Illustrated above is a deep-water marine fish belonging to the family Gonostomatidae. More commonly known as bristlemouths, Gonostomatidae are easily the most plentiful vertebrates on on the planet. How many are we talking? Have a guess; I bet you’ll underestimate. (I certainly did.)
Let's just say it involves child-parent relations that would make Oedipus blush.
You'll notice right away that choosing the correct side without counting the fish individually is pretty tough. This difficulty stems from the fact that humans can only assess relative quantities by snap judgment under certain conditions. Take away six fish from the right-hand side, for example, and this task becomes…