What makes people afraid of the dark?

Loss of vision. Sight is our strongest sense and some of our natural predators, such as the big cats, had better night vision than our ancestors did. Our ancestors also had to watch out for enemy raids; even today, we may justifiably fear being burgled.

But our greatest fears come from our own minds. Many children, and some adults, are terrified of the monster under the bed. This is called the ‘sense of presence’ and is often associated with sleep paralysis, when you wake up unable to move. These monsters are due to unusual activity in areas of the brain. Then there are all those ideas that we don’t like to face – our shame, guilt, anger, anxiety or whatever it may be. These seems far worse in the dark because our brains are deprived of the visual input that keeps them busy and suppresses those unwanted thoughts.

WHY DO WE LAUGH WHEN TICKELED

Tickling  affects  the  same  unmyelinated  nerve  fibre  that  carries  pain  signals,  and  our  most  ticklish  parts  are  vulnerable  spots,  such  as  our  neck,  abdomen  and  armpits.  Laughing  for  joy  amusement  and  tickling  all  activate  brain  areas  controlling  facial  and  vocal  reactions,  but  only  tickling  activates  the  hypothalamus,  which  is  an  area  that  anticipates  pain.  It’s  possible  that  tickling  is  interpreted  as  a  threat  and  the  laughter  is  a  social  signal  of  submission  to  prevent  us  from  getting  hurt  or  to  defuse  a  scary  situation.