The term Coolidge effect describes a phenomenon—seen in nearly every mammalian species in which it has been tested. In short, mates tire of intercourse with their present partner and get excited at the prospect of a new sexual partner. And, it has been seen in both male and female species.

Why? Because it’s a biological mechanism. The amount of dopamine declines with a familiar mate, but shoots up with a new mate. This increases the odds of genetic diversity in offspring.

Pair-bonding species (like humans) have biological mechanisms that allow them to find sustained relationships rewarding. But these are in tension with the more ancient Coolidge effect.

How we choose to manage our sexual desire can affect our perception of how rewarding a familiar partner is (as compared with a novel one). We can mute the Coolidge effect by engaging in daily bonding behaviours and side-stepping post-orgasmic neurochemical shifts with Synergy.

Dr. Heike Melzer discusses the Coolidge effect in this TEDx talk. Click “CC” to turn on subtitles.

Also see Post-climax effects – Dopamine.


Humans

Hormones and the Coolidge effect

(Eventual) Stability and Change Across Partnerships

The other man: Knowledge of sexual rivals and changes in sexual behavior

Genomic evidence for MHC disassortative mating in humans

A Descriptive Analysis of Sexual Problems in Long-Term Heterosexual Relationships

Men Ejaculate Larger Volumes of Semen, More Motile Sperm, and More Quickly when Exposed to Images of Novel Women

Role of Partner Novelty in Sexual Functioning: A Review

Can habituation of sexual responses be elicited in men and women when attention is maintained?

Habituation of sexual responses in men and women: a test of the preparation hypothesis of women’s genital responses

Focusing “Hot” or Focusing “Cool”: Attentional Mechanisms in Sexual Arousal in Men and Women

Habituation of Male Sexual Arousal Effects of Attentional Focus (2001)

Changes in the Magnitude of the Eyeblink Startle Response During Habituation of Sexual Arousal

Allocation of Attentional Resources During Habituation and Dishabituation of Male Sexual Arousal

Changes in erectile response to repeated audiovisual sexual stimulation

Habituation of female sexual arousal to slides and film

Habituation and Dishabituation of Male Sexual Arousal

The Long Term Habituation of Sexual Arousal in The Human Male

Habituation and Dishabituation of Female Sexual Arousal

Repeated exposure to sexually explicit stimuli: novelty, sex, and sexual attitudes

The Habituation of Sexual Arousal

Experimental Evidence for Sex Differences in Sexual Variety Preferences: Support for the Coolidge Effect in Humans

Animals

Nucleus accumbens dopamine increases sexual motivation in sexually satiated male rats

Potency in Male Rhesus Monkeys: Effects of Continuously Receptive Females

How Burying Beetles Spread their Seed: The Coolidge Effect in Real Life

Dopaminergic Circuitry Underlying Mating Drive

An unknown male increases sexual incentive motivation and partner preference: Further evidence for the Coolidge effect in female rats

Reduced proceptivity and sex-motivated behaviors in the female rat after repeated copulation in paced and non-paced mating: Effect of changing the male

Copulation and ejaculation in male rats under sexual satiety and the Coolidge effect

Effect on Ejaculatory Performance and Semen Parameters of Sexually-Satiated Male Goats (Capra Hircus) After Changing The Stimulus Female

Female Novelty and the Courtship Behavior of Male Guinea Pigs

Dynamic Changes in Nucleus Accumbens Dopamine Efflux During the Coolidge Effect in Male Rats

Effect of Novel And Familiar Mating Partners on The Duration of Sexual Receptivity in The Female Hamster