The Coolidge Effect: Why Novelty Is Sexy (and Long-Term Monogamy Isn’t Easy)
Saturday, July 26, 2025. I originally wrote about the Coolidge Effect for the old CTI blog nearly 10 tears ago. I think some reworked version of it is still on their site. This post is an update on the Coolidge Effect for life in 2025.
If you’ve ever wondered why people in long-term relationships sometimes feel like they’re watching the same movie on repeat—even when they love the plot and the co-star—it might help to blame an old presidential anecdote and a pile of horny lab rats.
Welcome to the Coolidge Effect: a not-so-fun biological feature that makes sexual novelty exciting… and sexual familiarity, well, less so.
This post is going to walk you through the science, the controversy, the cultural baggage, and the implications of the Coolidge Effect for real couples in real bedrooms—not just rats in cages.
And because we’re grown-ups, we’ll do this with the usual cocktail of dry humor, APA-style citations, and compassionate skepticism for the stories we tell ourselves about desire.
What Is the Coolidge Effect?
The Coolidge Effect is a phenomenon observed in animals (humans included) in which individuals—particularly males—exhibit renewed sexual interest when introduced to a novel partner, even after refusing sex with a familiar one.
It’s not a theory about affairs. It’s not a moral position. It’s a neurobiological reality that highlights how dopamine and novelty work together to keep reproduction humming along in nature’s grand experiment.
The term allegedly comes from an old joke involving President Calvin Coolidge. During a visit to a farm, Mrs. Coolidge reportedly noticed a rooster copulating frequently and remarked, “Tell that to the President.”
When Calvin was told, he asked whether the rooster copulated with the same hen each time. “No,” the farmer said. “A different one each time.” Coolidge replied, “Tell that to Mrs. Coolidge.”
As far as presidential zingers go, this one’s endured because it captured something fundamental—and measurable.
Science, Rodents, and Rotating Mates
In classic lab studies, male rats placed with a sexually receptive female will copulate enthusiastically at first, then lose interest. But if a new female is introduced—even if the first is still receptive—the male revives with vigor. This cycle can repeat again and again (Wilson, Kuehn, & Beach, 1963).
And it’s not just rats. Similar patterns have been documented in rams, monkeys, and humans. Dopamine, the neurotransmitter responsible for reward and motivation, surges with sexual novelty and declines with repetition (Fiorino & Phillips, 1999).
In studies on humans, sexual arousal declines with repeated exposure to the same stimuli but rebounds with novel stimuli—a process known as habituation and dishabituation (O’Donohue & Geer, 1992). In short: our brains seem wired to crave newness.
But Wait—What About Women?
This is where things get both interesting and politically awkward.
Most early Coolidge Effect research focused on males. Because sperm is cheap and eggs are expensive, the evolutionary story went, males evolved to seek quantity, females to seek quality. But that’s an oversimplified (and sexist) tale.
More recent research suggests women are not immune to the Coolidge Effect. In fact, they may experience even stronger desire for novelty in certain hormonal windows—particularly around ovulation (Gangestad & Thornhill, 2008). Women’s sexual responsiveness also shows more rapid habituation than men’s in some laboratory settings (Both et al., 2007).
So yes: the Coolidge Effect has equal-opportunity implications for modern relationships.
Welcome to Dopamine’s Basement
The real story here isn’t about gender. It’s about dopamine and habituation.
Your brain loves dopamine. It’s the neurochemical that says: “This is new! This is interesting! This is worth your attention!” The first time you kiss someone, dopamine floods your system. The 200th time? Not so much.
That’s not because you don’t love your partner. It’s because your brain has efficiently coded them as “known quantity.”Familiar things don’t spike dopamine. New things do.
And that’s where the Coolidge Effect becomes both a diagnosis of desire's decay and a clue about how to revive it.
Why Therapists (and Your Marriage) Should Care
I can’t count the number of couples I’ve sat with who say:
“I love them. I’m just… not attracted like I used to be.”
