By Christian Jarrett

What makes for a good life? Current psychological theory highlights the importance of relationships, belonging and having a sense of purpose. Gratitude, forgiveness, generosity and self-compassion often get a mention too. According to a team of psychologists at George Mason University, there is however a glaring omission. Sex.

“In theoretical models of well-being, sex is rarely discussed and in many seminal articles, ignored,” they write in their new paper published in Emotion.

Todd Kashdan and his colleagues have attempted to correct this oversight with a three-week diary study, in which they looked at the associations between sex frequency and quality and not only positive mood, but also sense of meaning in life. “If an individual gains sexual access to a romantic partner, this should raise momentary affect … and increase one’s sense of self-worth or meaning in life,” they predicted.

One-hundred and fifty-two college students (116 women; average age 24; 63 per cent in a monogamous romantic relationship) completed a diary each night for three weeks, in which they recorded their positive and negative moods that day, how meaningful their life felt, and any sexual activity they’d had since the last entry (this was interpreted broadly, from passionate kissing to intercourse), including how pleasurable and intimate it had been.

Previous survey research has found that people who report having more sex also report being happier, but most of this evidence is based on cross-sectional data so it’s not clear if sex really makes people happy or if being happy encourages sex. With their methodology, Kashdan and his team were able to unravel cause and effect.

They found that having sex on one day was associated with more positive mood states the following day, and also a greater feeling that life is meaningful (the converse wasn’t true – positive moods or more meaning in life one day was not associated with more sex the next). The overall pattern of findings were the same for men and women. Explaining their findings, the researchers said that “Meaning in life often arises when an individual feels their basic need for belonging is met with someone.”

In terms of the nature of the sexual experience, greater sexual pleasure, but not greater intimacy, was associated with better mood the next day. Kashdan’s team said this adds to growing evidence “… that often hedonic pleasures and motives are as important to cultivating a good life as deep, meaningful or virtuous activity.”

Whether participants were in a relationship or not didn’t make too much difference to the findings. What mattered more was whether they described their relationship as more intimate – if they did, the association between sex and next-day well-being gains was stronger. The researchers interpreted this as suggesting that “simply being in a committed relationship is insufficient to derive benefits from pleasurable activities”.

The only fly in the ointment for the well-being benefits of sex was that, specifically for participants who had only been in their current relationship for a short time, sex on one day was associated with more negative mood states the next. This could be a “regression to the mean”, the researchers suggested, because people in a new relationship are likely to show more daily reactivity – “on the day they had sex, negative affect is probably lower and the change to the next day is greater”.

The study is limited by its reliance on college students whose relationships, sex lives and life experiences are bound to be different than for middle-aged and older people. Also, while the three-week diary design has advantages over cross-sectional surveys, it still provides only a narrow snapshot of a person’s life. Nonetheless, Kashdan and his team believe their study makes an important contribution. “To understand the full scope of human flourishing, research on well-being needs to incorporate more rigorous scientific inquiries of sexual behaviour,” they said.

—Sexuality leads to boosts in mood and meaning in life with no evidence for the reverse direction: A daily diary investigation

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest