If you’ve heard about attachment styles – the ways we tend to relate to others in close relationships – you might have been told that it comes down to how our parents treated us. According to classic attachment theory, those of us lucky enough to receive plenty of warmth and support from our early caregivers develop a ‘secure’ model of relationships: we continue to trust close others to be there for us and feel comfortable depending on them. Those who don’t receive such support may develop ‘insecure’ models – becoming anxious about losing people, or averse to getting too attached.

Yet these models are not ‘set in stone’, contemporary attachment researchers say; we update them based on novel relationship experiences. That is, it’s not all about mom’s responsiveness to your needs. Other kinds of bonds matter, too.

Supporting this view, the research psychologist Keely Dugan and her colleagues analysed data on hundreds of people, provided by their parents, observers, and the participants themselves as they aged to around 30. As expected, people’s experiences with their mothers in childhood were correlated with how secure they felt in multiple kinds of relationships as adults. But the quality of other early relationships was predictive as well. For instance, having more positive experiences with friends in childhood was associated with feeling more secure in romantic relationships as an adult.

These results had me thinking about my own attachments in unexpected ways. Not just about how parental warmth might have equipped me to feel safe relying on others, but how my friends from childhood (some of whom I’m still close with) may have served as attachment figures themselves. Did learning – year after year, hangout after sleepover after band practice – to feel safe with my pals help set me on a course toward a happy marriage? I’m sure they’d love to take credit for that, and perhaps they deserve some.

My partner and I say, unjokingly, that if it weren’t for dating apps we never would have met. We’re different in many ways, with divergent backgrounds, interests, musical tastes and social-media diets. While our differences meant we needed help getting together, staying together has been easy – perhaps because we have something that researchers have deemed valuable in relationships: a ‘shared reality’.

Psychology researchers define a shared reality as the perception that you share with another person many of the same feelings, attitudes and beliefs about the world. If, for example, you and a partner discuss a horror movie you’ve watched together, and it turns out that you both found particular parts scary and other bits a little silly, you’d feel a sense of shared reality about this movie. It’s the impression that the other person is seeing what you’re seeing and that you’re processing it in a similar way. This can apply to all sorts of shared experiences.

Previous research has shown that having a shared reality is related to greater relationship satisfaction and commitment. Most recently, researchers found that romantic partners who experienced a higher sense of a shared reality tended to report a greater sense of meaning in life. They also reported feeling less uncertainty when faced with stressful life and world events.

For me, it’s reassuring to have someone whose experience of the world overlaps with mine – especially in moments when I doubt my own reading of a situation. When someone’s humour at a party doesn’t sit right with me but rouses rounds of laughter, that incongruence and self-doubt can feel uncomfortable. When my partner, unprompted, later admits he didn’t enjoy it either, we both sigh in relief and talk about why. It’s a grounding process, one that confirms, time after time, that neither of us is alone in seeing things the way we do.