ABSTRACT
Humans depend heavily on visual pattern recognition processes laid out along ventral brain pathways. Starting in area V1 at the rear of the occipital lobe, visual information proceeds in "feed forward" fashion through a loose series of processing stages.
V1 extracts features like line slants and colors. Just forward, V2 processes an object's overall contour and separates it from the background. VP and V3 process general form. These are found in placental mammals but not marsupials, suggesting an origin about 160 million years ago. V1 is found in all mammals, originating over 170 million years ago.
V4 is sensitive to general form and color combinations; for example, an abstract red "squashed raindrop". The next area, LOC/IT, responds to 2D, 3D, and moving patterns, and originated sometime before 32 million years ago.
Particular object classes, such as faces or flowers, are processed by small patches in the fusiform gyrus bridging the occipital and temporal lobes. Similar ones are found in monkeys. Notably, orientation sensitivity is found in face patches, with upright faces providing more configural information than inverted ones. Found to varying degrees in humans, apes, monkeys, and -- counterintuitively -- sheep, it is not found in birds, and may therefore date to 95-300 million years ago.
A related human phenomenon is bias toward global processing (overall shape) and away from local processing (features). Chimpanzees show this to some degree, but not Old World monkeys. New World monkeys demonstrate the reverse, favoring local processing. Thus over the past 32 million years, there has been a striking evolutionary shift in our ancestral line.
Bigger, more interconnected brains may be better at "Seeing the forest before the trees". That may have helped us detect camouflaged prey and predators, and likely improved our global imagery of tools assembled from local parts.
