D. J. Langford et al., “Social Modulation of Pain as Evidence for Empathy in Mice,” Sci 312 (2006): 1967.
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M. Tomasello and V. Amrisha, “Origins of Human Cooperation and Morality,” Ann Rev Psych 64 (2013): 231; D. Povinelli et al., review of Reaching into Thought: The Minds of the Great Apes, ed. A. E. Russon et al., TICS 2 (1998): 158.