psychology, anthropology, and history to paint a rich picture of why we kiss and how it affects us.
The book's key messages can be summarized as follows:
Kissing is deeply rooted in our biology, starting from our earliest experiences as infants.
It serves multiple social purposes across human cultures and in the animal kingdom.
Kissing acts as a subconscious compatibility test, helping us choose suitable mates.
The act of kissing triggers significant physiological responses, including the release of various hormones and neurotransmitters.
Kissing plays a crucial role in human reproduction and mate selection.
Despite numerous attempts to ban or restrict it, kissing has persisted throughout human history due to its fundamental importance.
Kirshenbaum's work reminds us that there's much more to kissing than meets the eye. It's not just a pleasant sensation or a social custom, but a complex behavior that has evolved to serve important biological and social functions. By understanding the science behind kissing, we gain deeper insights into human nature, relationships, and the intricate connections between our bodies and minds.
The author's exploration of this topic invites readers to reconsider their own experiences with kissing and to appreciate the depth and complexity behind this seemingly simple act. Whether it's the rush of a first kiss, the comfort of a familiar partner, or the social bonding of a greeting, kissing shapes our lives and relationships in profound ways.
As we navigate the complexities of human relationships in the modern world, Kirshenbaum's work serves as a reminder of the power and importance of physical connection. In an age of digital communication and social distancing, understanding the biological and psychological significance of kissing underscores the irreplaceable value of human touch and intimacy.
"The Science of Kissing" not only satisfies our curiosity about this universal human behavior but also provides valuable insights that can enhance our understanding of ourselves and our relationships with others. It's a testament to the fact that even the most common aspects of human behavior can reveal fascinating truths about our nature when examined through the lens of science.