American families in North Carolina. Between 1972 and 1977,
investigators randomly assigned four cohorts of infants to an
intensive, full-time early-education program from birth to age
5, or to a control group that didn’t receive services. Then the
researchers followed the children into adulthood.
The investigators found that children who participated in
the program scored higher on tests of cognitive functioning
from toddlerhood through early adulthood. They had greater
academic achievement from the primary grades though young
adulthood, and were more likely to go to college.
The Perry Preschool Project had a similar design, but quite
different findings. It began in 1962, when David P. Weikart,
PhD, a psychologist for the Ypsilanti, Mich., school district, and
colleagues randomly assigned low-income African-American
children to an intensive two-year preschool program or to a
control group that didn’t attend preschool. The researchers
followed those participants into their 40s.
Initially, the results didn’t seem promising. Although
children who attended the program scored higher on
intelligence tests than the control group right after preschool,
those intelligence gains disappeared by elementary school.
However, other benefits materialized in early adulthood. The
program appeared to have positive effects on high-school
graduation rates, adult earnings and crime reduction.
The Perry study seemed to support a view first championed
by Nobel laureate and economist James Heckman, PhD: The
short-term cognitive benefits of preschool may fade, but long-
term social benefits may sprout later in life.
Other studies support the idea that some social benefits
persist even as cognitive gains disappear, says C. Cybele Raver,
PhD, a psychologist and vice provost of academic, faculty and
research affairs at New York University. “I think the field is
starting to shift, offering confirmation of some of the points
that Heckman has raised. Investments in early childhood
reap rewards along the line, in ways that we’re just now really
Not everyone agrees. “The Perry study is a thin reed
on which to develop an all-encompassing theory of early
intervention,” says Grover J. “Russ” Whitehurst, PhD, a child
psychologist with the Brookings Institution and former director
of the Institute of Education Sciences at the U.S. Department
of Education. When it comes to the long-term benefits of early
education, he adds, “I think the evidence is mixed.”