A growing literature establishes that high quality early childhood interventions targeted toward disadvantaged children have substantial impacts on later life outcomes. Little is known about the mechanisms producing these impacts. This paper uses longitudinal data on cognitive and personality traits from an experimental evaluation of the influential Perry Preschool program to analyze the channels through which the program boosted both male and female participant outcomes. Experimentally induced changes in personality traits explain a sizable portion of adult treatment effects. Keywords cognitive traits; personality traits; externalizing behavior; academic motivation; factor analysis; human capital; human development; early childhood interventions; social experiments; Perry Preschool program; experimentally estimated production functions A growing literature establishes that early childhood environments substantially impact later life outcomes (e.g., Knudsen et al., 2006 and Almond and Currie, 2011. Less is known about the channels through which early environments operate to produce their long term effects. This paper examines the sources of the success of the Perry Preschool program, a flagship early childhood intervention in the US. 1 The Perry program was a randomized trial that targeted disadvantaged, low IQ African American children ages 3-4. After two years, all participants left the program and enteredCorrespondence to: Peter Savelyev. The paper was presented at a Public Policy and Economics Seminar at the Harris School, University of Chicago, October, 2009, attended by Diane Schatzenbach. 1 The formal name of the program is the "HighScope Perry Preschool Program" (see Schweinhart et al., 2005).
NIH Public Access
NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript the same public school. Data were collected for treatment and control groups through age 40. Heckman et al. (2010a) and Conti et al. (2012) show that the Perry program significantly enhanced adult outcomes including education, employment, earnings, marriage, and participation in healthy behaviors, and reduced participation in crime. 2 We summarize many of these findings in Table 1. All treatment effects displayed there are statistically significant and survive adjustments for multiple hypothesis testing. 3 Heckman et al. (2010b) show that the internal rate of return to the program for both boys and girls is a statistically significant 6-10 percent per year-above the historical return to equity. 4 Positive effects of the Perry program have become a cornerstone of the argument for preschool programs (e.g., Shonkoff and Phillips, 2000). Currently, about 30 percent of all Head Start centers nationwide offer a version of the Perry curriculum (ICPSR, 2010). 5 Previous studies of Perry focus on estimating treatment effects and do not attempt to explain their sources. 6 This paper identifies the psychological skills changed by the Perry program and decomposes the treatment effects on adult outcomes displayed in T...