Why do we close our eyes every 18 seconds?

We do not close our eyes every 18 seconds; or any such arbitrary number. read more

We are awake in general for about 16 hours per day which is 57,600 seconds, so the brain receives from the eyes about 10 trillion or 10^13 informations bits per day. Under extreme conditions the the human brain can stay awake for longer than this, but its performance degrades significantly and becomes unusable at a week (168 hours) of wakefulness. read more

Cuz we are pathetic and like children want to cry. No seriously, if you were a trained martial artist or ELITE soldier, your tolerance to pain can be so much higher that something that superficial won't make you flinch. You get punched in the face and your eyes will water, a boxer getting punched in the face is ready for his next move. read more