His assessment of Samoan kinship was subsequently challenged by Derek Freeman, long before the now-famous Mead–Freeman controversy about Samoa.

[3] At the National Institute of Mental Health Embler worked on the universality of the familial incest taboo.

After evaluating the various explanatory hypotheses of the time, his own empirical research confirmed that much of the variation in cousin marriage could best be explained as an adaptation to the harmful effects of inbreeding.

Traditional theories had focused on economic factors, such as which gender contributed most to the economy, but finding these explanations lacking in predictive value, Ember began to explore other possibilities, particularly the effects of warfare in the social environment.

[6] Believing that laws about human nature should hold true among technological complex as well as simpler societies, he persuaded political scientist Bruce Russett to join him and his wife Carol R. Ember in a project to test the theory that “democracies do not fight each other”.

[7] Although the concepts of democracy and international war had to be transformed to fit the anthropological record, the results of their collaborative research were consistent with many studies conducted by political scientists.