When Leonardo DiCaprio, who was born in 1974, made headlines this week for joking in an interview with Esquire that he “turned emotionally 35 last year,” I was reminded of the wide gulf in emotional maturity that I’ve often observed between my single friends and their potential paramours.

Obviously, saying that “all” men are emotionally immature (or, for that matter, that “all” women are more emotionally evolved than their male counterparts) is ludicrously imprecise—not to mention a reinforcement of an outdated gender binary. But emotional maturity is a funny thing; as age-gap relationships often demonstrate, the number of years a person has lived doesn’t always directly correspond to where they are in their lives, or who they find themselves attracted to. (see, again, DiCaprio, famous dater of women in their 20s). Here, a closer look at emotional maturity as a concept:

How is emotional maturity defined?

According to Psychology Today, emotionally mature people share three key characteristics: they take full responsibility for their feelings, their reactions, and their lives; they are able to have empathy for themselves and others simultaneously; and they speak up and tell the truth, even when it’s hard. That doesn’t mean that an emotionally mature person can never have an outburst—only that they’re willing to see where they’ve gone wrong and own up to it, especially when their behavior has negatively affected themselves or others. The idea has a lot in common with the way Joan Didion defined self-respect in 1961: “Character—the willingness to accept responsibility for one’s own life—is the source from which self-respect springs.”

What are some examples of emotionally immature characters from pop culture?

Hannah Horvath, the flailing early-20s aspiring writer in Girls, springs to mind, as does the rest of her deluded girl gang; Barney Stinson, the stunted lothario-slash-sex pest from How I Met Your Mother, certainly had some emotional maturing to do, even by the end of the series; and while the Carrie Bradshaw we met on the original Sex and the City wasn’t what anyone would call emotionally mature (remember when she whipped a full McDonald’s meal at the wall because she was mad at Mr. Big?), that has changed by the final episode of And Just Like That…, when Carrie has chosen herself as the steward of her own happiness.

What’s the risk of getting involved with someone who’s not as emotionally mature as you are?

According to clinical psychologist Nick Wignall, dating someone who’s emotionally immature may involve dealing with their tendencies to avoid vulnerability, trying new things, or being alone with themselves and their uncomfortable thoughts and feelings; and their need to get the last word in. While all (or most) of us may exhibit some of these attributes from time to time, their prevalence can seriously strain a relationship.

Can I build more emotional maturity?

Absolutely, though it will take some time. According to a 2011 National Institutes of Health study, emotional experience and overall emotional well-being are likely to improve with age over the course of a person’s life, though self-improvement and awareness practices like mindfulness, journaling, and boundary work can also be helpful.

What further reading should I do to understand emotional maturity?

Lindsay Gibson’s 2015 book Adult Children of Emotionally Immature Parents: How to Heal from Distant, Rejecting, or Self-Involved Parents is great if you’re looking to better understand attachment patterns, or how your pursuit of romantic relationships or friendships with people lacking in emotional maturity may relate to your upbringing.

Travis Bradberry and Jean Greaves’s Emotional Intelligence 2.0 is also a good choice for anyone wondering how emotional maturity differs from intellect, kindness, or any other attributes important to a healthy relationship.