Kagan successfully forces us to re-examine our assumptions and concepts regarding the broad field of “emotion.” His postulated four phases start with the brain state provoked by some stimulus. While that constitutes a reasonable starting point, the specificity of the brain qualities provoked by different types of stimuli remains uncertain. The recommendations on the way forward are the least satisfying aspects of this article. Integration would have been helped by some consideration of the role of animal models, of the ways in which genes operate, and of the multiple varieties of gene—environment interplay.
