I can't find a reference for 'When people see themselves in the mirror, the chances of them to behave irrationally lowers significantly. That's why it's a good

I can't find a reference for 'When people see themselves in the mirror, the chances of them to behave irrationally lowers significantly. That's why it's a good practise to have a mirror behind the counter at a bar or customer service of any kind.'. It seems to be something only quoted on reddit and lifehack blogs as far as I can see.