"Wait untill you see the whites of their eyes!", is the iconic battle cry of the commander under siege as the attackers come in mass upon the fort, circle of wagons or up the hills toward his men.
Strangely, the large whites of the eyes in human where designed to help us cooperate.
Recent research at Max Planck Institute for Evolutionary Anthropology discovered that unlike chimps and apes who look at head movement, children pay more attention to eye movement.
Apes and chimps need to mask where they are looking looking from other primates and thus do not have those bright whites of the eyes. Anthropologist Brain Hare says primates who do not have bright whites can hide where they are looking from others so they can, "...eat it, mate it, or chase it," I am thinking the chasing might come first, but I digress.
Humans however have evolved the bright whites of the eyes to contrast with our baby blues Iris and dark pupils so we can easily see the direction of another person's gaze.
The theory is that the advantages of understanding and cooperation received through mutual gaze outweigh a having a poker face. This is particular useful to me as I am not a great poker player, but boy can I read that body language.
I think this also interesting if your apply all the information we get subconsciously from eye gaze and brain function. That is the science of NLP. Which I have blogged about previously. I love that we were designed to create mutual gaze. If your interested in the whites of the eyes research pick up this months Scientific American Mind. Just another fun body language fact.
