Table 1.

Sample characteristics for each of the cohorts

	PAWS	WSFW	SMP	HMP
N	324	120	109	111
Age (years)	M = 5.31 (SD = 0.32)	M = 7.27 (SD = 0.24)	M = 10.37 (SD = 2.60)	M = 12.35 (SD = 0.55)
	Range = 4.75–6.28	Range = 6.80–7.80	Range = 7.01–15.08	Range = 11.09–13.05
Gender (% girls)	N = 157 girls (49%)	N = 73 girls (61%)	N = 57 girls (52%)	N = 58 girls (52%)
Parents with college degree	75%	59%a	66%	NA
Annual household income	Mdn = $80,000–$99,999	Mdn = $49,000	Mdn = $60,001–$100,000	NA
Study tasks	Range = <$10,000–>$400,000	Range = <$10,000–>$200,000	Range = <$15,000–>$200,000
Lab challenges	15-min stress paradigm	15-min stress paradigm	TSST-M	1. Star tracing/reaction time tasks
				2. TSST-C
Baseline activities	Neutral activities	Neutral stories	Casual conversation	1. Relaxing video
				2. Casual conversation
Measures
Autonomic nervous system PEP (SNS), RSA (PNS), HR	Collected continuously during reactivity protocol and neutral activities	Collected continuously during reactivity protocol and neutral stories	Collected continuously during casual conversation and TSST-M	Collected continuously during start tracing and reaction time task and video
HPA axis Salivary Cortisol	Collected before and after reactivity protocol	Collected before and after reactivity protocol	Collected before and repeatedly after TSST-M	Collected before and repeatedly after TSST-C

Note: The stress paradigm included a brief social interview, the digit span, a sensation test, and watching emotional videos (Boyce et al., 2001; Quas et al., 2004). PAWS, Peers and Wellness Study; WSFW, Wisconsin Study of Families and Work; SMP, Stress and Memory Project; HMP, Hearts and Minds Project; TSST, Trier Social Stress Test (Kirschbaum et al., 1993); SNS, sympathetic nervous system; PEP, preejection period; RSA, respiratory sinus arrhythmia; HR heart rate; HPA, hypothalamic-pituitary-adrenal. The TSST-M (Yim et al., 2010) required children give a speech about themselves and complete mental arithmetic. The TSST-C (Buske-Kirschbaum et al., 1997) required children answer questions about a story and complete a mental arithmetic.

^aFor WSFW, the percentage corresponds to mothers.