The psychology of secrets

We all have our secrets. In fact, you probably have about 13, five of which you've never told anybody else. Yet despite being such a common experience, until recently, secrecy received relatively little research attention. Now, though, its secrets are being well and truly spilled.

Studies are revealing everything from which of our friends is most likely to betray a confidence to why one type of secret, in particular, is really worth holding onto.

How many secrets?

That estimate of how many secrets the average person has comes from seminal research, led by Michael Slepian at Columbia University, published in 2017. The study involved asking thousands of people about their secrets, which – as one might imagine for such a topic – brought to light an array of interesting findings.

Firstly, almost all of us harbour secrets; around 97 per cent of the participants admitted to keeping something hush. Secondly, of the 38 main types of secrets that the team identified, the most common were: romantic thoughts about someone who was not the participant's partner, secrets about their sexual behaviour, and emotional infidelities.

This paper was also pivotal in re-characterising secrets not just as information that we actively try to conceal in social situations, but as information that we have and don't want to be shared. The team found that the various study groups – which included tourists canvassed in New York, as well as online participants – reported privately brooding about a secret twice as often as they actively stopped themselves from blurting it out to someone else. They also found that this brooding was the most psychologically harmful aspect of having a secret.

Shame versus guilt

In 2019, Slepian and colleagues reported in Emotion that we brood more about secrets that we feel are shameful than we do over secrets that we consider to be 'guilty'. In this study, the types of secrets that evoked the most shame concerned the participants' mental health, a prior traumatic experience, or unhappiness with their physical experience. Guilty secrets, on the other hand, were often about hurting, lying to, or violating the trust of someone else.

Differences were also present in the experiences associated with carrying each type of secret. When participants were ashamed of a secret, the team found that this led to feelings of worthlessness and powerlessness, while guilty secrets were associated more with feelings of remorse or regret about the action. Guilty secrets were, then, less psychologically damaging, as they were more likely to make people feel they had 'done a bad thing', not that they were a 'bad person'.

Risks versus benefits

Whether a secret feels shameful or guilty, it can weigh on us. Confessing these kinds of secrets should alleviate some of this burden – but opening up could also make a confidante think much worse of us. The potentially good news from a 2024 study in the Journal of Personality and Social Psychology is that we generally over-estimate how harshly we'll be judged.

Michael Kardas at Oklahoma State University and colleagues first asked participants to imagine revealing a negative secret (the secrets ranged from admitting an inability to ride a bike to confessing infidelity) and to predict how another person would judge them. The imagined confidante varied between experiments, so that sometimes it was a stranger, sometimes a friend, and other times the participant's romantic partner.

In the next stage of the study, the participants actually revealed their secrets to these people, and Kardas and colleagues explored the repercussions. They found a consistent mismatch, even for more serious secrets – time and again, the participants expected to be judged more harshly by their confidantes, expecting to get lower ratings for honesty and trustworthiness than they actually received. This doesn't mean that confessing a dark personal secret carries no reputational risks, of course, but this work does suggest that the cost to our reputation may at least be less than we fear.

Other work has found, though, that there's one type of secret in particular that we tend keep to ourselves not because we fear harsh judgements, but because sharing it could stop us from achieving our goals. This is knowledge that we are sick with an infectious disease. 

This research, led by Wilson N. Merrell and published in 2024, found that about three-quarters of the US-based participants confessed to concealing illness in a social situation, often because they wanted to go to a party, or because they wanted to go to work to complete a goal. 'Disease concealment' seems to be a common behaviour, the team notes, with important public health implications, especially as the Covid-19 pandemic continues.

Research also shows that there's one type of secret that it's actually best not to share – at least in the short term. This is a 'good news' secret – getting good news about your health, perhaps, or finally achieving a goal. This finding comes from a 2024 study, again involving Michael Slepian, which revealed that thinking about secret good news made people feel energised, particularly when they were staying mum because they were planning to surprise someone with it.

Who to confide in?

Sharing secrets can also bring benefits that go beyond the psychological impact of unburdening ourselves. Opening up can tighten bonds between acquaintances or friends, even for young children. In fact, a 2020 study led by Zoe Liberman at the University of California Santa Barbara shows that from about the age of six, we understand that when a friend confesses a secret, if we want to maintain their trust and further cement that relationship, we really should try to keep it to ourselves. 

A 2018 study by Katie Greenaway at the University of Melbourne and Michael Slepian found that, at any one time, we hold about 17 secrets from other people. But just because friends can hold secrets, that doesn't necessarily mean that your secrets are always safe when shared with a carefully chosen few. Far from it.

In 2022, Jessica Salerno at Arizona State University and Michael Slepian reported findings from nine studies that investigated when and why people divulge another person's secrets. They found that about a third of secrets about other people were passed on. 

This body of secrets included second-hand secrets (people sharing secrets that had been shared with them), but when the team homed in on only secrets that had been confessed directly to the participants, more than a quarter were still passed on. 'This means that a majority were kept, but a meaningful percentage, that some might consider horrifying when they consider their own confided secrets, were revealed to at least one other person,' commented Salerno in a statement at the time.

Other researchers have suggested that someone else's secret can feel like a form of social currency – so people who are more concerned about improving their social standing would be more prone to cash these secrets in. But this 2022 work also revealed another insight into why some friends may be more likely to be blabbermouths than others. 

Salerno and Slepian consistently found that participants were more likely to pass on another person's secret action or thought when they deemed it to be morally wrong. When the researchers investigated this further, they found that this was because it satisfied an emotional need to see that person punished. There was yet another twist, though: if the morally outraged confidante believed that the person revealing the secret had already been punished, they were less inclined to divulge it.

So if you are thinking of sharing a secret with a friend, try to pick one who's less likely to find it immoral – or, if you have been punished in some way for it, make sure you spell that out. That way, you should gain the psychological benefits of a confession while minimising the risks of your secret being spread – and perhaps also encouraging your confidante to judge you less harshly.