The Science of Love and Betrayal

1. Falling in love is a universal human experience with biological roots

Everyone appreciates that when we fall in love our attention seems to become focused on one person to the exclusion of all others.

Biological phenomenon: Falling in love is not a social construction, but a deeply ingrained biological process that occurs across cultures and throughout human history. This intense focus on one individual is characterized by heightened happiness, glazed eyes, and a dreamy expression.

Evolutionary advantage: The experience of falling in love serves an important evolutionary function by encouraging pair bonding and reproduction. It creates a strong emotional attachment that motivates individuals to stay together and invest in offspring. This phenomenon is observed in various cultures, from ancient poetry to modern-day research, demonstrating its universality.

Neurological basis: The brain's response to romantic love involves activation of reward centers and deactivation of areas associated with negative emotions and rational thought. This neurological pattern explains the intense, sometimes irrational nature of romantic love and its ability to override logical decision-making.

2. Neurochemicals like oxytocin and endorphins play crucial roles in bonding

Laughter seems to produce a more generalised effect that applies rather more equally to everyone who happens to be in the conversation at the time, whereas physical contact is very much a one-on-one thing.

Chemical bonding: Various neurochemicals contribute to the formation and maintenance of social bonds:

• Oxytocin: Often called the "cuddle hormone," it promotes trust and bonding
• Vasopressin: Particularly important in male bonding behaviors
• Dopamine: Associated with pleasure and reward, creating a "high" when seeing a loved one
• Endorphins: Released during physical touch and activities like laughter, creating a sense of wellbeing

Social laughter: Laughter plays a crucial role in social bonding by triggering endorphin release. This effect extends to multiple individuals simultaneously, making it an efficient way to strengthen group bonds. Research shows that even symbolic representations of laughter (like "LOL" in text messages) can increase happiness ratings in interactions.

Physical touch: While less generalized than laughter, physical touch is a powerful trigger for oxytocin and endorphin release. This explains why activities like grooming, petting, and cuddling are important in both human and animal social bonds. The intimacy of touch makes it particularly effective in strengthening one-on-one relationships.

3. Facial cues and body language are key in mate selection and attraction

Men and women show striking consistency in their preference for masculine faces in men and feminine faces in women, and this preference crosses cultural and racial boundaries.

Facial features: Humans have evolved to be highly attuned to facial cues that signal genetic quality and fertility:

• Masculine features in men (e.g., strong jaw, prominent brow) indicate high testosterone levels
• Feminine features in women (e.g., full lips, large eyes) signal youth and fertility
• Facial symmetry is universally attractive, indicating good genes and health

Body language: Non-verbal cues play a significant role in attraction and courtship:

• Women tend to use more subtle cues like hair flipping and coy glances
• Men often display more overt behaviors like chest puffing and standing tall
• Both sexes may mirror each other's body language when attracted

Scent and pheromones: While less obvious than visual cues, scent plays a role in human attraction. Studies show that women can detect subtle changes in male body odor throughout their menstrual cycle, and men find women's scent most attractive during ovulation.

4. Humans have evolved complex strategies for mate choice and relationship maintenance

Women are typically more choosy in their intimate relationships and that, as we saw in Chapter 7, they feel emotional rejection more deeply than men do would seem to provide further evidence that human pairbonds are more female-biased.

Female choosiness: Women tend to be more selective in mate choice due to their higher biological investment in reproduction. This selectivity is reflected in:

• Preference for partners with resources and status
• Greater emotional investment in relationships
• Higher sensitivity to rejection and relationship threats

Male strategies: Men have evolved different mating strategies:

• Some pursue short-term mating with multiple partners
• Others invest in long-term relationships and parental care
• Many adopt a mixed strategy depending on circumstances

Relationship maintenance: Both sexes employ various tactics to maintain relationships:

• Regular communication and shared activities
• Displays of commitment and loyalty
• Jealousy and mate-guarding behaviors
• Compromise and conflict resolution skills

These strategies reflect the complex balance between individual reproductive interests and the benefits of long-term pair bonding in human evolution.

5. Social networks and friendships are vital for emotional wellbeing and survival

Our social world in any given place is small, and we can become isolated more easily. If we lose a close friend for some reason, the ramifications are more intrusive because we have nowhere else to retreat to, no extended family or network of friends and friends of friends on whom we can rely to fill the gap.

