This kind of makes sense, to me at least. In terms of evolution, brains build out from the center 'older' parts, outward. Newer parts of the brain can overrid

This kind of makes sense, to me at least. In terms of evolution, brains build out from the center 'older' parts, outward. Newer parts of the brain can override behaviors of older parts. Reptilian brain (Trust nothing) -> Mammalian brain (Trust family) -> Primate brain (Trust clan) -> Human brain (Trust all those who may help) -> Trusting is probably a very computationally demanding system of the brain. However, if one is able to trust wisely, one may also expand one's fitness.