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. Author manuscript; available in PMC: 2012 Oct 1.
Published in final edited form as: Psychol Sci. 2011 Aug 26;22(10):1288–1295. doi: 10.1177/0956797611420729

Table 1.

Characteristics of the Subjects in the Study

Group n Age (mean in
years)		 Income
bracket (mean)		 Married (%) Employed (%) Number of
children (mean)		 Age of
infant (mean
in months)
Exclusively breast-feeding mothers 18 26.8a (4.04) 3.59a (2.43) 100 6a 2.52 (1.12) 3.93 (0.58)
Formula-feeding mothers 17 26.1a (5.07) 3.28a (1.67) 100 50b 2.52 (1.12) 4.30 (1.06)
Nulliparous women 19 21.1b (1.78) 1.84b (1.92) 26 84b — —

Note: Standard deviations are shown in parentheses. Each subject’s household income was categorized into one of eight brackets (1 = under $10,000; 2 = $10,000–$24,999; 3 = $25,000–$39,999; 4 = $40,000–$54,999; 5 = $55,000–$69,999; 6 = $70,000–$84,999; 7 = $85,000–$100,000; 8 = over $100,000). Employment is reported as the percentage of people in each group who were employed outside the home at the time of the experiment. Within each column, values with different subscripts are significantly different (p < .05).