In the Journal of Social Psychology, two US researchers just published the first serious study of a question that seems to obsess millions, and to which every celebrity, from Bill Gates to Kesha, is required to have an answer: what advice would you give your younger self? Robin Kowalski and Annie McCord asked more than 400 participants, aged over 30, and got some entertaining replies (“Don’t marry her. Do. Not. Marry. Her”). But we’re little closer to clarifying the mystery that’s always bothered me: what, precisely, do people take themselves to be doing when they ask themselves this question?

Because it rests, pretty obviously, on a paradox. You only acquired the wisdom on which your advice is based by making the mistakes you’re now advising your former self to avoid. For example, many respondents gave some version of the answer “Stop being so afraid” – of failure, of other people’s judgments, of life. Excellent advice, but you’ll never feel its force until you’ve first acted afraid and seen where that got you. Experience, as the saying goes, is a harsh teacher: it makes you sit the test first and only gives you the lesson afterwards.

Of course, if “advising your younger self” were just a happiness-boosting technique for calling to mind everything you’ve learned in life, nobody could object. But, browsing the replies to the study, what you sense, far more frequently, is the shiver of regret. People truly wish they hadn’t married so young, chosen a career to please their parents, or spent their money instead of saving it. And this only brings into focus the fact that regret, while entirely understandable, is a fundamentally self-contradictory emotion: the very fact that you’re feeling it means that you’ve grown into the kind of person who can look back critically on what you did in the past, when you were another kind of person. Which means that, judged by your present values, you’ve emerged from your life experience better than before, and ought (rationally speaking, anyhow) to be happy rather than regretful.

Or maybe I’m ignoring the obvious explanation, also hinted at in the study, which is that people find it useful to advise their younger selves as a way of advising their present selves, to bring their current behaviour more closely in line with what they’ve learned. This echoes the well-known observation that adopting a third-person perspective on your problems – thinking or writing about yourself in the third person, for instance – can encourage a calmer and less self-berating approach. But, in that case, I’d suggest we abandon all this time-travel business (the self-help equivalent of “Would you kill baby Hitler?”) and go straight to the real question: how would you advise a beloved friend?

Because the crucial issue, after all, isn’t what you might have done differently in the past, had you been someone that you couldn’t have been back then. It’s what you’d do now, if you treated yourself with half the kindness and goodwill you unhesitatingly extend to your favourite relatives or friends. For many people, I know, this can be a major challenge. But unlike changing the past, it has the enormous advantage of not being impossible.

Try this

Life-changing questions, an online tool at ClearerThinking.org, is based on research into which questions people found most powerful for shifting their perspective.

• This article was amended on 27 August 2019. The study about advising your younger self appeared in the Journal of Social Psychology, not Psychological Science as originally stated.