When Elon Musk was a child, his adenoids were taken out. Doctors suspected he was deaf because he spent so much time day-dreaming and staring into space.

Yet the operation made no difference to the young Musk’s behaviour. He continued to spend hours alone gazing into the distance and not responding to his name being called out. According to his biographer, Ashlee Vance, his mother concluded that Musk was not suffering from hearing loss at all but instead was living and thinking “in another world.”