World leaders are often accused of hubris, of wielding power in arrogant and self-serving ways.

Leaders and managers in public life rarely escape criticism when they make unpopular decisions either. 'The power has gone to his head' is an oft-heard accusation.

So are leaders losing touch with reality when they act in a power-hungry way?

According to psychologist Guy Claxton, professor of learning sciences at the University of Winchester, their actions could be to do with "a disorder of intelligence".