Some risky behaviours, like sexting, seem hard to explain. But looking at the way groups affect us is a useful way to understand these behaviours.

Each group that we feel part of gives us a social identity. We all have a strong instinct to listen to the voices of other people in the groups which are important to us.

If the people in our groups are telling us that sexting is normal it becomes very hard to go against them, because that means questioning our very identity.

We need to question whether the groups we belong to are good – that is, do they give us social identities which make us feel valued and help us to be someone we like?

Being part of a lot of groups is useful because it means that we are not dependent on any single group to provide us with a sense of identity.

Sometimes it’s hard to leave a group which we know is not good. But looking for allies, getting pre-set phrases ready, and thinking about celery can all help.