A LOT TO DIGEST
Arcimboldo's composite heads demonstrate that, neuroscientifically speaking, the whole can be much more than the sum of its parts. Clever arrangements of individual fruits, flowers, legumes and roots become exquisite portraiture in their entirety, such as in the likeness of the Hapsburg emperor Rudolf II (left), here depicted as Vertumnus, the Etruscan god of transformations, or in the artist's self-portraits as Summer and Autumn (center and right).
The brain builds representations of objects from individual features, such as line segments and tiny patches of color. You see a nose in the Summer portrait not because there is a retinal cell that perceives noses but because thousands of retinal photoreceptors in your eye react to the various shades of color and luminance in that area of the painting. High-level neuronal circuits then match that information to the brain's stored template for noses. The output from those same photoreceptors also activates the high-level object-tuned neurons that recognize turnips, figs and pickles, which is what makes images like these so much fun to look at.
Last but not least, Arcimboldo's masterpieces also bring to mind the old adage that you are what you eat. “Avoid fruits and nuts,” advises Garfield, the cartoon cat created by Jim Davis.