It’s the morning after, and you’re telling your partner about that time in high school you spewed after having too many Mike’s Hard Lemonades. Sure, that’s not the sexiest conversation to have in a post-coital moment, but the hookup overshare is a real and common thing. According to new research, it’s also biologically inevitable: Even just the thought of sex causes a heightened desire to spill your guts.
In a study recently published in the Personality and Social Psychology Bulletin, a team of researchers from Israel’s Interdisciplinary Center Herzliya examined how willing people were to self-disclose after engaging with sexual stimuli. Through their work, they found an undeniable link between the two behaviors.
“Merely thinking about sex, even without being aware of it, encourages self-disclosure,” lead author and psychology professor Gurit Birnbaum tells Inverse by email.
In other words, we share our personal secrets after sex because we just can’t help it.
Through a series of experiments, she and her team found a consistent link between exposure to sex and subsequently sharing personal information. They explain this link by arguing that having sex kickstarts both a psychological and physiological need for attachment. Birnbaum argues that you don’t overshare after sex because you’re just killing time; you overshare because your brain wants you to foster a relationship.
She says this subconscious result happens whether or not someone is in a relationship or is just looking for a fling.
“Heightened self-disclosure tendencies in a sexually arousing context do not necessarily reflect the desire for a long-term relationship with a prospective partner,” she says. “Sexual arousal may trigger both short-term and long-term goals.”
Birnbaum came to this conclusion after she and her team recruited heterosexual men and women, whose ages ranged from 20 to 30, to participate in three trials.
In the first study, participants were subliminally exposed to a sexual or neutral stimuli — either an “erotic” but not pornographic photo or images of fish — then were asked to instant message with another participant about a personal event. The second study upped the ante: Participants either watched a video about the physiology of cats or Original Sin, the 2001 film with an explicitly erotic sex scene between Angelina Jolie and Antonio Banderas. After watching those videos, participants met with another participant in person and were asked to share an embarrassing moment. In the third study, participants watched either a video of people making out or one in which they were just talking, then were asked to share an embarrassing moment with another participant over instant message. Afterward, they were asked whether they would actually want to go on a date with that person.
Each study and every participant showed a consistent link between seeing a sexual image and then feeling a greater ease and desire of sharing a personal event. To cap it off, every participant in the third study who saw sexual stimuli also expressed a desire to take their instant message buddy out for a date.
Previous studies have documented that this link between the physical act of sex and the emotional experience of bonding happens because of the release of certain neuropeptides, like kisspeptin, as well as the hormones oxytocin and vasopressin. Because sex serves as a catalyst for emotional building, it plays an important role in whether or not a hookup partner becomes something more serious later on.
“Sexual desire is particularly important as a relationship-promoter in the earlier stages of relationship development,” says Birnbaum. “Specifically, sexual desire is an especially strong predictor of exertions to deepen and maintain the relationship at the stages and circumstances in which the relationship is highly vulnerable or precarious, such as when the individual does not have much information about how the partner feels about the self or when the relationship is under threat.”