Humans evolved from tree-living ancestors who needed exceptional vision to survive high above the ground. Those with bad eyesight must have misjudged where fruit and blossoms hung, then missed their mark as they leapt from one branch to another and fell and broke their necks. As a result, all higher primates have large brain regions devoted to the perception and integration of visual stimuli. In fact, for decades psychologists have emphasized the important role of visual appearances in stimulating feelings of romantic attraction.