This is not code for “I don’t care.” It’s code for “I don’t know how to feel desire for something my brain now files under ‘routine.’”
The Coolidge Effect isn’t the only culprit in long-term relationship ruts, but it is a major contributor. It helps explain:
Why infidelity often isn’t about love, but about novelty
Why some people become addicted to the chase
Why “settling down” feels like emotional death to those who equate desire with newness
Why long-term couples may stop initiating sex even when emotional intimacy is high
The Culture of Replacement: A Modern Twist
Let’s bring in some commentary, gentle reader.
In an age of algorithmic swiping and infinite scrolling, the Coolidge Effect is no longer confined to biology. It's now limbically capitalized by dating apps, porn sites, and even social media platforms that thrive on novelty and short attention spans.
This isn’t just bad for marriage. It’s also bad for human development.
Esther Perel (2017) argues that modern desire is caught between two conflicting needs: security and adventure.
But perhaps it’s more accurate to say that modern relationships are caught between two competing dopamine economies—the enduring comfort of the known and the digital sugar rush of the new.
Can You Outwit the Coolidge Effect?
Short answer: Not entirely.
Long answer: You can’t stop dopamine from liking novelty, but you can outsmart your own habits.
Try this:
Make the familiar unfamiliar. Novelty doesn’t require new people—just new experiences. Travel. Roleplay. Take risks together. Change the script.
Don’t confuse comfort with chemistry. Many couples get too good at “doing life” and forget how to surprise each other.
Practice “erotic differentiation.” Let your partner be mysterious again. Want them from a distance. Let them evolve.
Honor desire without shaming the system. You’re not broken if you miss the excitement of newness. You’re wired that way. So is everyone else.
Do inner work. Many people use novelty to escape self-confrontation. When long-term desire fades, the question isn’t just “Why don’t I want them?” It’s also “What part of myself have I stopped bringing to this?”
The Paradox of Long-Term Desire
The very thing that makes long-term love meaningful—familiarity, safety, history—is also what makes long-term lust harder to maintain. For some, the Coolidge Effect is nature’s cruel joke. But it’s also an invitation to spiritual growth through limitation. This is what Esther misses.
Because real intimacy isn’t about getting rid of boredom. It’s about becoming the kind of person who can re-invent magic without replacing the magician.
That’s not only a biohack. For some, it’s also a deliberate practice.
And like all good practices—cooking, prayer, jazz improv, marriage—it rewards you for showing up even when the dopamine doesn’t.
Be Well, Stay Kind, and Godspeed.
REFERENCES:
Both, S., Spiering, M., Everaerd, W., & Laan, E. (2007). Sexual behavior and responsiveness to erotic stimuli following laboratory-induced sexual arousal. Archives of Sexual Behavior, 36(6), 881–890. https://doi.org/10.1007/s10508-007-9203-y
Fiorino, D. F., & Phillips, A. G. (1999). Facilitation of sexual behavior and enhanced dopamine efflux in the nucleus accumbens of male rats after D-amphetamine–induced behavioral sensitization. Journal of Neuroscience, 19(1), 456–463. https://doi.org/10.1523/JNEUROSCI.19-01-00456.1999
Gangestad, S. W., & Thornhill, R. (2008). Human oestrus. Proceedings of the Royal Society B: Biological Sciences, 275(1638), 991–1000. https://doi.org/10.1098/rspb.2007.1425
O'Donohue, W., & Geer, J. H. (1992). The habituation of sexual arousal. Addictive Behaviors, 17(5), 567–573. https://doi.org/10.1016/0306-4603(92)90070-V
Perel, E. (2017). The state of affairs: Rethinking infidelity. Harper.
Wilson, J. R., Kuehn, R. E., & Beach, F. A. (1963). Modification in the sexual behavior of male rats produced by changing the stimulus female. Journal of Comparative and Physiological Psychology, 56(3), 636–644. https://doi.org/10.1037/h0047306