Executive function skills are gaining interest and popularity in early childhood development (ECD) circles around the world. Academic research on executive function and early childhood development is on the rise: the annual output of research papers that included both “executive function” and “early childhood” as keywords more than doubled from 2013 to 2017.
Although most research on executive function skills in early childhood has occurred in high-income countries (HIC), ECD assessments in low- and middle-income countries (LMIC) are increasingly including items that measure executive function skills. For example, the Measuring Early Learning, Quality and Outcomes assessment, and the International Development and Early Learning Assessment both include executive functions and have been implemented in many LMIC. In general, there is a growing recognition that an array of risk factors facing children in LMIC contexts—including malnutrition, inflammation, and infection—have direct effects on children’s neurodevelopmental outcomes, including executive function skills (Suchdev et al., 2017). This has spurred greater interest in measuring these skills in young children in LMIC.
Why Do Executive Function Skills Matter?
The intense interest in executive function skills during early childhood is based on three inter-related ideas. First, executive function skills facilitate children’s ability to “learn how to learn.” Executive function skills are related to multiple indicators of children’s school readiness success (Blair and Raver, 2015; Zelazo, Blair, and Willoughby, 2016). Second, executive function skills can be improved. From a social justice perspective, this implies that efforts to improve these skills among low-income children may help to reduce the gap between low-income students and their peers early in school (Blair and Diamond, 2008). Third, executive function skills undergo rapid development in early childhood (Garon, Bryson, and Smith, 2008). Based on both neural plasticity and return on investment arguments, early childhood has been described as a developmental period in which executive function interventions may be most effective and have the greatest potential for long-term payoff (Heckman, 2007; Johnston, Nishimura, Harum, Pekar, and Blue, 2001).
Reasons to Be Wary…
Although the rationale for focusing on executive function skills in early childhood is compelling, it’s not a silver bullet.
- There is no evidence (yet) for a causal relationship between executive function and school readiness outcomes. Studies that have related executive function skills to school readiness outcomes primarily used cross-sectional or passive longitudinal designs. These types of studies provide a weak basis of inference about a causal role that executive function skills might play in school readiness outcomes (Jacob and Parkinson, 2015). Moreover, many of the ECD studies that have documented intervention effects on executive function skills never directly targeted those skills (Raver et al., 2011; Sasser, Bierman, Heinrichs, and Nix, 2017). We still need studies that conclusively demonstrate that improvements in executive function skills are causally related to improvements in school readiness outcomes for individual children.
- Executive function skills are a necessary but insufficient marker of a broader array of competencies. Multiple domains of children’s behavioral and cognitive development undergo rapid change in early childhood. Studies that focus narrowly on executive function skills risk misattributing the effects of other cognitive processes, for example processing speed, to executive function (Willoughby, Blair, Kuhn, and Magnus, 2018). Many aspects of children’s cognitive, physical and social-emotional development contribute to early learning and early school success, not just executive function skills.
- Executive function skills do not only develop in early childhood. Although executive function skills undergo rapid improvements in early childhood, they continue to develop in middle childhood and beyond (Best, Miller, and Jones, 2009). There is limited empirical evidence that executive function skills develop more quickly in early childhood, or that executive function interventions are more effective if delivered in early childhood than middle childhood. In many LMIC, early childhood education is not compulsory or even widely accessible, so executive function interventions in primary school (middle childhood) might be more easily implemented.
How Should We Proceed?
So how can the global ECD community continue to support research and practice in executive function skills effectively?
First, mind the measurement gap. There is a clear need to accelerate the development and evaluation of culturally-relevant, easy to use, reliable and valid measures of neurodevelopment, including executive function skills, in LMIC contexts.
Second, identify or develop interventions that are appropriate for use in LMIC. It is important to determine which existing interventions from HIC (Diamond and Lee, 2011) are appropriate for use in low resource contexts, and what adaptation of these interventions might be necessary. It may be valuable to develop new intervention approaches for use in LMIC that build on the “active ingredients” of previously successful programs (Diamond and Ling, 2016).
Third, test whether executive function skills improve school outcomes. Experimental studies of interventions that specifically aim to improve executive function skills are a top priority. However, there will also be benefits from testing whether general ECD interventions, including those targeting nurturing care and nutrition among others, result in improved executive function skills. In some instances, it may also be important to test whether interventions are more or less effective depending on a child’s initial level of executive function skills.
We hope the global child development community will join us in seeking answers to these questions and others as we endeavor to improve outcomes for young children globally.