Paul Valéry, a French poet and philosopher once wrote: “Men are distinguished by what they show, and resemble each other by what they hide.” When it comes to secrets, their broad contents are no longer secret. Researchers, therapists, and professionals working on the field discovered that most of us share the broad outlines of what we keep as secrets.

Professor Michael Slepian and his colleagues from Columbia Business School’s Management Division conducted a series of experiments in 2017 to discover the categories of secrets that people generally keep.

They found 38 categories of secrets that represent the most commonly kept types of secrets. Those types of secrets include: Sexual infidelities, emotional infidelities (like flirting), lies, financial difficulties, drug use, violation of trust, theft, hidden relationships, discontent at work, self-harm, mental health problems, secret hobbies, and others (see below for full list).

Let’s dive in more to discover all those secrets and how common are they.

Slepian’s 38 categories of secrets

In the paper which was published in the Journal of Personality and Social Psychology, Slepian and his colleagues, Jinseok Chun and Malia Mason, have collected through multiple studies about 13,000 secrets from 2,000 participants that they have divided into 38 categories. So, what are those types of secrets that the researchers found?

The full list of secrets’ categories

Click to show the full list of secrets’ categories.
  1. Lies
  2. Sexual infidelities
  3. Emotional infidelities (e.g., flirting)
  4. Extra-relational thoughts (Thoughts about having a relationship with another person, while already in a relationship)
  5. Sexual orientation (concealed your sexual orientation/gender identity)
  6. Sexual behavior (other than sexual orientation. e.g., porn, masturbation, fantasies, unusual sexual behavior)
  7. No sex (Keeping secret a lack of having sex)
  8. Drug use
  9. Habit/addiction (excluding drugs)
  10. Secret hobbies
  11. Theft
  12. Trauma
  13. Physical discontent (Dissatisfied with something physical about yourself)
  14. Mental health (Had mental health issues, or dissatisfied with something about yourself other than the physical appearance)
  15. Belief/ideology (political views, religious views, views about social groups, prejudice, etc.)
  16. Work cheating (did something improper at work/school)
  17. Work discontent (Dissatisfied with your situation at work)
  18. Poor work performance
  19. Finances (e.g., huge debts, amount of money you have)
  20. Family detail (kept a detail about your family secret)
  21. Other-harm (emotionally or physically hurt someone and kept it a secret from someone else)
  22. Self-harm (physically harming oneself)
  23. Illegal (other than drugs or stealing)
  24. Pregnant (being pregnant and not telling some people)
  25. Abortion (had an abortion)
  26. Violate trust (e.g., by snooping, revealing information about someone, breaking or losing something that belongs to someone without telling them, etc.)
  27. Romantic desire (while single. e.g., a crush, or being secretly in love with someone)
  28. Romantic discontent
  29. Hidden relationship (hiding a current relationship, or keeping a past one a secret)
  30. Other woman/man (another person was cheating on their partner — with you)
  31. Social discontent (Dislike a friend, or unhappy with a current social life)
  32. Marriage proposal (Planning to propose marriage)
  33. Surprise (Planning a surprise for someone, other than marriage proposal)
  34. Preference (Kept secret a preference for something)
  35. Employment (Kept secret a job or employment that you have)
  36. Ambition (Kept a secret ambition, secret plan, or secret goal for yourself)
  37. Counternormative (abnormal behavior, unrelated to any of the above categories. e.g., tying your shoes three times in the morning)
  38. Personal story (A specific story you keep secret, unrelated to any of the other categories)

This analysis represents the most complete classification of secrets to date (as in 2020).

You can also take the Common Secrets Questionnaire developed by the team of researchers here.

How did the researchers come up with this list?

First, the research team asked 1,000 participants to describe a secret they were keeping. The responses were then reviewed and a first list of categories was compiled.

This initial list was refined to best capture the data, and categories were selected that were not overly narrow nor too broad.

For example, rather than distinguishing between specific types of theft, such as shoplifting or stealing a wallet, the researchers labeled all the similar cases as “theft.” Additionally, when a category was as frequent as a broader category it could fall in, they correspondingly gave it its own category.

