Understanding the bases of complex behavioral phenotypes, such as soci
opathy, is assisted by an evolutionary approach, in addition to other
theoretical perspectives. Unraveling genetic and environmental factors
underlying variant forms of sociopathy remains a key challenge for be
havioral science investigators. Twin research methods (e.g., longitudi
nal analyses; twins reared apart) offer informative means of assessing
novel hypotheses relevant to sociopathic behaviors.