It's hard to describe exactly what it is about a person that draws you to them. But one thing people often say is 'he/she just felt so familiar' or 'I felt like I'd always known him'.
The reason for that familiarity is we're hardwired to always fall in love with the same type of person, because we unconsciously seek the emotional environment we were raised in as a baby.
It's known as the imago or the familiar, explains relationship counsellor Steven Dromgool of Relate Counselling, because it's so close to us it's hard to see.
"In the first couple of years of life we're dependent and helpless so the only way we survive is by being very closely connected to the person who takes care of us. Our whole brain is wired to attune to that person. We learn how to speak their language; we pick up all sorts of ways of how to 'be' in that context. That's the baby part of the brain and by the age of two we've formed a fairly stable familial model of what love looks like.
"That 'familiar' model then becomes internalised as part of the 'glasses' through which we view the world," he continues.
When we go through adolescence that model becomes eroticised and turns outward, so you begin looking out in the community for that 'safe' or familiar person. But the baby brain is not concerned about your comfort, Dromgool warns, so if your 'familiar' was not great you will keep finding yourself in destructive relationships.
"The baby brain's only concern is to meet that need to be with that familiar person. The unconscious thinking is 'that was good enough to get me through the first two years of life'.
"So if you grew up in a home where there was a lot of arguing or upheaval your internal familiar model is going to involve a fair amount of chaos. You seek out that same emotional environment. There will be certain smells or things that happen that internally register a sense of safety - your whole skill set has been formed around dealing with that type of emotional environment."
Another example: "Say you grew up in a family where there was alcoholism. Our adult brains are not going to go 'I should go out and find an alcoholic'. But we'll meet someone and there will be something about the way their face looks or the way their breath smells when they say hi. That hits the vagus nerve which connects directly to the most primal parts of the brain and we go, 'Oh my god, there's something about this person that is just so familiar.'"
This can then trigger another neurochemical cascade where our brain produces a neurotransmitter called phenylethlamine (PEA) which alters our perception of the world and causes us to see our partner through rose-tinted glasses. So we interpret everything they do in a positive way, effectively filtering our own reality.
After the PEA wears off, which is typically around six to 18 months, we realise this person is not as amazing as we first thought. We see a whole series of problematic behaviours that repeat familiar and painful past patterns. Many of us just assume we made a mistake and try again, only for the cycle to repeat itself.
The most exciting work Dromgool does is helping people 'reset' their relationship course.
"It's when we see people in their second or third or fourth relationship say 'I saw this in my last two partners but I don't know how to change things' that you can get into some really exciting work with them. People start to realise that their 'familiar' model comes with some problems.
"That's the adult brain starting to recognise that our early romantic relationships were pretty destructive, and starting to process this. So often they'll get this sense of, 'for some reason I keep getting attracted to these types of people but it's not good for me'. They know what their pattern is and are starting to look at themselves and their partner more reflectively.
"When they start doing some work and learning some different ways of loving themselves and caring for themselves it can create a space within which they can start to accept that 'these relationships are not great for me' and start moving away from those relationships." We can thank, in part, our 'child brain' for having the ability to do this.
"The child brain develops from around age two to eight years old. It's a part of our brain that's oriented towards happiness, joy, pleasure and adventure. So that's the part that gives us the capacity to look for something different. It recognises that it was nice when you had that one teacher at school that held your hand or smelt nice when they leaned over to help you."
That part of the brain enables us to be open to new possibilities and seek different characteristics in a partner that make us feel safe. In turn we can then develop new ways of relating to our partner. We may have always 'gone along with things' before and not 'rocked the boat' whereas now we can feel more confident to try being more assertive, for example.
Over time our familiar model can be changed and grown, so learning from our past helps us move forward and build a new kind of familiar.