It is interesting for me to learn how much the tree shrew can tell us about human nature. They were one of the first primates on the evolutionary branch leading to humans. Neuro-anatomical studies reveal that they were also the first primate to evolve a highly elaborate and differentiated visual system. Psychological tests show that this development gave rise to the ability to perform two tasks with equal skill: 1) focusing attention on interesting features (while filtering out irrelevant information) and 2) swiftly shifting attention to other interesting (or alarming) features in the environment.

We take these contributions for granted now, but both abilities were not equally present in mammals before the tree shrew. It is an adaptation that had survival value, allowing them to track prey without losing sight of their predators – a trick of nature that makes them equally suited to act as hunters, as well as survive being hunted as prey. We appreciate these contributions when something goes wrong, resulting in one form of attention deficit or another. I think we owe an enormous debt of gratitude to these little beings. They mark the beginning of neocortical evolution in man.