Dr Garry said: ‘We realized that the effects of suggestion are wider and often more surprising than many people might otherwise think.’

Many studies have shown that deliberate suggestion can influence how people perform in tasks, which products they prefer and even how they respond to medicines – the placebo effect.

Dr Garry says the reason for this lies in our ‘response expectancies’, the ways in which we anticipate our responses in various situations.

The expectancies led to automatic responses which can lead to the outcome we were expecting all along.