2. Ibid; and Wilkerson, R. G., and K. Pickett, The Spirit Level: Why More Equal Societies Almost Always Do Better (London: Allen Lane, 2009).

3. Stone, C., D. Trisi, A. Sherman, and B. Debot, “A Guide to Statistics on Historical Trends in Income Inequality,” Center on Budget and Policy Priorities, updated October 26, 2015, http://www.cbpp.org/research/poverty-and-inequality/a-guide-to-statistics-on-historical-trends-in-income-inequality.

4. Pickett, K. E., and R. G. Wilkinson, “The Ethical and Policy Implications of Research on Income Inequality and Child Well-being,” Pediatrics 135 Suppl. 2 (March 2015): S39–47, doi:10.1542/peds.2014–3549E.

5. Mayer, E. A., et al., “Gut Microbes and the Brain: Paradigm Shift in Neuroscience,” Journal of Neuroscience: The Official Journal of the Society for Neuroscience 34, no. 46 (November 12, 2014): 15490–15496. doi:10.1523/ JNEUROSCI.3299–14.2014; Picard, M., R, – P. Juster, and B. S. McEwen, – “Mitochondrial Allostatic Load Puts the ‘Gluc’ Back in Gluco-corticoids,” Nature Reviews. Endocrinology 10, no. 5 (May 2014): 303–310. doi:10.1038/nrendo.2014.22; and Picard, M., et al., “Chronic Stress and Mitochondria Function in Humans,” under review.

6. Varela, F. J., E. Thompson, and E. Rosch, The Embodied Mind (Cambridge, MA: MIT Press, 1991).

7. “Zuckerberg: One in Seven People on the Planet Used Facebook on Monday,” Guardian, August 28, 2015, http://www.theguardian.com/technology/2015/aug/27/facebook-1bn-users-day-mark-zuckerberg, accessed October 26, 2015. “Number of Monthly Active Facebook Users Worldwide as of 1st Quarter 2016 (in Millions),” Statista, http://www.statista.com/statistics/264810/number-of-monthly-active-facebook-users-worldwide/.