Attachment theory is the way that scientists, such as psychologists, explain how we make relationships. The theory is that when you are a baby and young child you develop an attachment style, depending on how your main parent or carer (this is usually your mum, but not always) looks after you. You continue to develop this as you grow into a young adult, but the most important time is when you're a baby and toddler.
The different types of attachment style that you can have are:
Secure: About 6 out of 10 people have a secure attachment. This happens when there is a really good bond between the baby and the parent/carer for pretty much all of the things they needed. People with secure attachments generally find it easier to make friends, to trust people and are brave about giving things a go!
Avoidant (insecure): This happens when the baby experiences their parent/carer as being 'cold' or not paying them much attention for much of the time. People with secure attachments can often find it hard to make friends, although sometimes they can have lots of friends, but no-one they are really close to.
Ambivalent (insecure): This happens when the baby had a mixture of responses from their parent/carer, some good and some bad. These mixed messages mean that people with ambivalent attachment sometimes crave attention and approval. They may find it harder to keep friendships because they are demanding of their friends attention a lot of the time and may seem insecure.
Disorganised: This happens when the parent/carer has not been able to prevent the baby from seeing and hearing scary things too often, such as fighting, or if the parent/carer has been so scared or upset themselves they've not been able to comfort and help the baby. People with disorganised attachment can be unpredictable, which can mean making friends is hard for them. They might find it hard to plan out the best thing to do in tricky situations and so end up doing things & getting into situations that they later regret.
It's important to remember that parent/carers try their best to look after their children and love them very much in all but a very small number of cases. Having an insecure or disorganised attachment does not mean that a parent/carer does not love their child just as much as if you have a secure attachment. Many people with insecure and disorganised attachments live happy and successful lives.