In the intricate tapestry of human relationships lies a profound interplay of neurochemistry and emotional bonding. At the heart of this complex dance resides dopamine, the fuel behind human motivation, steering us toward pursuits from love to sustenance. Yet, amidst the allure of novelty and the ebb of dopamine, there exists an evolved capacity within the human brain—forging connections, nurturing intimacy, and transcending mere biochemical impulses.

Dopamine, the brain and novelty

Dopamine is at the heart of all human motivation, including sexual motivation. Without dopamine, we would have no reason to pursue partners, have sex, or even eat. Novelty stimulates dopamine production. After repetitive exposure to even the most delightful meal, gorgeous scenery or breathtaking art, our dopamine eventually drops and so does our enthusiasm for the object of our delight.

Many have argued that the same holds true for human reproduction.

The Coolidge Effect

The Coolidge Effect refers to the observed phenomenon in male animals, including humans, where they exhibit renewed sexual interest and arousal when introduced to new or novel sexual partners, despite having previously shown reduced interest or exhaustion with a current or familiar mate. This effect highlights the role of novelty in stimulating male sexual behavior, suggesting that males often display increased sexual motivation and vigor when presented with new potential mates, distinct from their established partners.

This argument is often used as a justification for infidelity. Here’s how the argument goes: “Our neurotransmitters drive us to have sex with multiple partners, because we biochemically get “bored” with the person we’re accustomed to.

And while it may be true that dopamine is highest with the “thrill of new love,” it underrates our brain’s capacity to generate novelty and its primary sex organ: the brain.

The moment when we were able to first evolve to have sex face-to-face, we are also capable of abstract language. We could not only talk about the present, but also the past and even fantasize about the future. Our bonds create the capacity to learn about our partner very well. This also means that when the dopamine drops, and men become better able to control their ejaculation, we shift from sheer reproductive mammals to creative humans.

The human condition

Humans are among the tiny minority of mammals ( 3-5%) that are pair-bonders.  Human offspring take an unusually long time to mature, so we are also wired to raise children together and to derive satisfaction and contentment in doing so.

Attachment cues are behaviors that promote emotional attachment and hold our selfishness at bay. These bonding behaviors can be understood as a process template by which humans learn love from their parents, and pass these lessons on to their children.

Eye contact, soothing vocal sounds, light, and affectionate touch, are a few examples of these intimate signals.

Because we humans inhabit a rare subset of mammals that pair bond, these parent-child attachment cues have come to serve another, more adaptive purpose. We call this secondary purpose an exaptation. Exaptation is when one adaptation, for example bird feathers to keep the bird warm, became adapted for flight.

These learned attachment cues are one of the important ways that we are able to stay in love  and for family attachment to gel. This strategy promotes family bonds, protects our children and assures their safety, security, and healthy development.

Families and social bonds are the essential building blocks of civilizations, and as old as the neocortex itself. 

We all know about the “honeymoon period” of a new committed relationship. This novel, dopamine-heightening period, lasting about 18 month to 24 months typically, are our vestibular remnants of a time when brain chemicals alone kept earlier mammals together long enough to mate.

As the neuocortex developed, so did the neurochemistry which allowed for pair-bonding and attachment. Bonding behaviors exist to sustain bonds. They promote relaxation.. not excitation.

The exaptation of pair-bonding behaviors doesn’t look the same as between an infant and a parent. But human attachment is learned in the family of origin, and these lessons play out in later adulthood.  The similarities are compelling.

Attachment cues between intimate partners

Here are a few examples of attachment cures between humans and, in some cases, other mammals:

  • Synchrony of breath and breathing
  • Wordless vocalizations which indicate pleasure or contentment.
  • Eye contact with a welcoming smile
  • Gazing into each other’s eyes.
  • Massaging with intent to comfort, especially the shoulders, head, and feet.
  • Comforting by stroking or hugging.
  • Holding each other in a close embrace.
  • Spooning.
  • Cradling your partner’s head or upper body.
  • Skin-to-skin tactile contact and playfulness.
  • Sucking and fondling of breasts.
  • Kissing with lip and tongue play.
  • Gentle and slow sexual intercourse.
  • Preparing a meal to share together.
  • Attending to your partner’s needs without being asked, or out of a sense of manipulation or quid pro quo.
  • Providing that rarest of human capacities.. undivided attention. With smiles, non-sexual touch, compliments, active listening, etc. Focused human attention is the essence of bonding behavior.

The neurochemical consequence of bonding behaviors

The frequency of bonding behavior, more so than the duration, is primary. Developing a working understanding of how exactly how we attempt to attach, as intimate partners, is the essence of science-based couples therapy.

Bonding behaviors are what Gottman refers to as “deposits” in the emotional bank account.  For the greatest impact, they need to occur on a daily basis. We now know that there is complex neurochemistry underneath human bonding behaviors. They don’t necessarily require an intense effort, but they must be done with a pure heart.

There’s ample evidence that the more you employ and enjoy bonding behaviors, the more sensitive your brain becomes to the neurochemicals (such as oxytocin) that help you to feel loving and intimately connected. (In contrast, intense dopamine stimulation promotes increasing levels of tolerance. Oxytocin promotes increasing levels of sensitivity, bonding, and connection, while dopamine requires greater and more intense “hits” to get the same level of impact. These, of course, are simplified explanations of complex and the multiple jobs of these neurotransmitters, but you get my point.


In the quest for understanding human connections, it becomes apparent that beyond the transient rush of dopamine lies a deeper realm of emotional neurochemistry. The daily deposits of bonding behaviors, the nuances of attachment cues, and the intricate dance of oxytocin guide us toward a richer, more profound understanding of intimacy and enduring love. As we navigate this terrain, nurturing and cherishing these neurochemical pathways pave the way for sustained connection and the profound richness of human relationships.