I never realised how much my sister had shaped who I became – until a psychotherapist helped me see the patterns

From childhood roles to adult relationships, sisters leave a lasting mark. Caroline Butterwick explores the psychology behind sibling bonds and what they reveal about us.

Words: Caroline Butterwick. Images: Shutterstock.

We both love swimming in the sea, cuddling cats, and country walks. We have in-jokes that make us both laugh uncontrollably, much to the bemusement of everyone else in the room. In some ways, now in our thirties, living several hours apart and with huge variation in everything from our lifestyles to world-views, my sister and I have grown into very different people.

But it still amazes me how much we have in common, from values and insecurities to our quirky mannerisms and the way we giggle.

If, like me, you have a sister — or sisters — you may sometimes find that you compare yourself with them too. I don’t just mean comparison in a competitive sense, but in wondering about who you are in relation to who they are, and how that dynamic might have shifted — sometimes in big ways — since childhood.

I speak with psychotherapist and coach Karin Peeters about how having a sister can shape us. ‘I have three younger sisters,’ she shares with me. ‘I’m the oldest. There’s a protectiveness that comes with it — I was always the babysitter, and I really liked that.

‘It made me feel very caring about them, but I think sometimes also it made me feel overly responsible. When I had my first management job and I had a team, I was taking on too much emotional responsibility for their well-being in a way that wasn’t helpful for anyone, because I was so used to that emotional caretaking, so to speak.’

Our relationships with those we grew up with can influence us greatly. A report from the British Psychological Society shares: ‘The intimate knowledge that siblings have of one another as well as the emotional intensity of the relationship means that siblings have the potential to significantly impact on one another’s development and well-being.’

It makes me think back to sitting in my sister’s bedroom, giggling over quizzes in pre-teen magazines, and talking about the things that mattered to us in a way that felt unique. These shared experiences — those memories of that camping holiday, or of walking to school together each morning — would have taught you about the world through each other’s lens.

Other people, like parents or other caregivers, can also influence these sister dynamics, says Peeters.

‘They may have said things like, “help your sister” or “you take your sister along with your friends, because they find it hard to make their own friends, so you take them under your wing.” Parents can set that dynamic up a lot where one needs to caretake of the other sister,’ Peeters explains.

There’s also the idea of social mirroring. This is where we, often without meaning to, mirror someone else’s behaviour. Growing up with a sister, you may well have picked up things from her — maybe that way you both pull the same face at something you don’t like, or the unique turns of phrase you both use.

It’s natural to find ourselves wondering about who we are in relation to our sister. ‘I know from my sisters, it’s sometimes hard to have somebody who’s already further ahead,’ says Peeters. ‘Somehow, there’s that sense of inadequacy, or that sense of comparing and then finding yourself lacking.’

This can be made harder when it feels like a sister gets treated “better” or is a “favourite” compared to us. ‘We can get habituated to certain dynamics,’ explains Peeters. ‘I think it’s quite common with things like one is the confident one, one is the initiator, one is the follower, or one is the active one, one is the pretty one, one is the smart one. We can kind of get divided in some ways. And it’s not always actually true.’

Whether we intend to or not, we use social comparison throughout our life, measuring ourselves against others, both favourably and negatively. It’s understandable that a sister would be a key person we’d do this with. If you’ve ever found yourself feeling like you revert to your childhood role when at family gatherings, you’re not alone.

‘It’s very common,’ reassures Peeters. Sometimes, this can feel a bit overwhelming, particularly if there are negative traits or dynamics that come up. Peeters suggests, where possible, taking breaks — even things like popping to the shop or going for a walk around the block can give you a bit of headspace.

In these moments, it can be worth reflecting on how you feel. ‘Really come back home to yourself,’ says Peeters. ‘How am I behaving? Am I being who I want to be? Am I myself, or am I getting sucked into these old, habituated patterns? And the best way to catch it is when it’s not yet too far removed. Check in with yourself regularly throughout the event. Even if you’re only visiting for a few hours, or if you’re having a whole weekend, come back to yourself.’

Echoing childhood dynamics

Sister relationships can be difficult, too. ‘When we don’t get along, we need to get the shame out of that and normalise it,’ says Peeters. ‘If that’s mutual, it’s easier, and then you can just relax into it and have a lukewarm relationship that is fine by both.

‘But if she wants more and you don’t want to give it, then it becomes a bit more tricky. It’s really about expressing your boundaries.’ Peeters emphasises that in some situations, it can help to see the behaviour as something different from the person.

‘So if you just don’t get along with your sister, either because she’s dysfunctional and makes you feel awful, or because you simply would never pick her as a friend, you can think about “this is how they behave and I would not choose this behaviour in my life, but this is who they are as a person. And so how can I have a relationship with the person and protect myself from the behaviour, and to see them separately?”’

She gives the example of two sisters where one often asks for help when she could do it herself, something that might be an echo of an old childhood dynamic. ‘You need to ask yourself how can I be with her as a human being, and when she is doing this “please rescue me” behaviour, how can I separate that?’ says Peeters. ‘It can be thinking, “I know that sometimes I find that a little bit tricky, but I love who she is”.

And then it becomes easier to spend time together, even if it’s just for Christmas or a wedding. It’s like, “I can look at the person behind the behaviour, and have a relationship with the person and not engage with the behaviour so much”.’ Our sisters can shape us greatly, but they’re not the be all and end all.

‘I think it’s nice that at some point we individuate,’ says Peeters. ‘That’s a word that Carl Jung uses, that we become our own person. ‘This is around thinking about what the role models are I’ve seen with my parents. This is for my role models of my siblings. But what is my view? What is my idea? Who do I want to be? If I’m not around my sister, how am I different? If I’m with my sister, how am I different, and how do I adapt?

‘And what do I want to keep because I like it, and what needs a bit of tweaking? How do I develop a level of awareness when I step into an automatic family pattern, or that I do this automatic mirroring, because it’s just what I’m used to and got habituated to. And when do I have enough conscious awareness to decide who I want to be?’

After speaking to Peeters, I find myself reflecting more on my own sister relationship and the ways she has shaped me — and, perhaps, that I have shaped her. I send her a message to ask how she’s doing — complete with a cat meme that I know she’ll love, because I love it too, and that’s definitely one thing we have in common.

Karin Peeters is a coach and psychotherapist specialising in increasing self-confidence in relationships. vitaliscoaching.com