That's the thrust of this paper by J. Pankseep et al (hat tip: Mind Hacks). It grounds the field of evolutionary psychology by holding some of its claims to the same scientific standards necessary in other fields of evolutionary research.
One of the primary points of the paper is that human changes in brain-based behavior may be due to epigenetics and cultural selection (through exaptation, perhaps), and are not solely attributable to natural selection.
It also looks at the HPA axis and evaluates its role in regulating social interactions in animal models. It stresses the "resident-intruder" experimental set-up in rats, in which the intruder is almost always the "loser" of the social interaction and exhibits physiological changes following this defeat, including loss of weight, testicular regression, and increased fearfulness. These changes are especially evident when the "loser" rat is not placed back in a social housing condition but is instead housed in isolation. While we should be careful not to excessively generalize these findings to humans, they are obviously exciting.
Well worth a read for those interested in either field.