However, they noted that participants’ experiences were sometimes very diverse and included some small offenses (e.g., receiving too much change at the counter) as well as some serious ones (abuse, fraud, etc.). Therefore, they would add another category to reflect these differences.

In addition, there were cases where categories had to be added to reflect participants’ responses better. For example, drug use could fall into the category of “illegal,” but for participants, it was the substance itself that seemed significant, so the researchers classified it into a category called “drug use.”

After compiling all 38 categories, and since this list was derived using a data-driven approach, the researchers had to confirm its validity outside the initial sample. Therefore, a second set of 1,000 responses from participants was examined, and it was shown that the categories were consistent with the data.

The most common secrets people keep

In summary, the series of studies conducted by Slepian and his colleagues showed that participants had in their lives about 20 of the 38 categories of secrets, of which 13 are currently secret, 4 were disclosed immediately, and 3 were once secret but are no longer so.

In each study, the most common secrets that people keep entirely to themselves are:

  • Extra-relational thoughts (wanting someone other than their partner)
  • Emotional infidelity (e.g., flirting with someone other than their partner)
  • Theft
  • Hidden personal life events
  • Betrayal
  • Life ambitions
  • Unusual sexual behavior
  • Sexual infidelity

Whereas abortion, sexual orientation, marriage proposals, drug use, work discontent, and surprises for others are rarely kept entirely to oneself.

The following chart shows the percentage of participants that experienced any type of self-concealment (hiding information). The bars are divided into four parts:

  1. Secret for all people I know: The percentage of participants that keeps it entirely to themselves.
  2. Secret for some people I know: The percentage of participants that shared a secret with a few others.
  3. Past secret: The percentage of participants that kept the secret but not anymore.
  4. Never a secret: The percentage of participants who immediately disclosed the secret.
chart showing frequency of secrets held by people
Breakdown of how frequent each category of secrets is

download the full size chart here.

Good and bad secrets

Although the list of themes compiled by Slepian and his colleagues is universal and represents the most common types of secrets that people keep, we will turn here to a more general classification of secrets.

In her book Secrets in Families and Family Therapy published in 1993, Evan Imber-Black, a leading American figure in family therapy identifies four types of secrets.

Soft and essential secrets

First, there are good secrets that contribute to our well-being and shape our sense of identity. These are the “soft secrets,” they are light and often fun. For example:

  • Secretly planning a surprise birthday party
  • A secret marriage proposal plan
  • The gender of an unborn child

There are also the “essential secrets” that refer to our vulnerability, our complexes, and our difficulties. As an example:

  • The thoughts we keep in our personal diary
  • The intimate moments we share with our partners
  • The fun secrets we share between close friends

Toxic and dangerous secrets

Then there are the bad secrets, which seriously endanger their holders as well as those who are excluded from them.

These are “toxic secrets” forming what are classically called family secrets, as an example:

  • The suicide of an aunt disguised as an accident
  • Hiding from someone that he’s adopted
  • The troubled past of a close friend

And “dangerous secrets” concerning actions that immediately threaten the physical and moral integrity of a person:

  • An HIV-positive man who does not inform his partner
  • A husband who beats his wife
  • An uncle who makes sexual advances

All these types of secrets are very different in terms of why we keep them. For example, there are facts of which we are ashamed, some of which we feel guilty, and others which we hide to preserve our image in the eyes of others. There are also those we conceal because we believe we are doing the right thing to protect our loved ones. Read more here about why do people keep secrets


Jim Miller

Jim spent his twenties trying tounderstand how our primitive minds get in the way of self-growth. He has a lot of interesting ideas about human psychology that he doesn't hesitate to share when opportunity presents itself.


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Related Articles


Jim Miller

Jim spent his twenties trying tounderstand how our primitive minds get in the way of self-growth. He has a lot of interesting ideas about human psychology that he doesn't hesitate to share when opportunity presents itself.

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Be the first to receive the latest articles and exclusive offers on our products directly in your inbox

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*You can unsubscribe any time via the link provided in Newsletter.