878 vIII. EMERGING  ISSuES AND  NEW  DIRECTIONS
(Steps to Achieving Resilience), a program 
that randomly assigned kindergartners and 
teachers to classes of different sizes, yields 
results similar to the Perry Program. Using 
data from Project STAR, Dee and West 
(2011) found that assignment to a small 
class is associated with positive changes in 
personality. In a follow-  up analysis, Chetty 
et al. (2011) examined Project STAR and 
found that students placed in higher-  quality 
kindergarten classes—  as measured by their 
peer’s average performance on a Stanford 
Achievement Test—had significantly higher 
earnings in early adulthood.
The curriculum Promoting Alternative 
Thinking Strategies (PATHS) teaches self-  
control, emotional awareness, and social 
problem-  solving skills, and is aimed at el -
ementary school children (see Bierman et al., 
2010). A recent random assignment, longi -
tudinal study demonstrates that the PATHS 
curriculum reduces teacher and peer ratings 
of aggression, improves teacher and peer 
ratings of prosocial behavior, and improves 
teacher ratings of academic engagement.77 
PATHS is an exemplar of school-  based social 
and emotional learning (SEL) programs. A 
recent meta-  analysis found that such school-  
based programs improved grades by 0.33 
standard deviations and achievement test 
scores by 0.27 standard deviations (Durlak, 
Weissberg, Dymnicki, Taylor, & Schellinger, 
2011).78 Likewise, several random assign -
ment evaluations of Tools of the Mind, a pre -
school and early primary school curriculum 
targeting development of self-  control, show 
that it improves classroom behavior, as well 
as executive function, defined as higher-  level 
cognitive skills including inhibitory control, 
working memory, and cognitive flexibil -
ity (Barnett et al., 2008; Barnett, Yarosz, 
Thomas, & Hornbeck, 2006; Bodrova & 
Leong, 2001; Diamond, Barnett, Thomas, & 
Munro, 2007; Lillard & Else-Quest, 2006).79 
Positive findings are reported for the Mon -
tessori preschool curriculum (Lillard & Else-
Quest, 2006). Unlike the Perry study, these 
studies do not have long-term follow-  ups.
There is evidence that targeted interven -
tion efforts can improve preferences and 
skills. In contrast to the multifaceted cur -
ricula described earlier, studies targeting 
improvement in aspects of conscientious -ness are designed to isolate a particular 
mechanism producing behavioral change. 
In early work, Rueda, Rothbart, McCan -
dliss, Saccomanno, and Posner (2005) de -
signed a set of computer exercises to train 
attention in children between ages 4 and 6 
years. Children in the intervention group 
improved in performance on computer tasks 
of attention relative to children who instead 
watched interactive videos for a comparable 
amount of time. Similarly, Stevens, Fanning, 
Coch, Sanders, and Neville (2008) designed 
a 6-week computerized intervention and 
showed that it can improve selective audi -
tory attention (i.e., the ability to attend to 
a target auditory signal in the face of an ir -
relevant, distracting auditory signal). While 
yielding interesting preliminary results, 
these programs had only short-term follow- 
ups and involved very small samples.
A recent strand of research has focused on 
testing and implementing interventions on 
a larger scale and directly in school. Alan 
and Ertac (2018) claim that an intervention 
in Turkey designed to encourage forward- 
looking behavior by increasing the salience 
of future selves improves patience measured 
on experimental tasks. The effect has per -
sisted and 3 years later, is associated with 
an improved “behavior grade” for girls 
and high-  achieving students. However, the 
study is badly flawed and has to be taken 
with more than the usual grain of salt. Kosse 
et al. (2020) showed that social skills may 
also be impacted. They studied a mentor -
ing intervention program in Germany that 
randomly paired children from low-  income 
families with college student mentors. Before 
the intervention, children from low-  income 
families scored lower on measures of proso -
ciality. The gap across income groups disap -
peared for the treated group and this effect 
was found 2 years later. Finally, Algan, Bea -
sley, Vitaro, and Tremblay (2014) studied 
a 2-year intervention (implemented at the 
time of entry into primary school) aimed at 
improving noncognitive skills in boys who 
were disruptive in kindergarten. They found 
that it increased self-  control and trust, im -
proved labor market participation, and re -
duced criminal behavior in early adulthood.
Several studies suggest that noncogni -
tive skills can be remediated in adolescence. 