Social brain hypothesis: Humans have evolved large brains primarily to manage complex social relationships. This ability to maintain a wide social network provides:

• Emotional support during times of stress
• Access to resources and information
• Protection against threats and predators
• Increased chances of finding suitable mates

Dunbar's number: Research suggests humans can maintain about 150 stable social relationships, with closer circles of:

• 5 intimate friends
• 15 close friends
• 50 good friends

Health benefits: Strong social networks are associated with:

• Lower rates of depression and anxiety
• Improved cardiovascular health
• Stronger immune function
• Longer lifespan

Maintaining these relationships requires regular contact and shared experiences, highlighting the importance of social activities and communication in human wellbeing.

6. Pairbonds likely evolved as protection against male harassment and infanticide

It seems that when women are most likely to conceive, they shift their preference to men with cues of good genes, but at other times they prefer men with more feminised features because this reflects a more nurturing type.

Hired gun hypothesis: Pairbonds in humans likely evolved primarily as a female strategy to gain protection from:

• Sexual harassment by multiple males
• Infanticide by rival males

Female preferences: Women's mate preferences shift throughout their menstrual cycle:

• During ovulation, they prefer more masculine men (good genes)
• At other times, they prefer more feminine, nurturing men (good fathers)

Male investment: This arrangement encouraged men to invest in:

• Protecting their mate and offspring
• Providing resources for child-rearing
• Developing paternal care behaviors

This evolutionary compromise balanced the need for good genes with the benefits of paternal investment, shaping human mating strategies and social structures.

7. Religious and virtual relationships share similarities with romantic attachments

It seems that this sense of ecstatic religious love can spill over terribly easily into something altogether less other-worldly – explicit sex.

Neurological similarities: Religious experiences and romantic love activate similar brain regions, including:

• Reward centers associated with pleasure and motivation
• Areas involved in social bonding and attachment
• Regions that suppress rational thought and skepticism

Idealization: Both religious and romantic relationships often involve:

• Creation of an idealized image of the beloved (deity or partner)
• Intense focus and devotion to this idealized figure
• Willingness to sacrifice for the relationship

Virtual relationships: Online interactions, whether religious or romantic, can trigger similar psychological responses:

• Activation of reward centers through digital communication
• Creation of strong emotional attachments without physical presence
• Potential for both deep fulfillment and vulnerability to exploitation

These parallels suggest that humans have a general capacity for forming intense emotional attachments, which can be directed towards various targets, including deities, romantic partners, and virtual entities.

8. Cultural and environmental factors influence mating strategies and preferences

In women, the average is five foot four inches, and the most fertile women were four foot eleven inches in height. This relationship held up even after controlling for socioeconomic class and the frequency of serious illness (since this is correlated with height in women).

Cultural variations: Mating preferences and strategies vary across cultures due to:

• Economic conditions (e.g., resource scarcity vs. abundance)
• Social norms and religious beliefs
• Historical factors (e.g., colonialism, wars)

Environmental influences: Physical environment shapes mate preferences:

• In harsh environments, women may prioritize resource provision over physical attractiveness
• In regions with high pathogen prevalence, physical symmetry (indicating good genes) becomes more important

Socioeconomic factors: Social status and wealth affect mating strategies:

• In stratified societies, status often trumps physical attractiveness
• Economic inequality can lead to increased polygyny or delayed marriage

Body size preferences: Optimal body size varies across cultures and environments:

• In resource-scarce environments, larger body size may be preferred as it indicates access to resources
• In modern Western societies, slimness is often idealized, especially for women

These variations demonstrate the flexibility of human mating strategies in response to different environmental and cultural contexts.

9. Relationship breakdowns often stem from threats to social status or self-esteem

Between them, these accounted for around two-thirds of all break-ups. Insults accounted for around a quarter of all break-ups, scolding accounted for around 20 per cent, and the other two for around 15 per cent each.

Common causes: Relationship breakdowns are often triggered by:

• Insults (public or private)
• Failure to attend important events
• Spreading lies or rumors
• Scolding or criticism
• Rivalry or competition

Psychological impact: These behaviors threaten an individual's:

• Social status within the relationship and broader social circle
• Self-esteem and sense of worth
• Feeling of being valued and respected by their partner

Gender differences: Men and women tend to react differently to relationship threats:

• Women are more likely to report falling out with romantic partners
• Men are more likely to report conflicts with siblings or colleagues

Long-term consequences: Relationship breakdowns can have lasting effects on:

• Future relationship patterns and trust
• Mental health and wellbeing
• Social support networks

Understanding these patterns can help individuals and couples navigate conflicts more effectively and maintain healthier relationships.

Last updated: May 22, 2025