A. Marsh et al., “Oxytocin Improves Specific Recognition of Positive Facial Expressions,” Psychopharmacology (Berlin) 209 (2010): 225; C. Unkelbach et al., “Oxytocin Selectively Facilitates Recognition of Positive Sex and Relationship Words,” Psych Sci 19 (2008): 102; J. Barraza et al., “Oxytocin Infusion Increases Charitable Donations Regardless of Monetary Resources,” Horm Behav 60 (2011): 148; A. Kogan et al., “Thin-Slice Study of the Oxytocin Receptor Gene and the Evaluation and Expression of the Prosocial Disposition,” PNAS 108 (2011): 19189; H. Tost et al., “A Common Allele in the Oxytocin Receptor Gene (OXTR) Impacts Prosocial Temperament and Human Hypothalamic-Limbic Structure and Function,” PNAS 107 (2010): 13936; R. Hurlemann et al., “Oxytocin Enhances Amygdala-Dependent, Socially Reinforced Learning and Emotional Empathy in Humans,” J Nsci 30 (2010): 4999.