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The Impact of Cognitive Stimulation and Nutritional Supplements on Early Childhood Development in Colombia

Location: Colombia
Sample: 1420 children aged 12 to 24 months
2010 to 2011
Target Group: 
Children under five
Mothers and pregnant women
Outcome of Interest: 
Food security and nutrition
Intervention Type: 
Cash transfers
Early childhood development
Preventive health
AEA RCT Registration Number: 

Governments and NGOs around the world have implemented a variety of early childhood development (ECD) interventions to address the lack of psychosocial stimulation and nutrition faced by disadvantaged children. Researchers in Colombia evaluated two early childhood development interventions at scale that trained mothers to provide their children aged 1–2 with psychosocial stimulation, micronutrients, or both. Psychosocial stimulation improved children’s cognitive development, but micronutrient supplementation had no effect. Combining the two interventions did not create additional benefits beyond stimulation alone.

Policy Issue 

Early childhood is a critical time for cognitive, social, and physical development. For children under the age of five, good nutrition and psychosocial stimulation—physical and emotional engagement—may be especially important for physical and neurological growth. Unfortunately, in developing countries, many children under five fail to reach their developmental potential, due to poverty and the often associated poor nutrition and lack of psychosocial stimulation. Previous research has shown that nutritional supplements early in life can increase a child’s income1 as an adult and that encouraging parents to play with their children more can promote greater emotional and intellectual development.2 Yet there is little evidence on how to successfully scale up early childhood development programs while maintaining impact and cost-effectiveness. To address this gap, researchers used the existing administrative capacity and community networks of a national cash transfer program in Colombia to evaluate the impact of a program that trained low-income mothers to provide their young children with psychosocial stimulation, micronutrients, or both.

Context of the Evaluation 

In Colombia, as in many other countries, children from low-income households often accumulate delays in cognition and language, which can be detected as early as twelve months of age. A 2014 study found that, by age three, the cognitive and language differences between children from middle- and low-income households in Colombia were as large as one standard deviation of a standardized score. In addition, 31 percent of children in the country’s lowest socioeconomic category were anemic, an indicator of malnutrition, in 2010. At baseline, in the comparison group in this study, 46 percent of children were anemic and 16 percent were stunted; participating mothers were about 27 years old on average and had slightly more than a primary school education.

Researchers tested two early childhood interventions that were implemented through the existing infrastructure of Colombia’s largest national welfare program, Familias en Acción. The program provides conditional cash transfers to the poorest 20 percent of Colombian households if their children attend school and regular health check-ups. To promote community participation, beneficiaries periodically elect representatives, “mother leaders,” who act as liaisons between them and local program officials.

Trained home visitor reads with mother and children in Colombia

Details of the Intervention 

Researchers conducted a randomized evaluation to measure the impact of two early childhood development interventions on cognition and physical health, implemented through an existing national welfare program that could facilitate a cost-effective scale-up of these interventions. They randomly assigned 96 Familias en Acción municipalities near Bogotá to one of four groups: a psychosocial stimulation program, a micronutrient supplement program, both programs, or the comparison group. In each municipality, three mother leaders were randomly selected to administer the programs through home visits. Within each mother leader’s constituency (about 50 households), researchers randomly selected five families with children aged 12–24 months to participate in the study, for a total of 1,420 children.

The interventions began in 2010 and lasted 18 months. In municipalities assigned to the stimulation program, home visitors visited mothers every week and demonstrated appropriate play and learning activities for their children using low-cost or homemade toys, picture books, and form boards. In micronutrient municipalities, mother leaders distributed micronutrient supplements to households every two weeks and monitored their use. Municipalities in the third treatment group received both interventions. Home visitors were trained for several weeks by experienced social workers, who also provided home visitors with ongoing support and monitored their performance. Eighty-one percent of scheduled home visits were completed, and 73 percent of scheduled micronutrient supplements were recorded as having been distributed.

Researchers used the Bayley-III scale of infant and toddler development to measure cognitive development. The scale has indicators on cognition, receptive language, expressive language, and motor skills.3 Researchers also measured children’s weight, height, and hemoglobin levels.

Results and Policy Lessons 

Results demonstrated that encouraging mothers to interact and play more with their children significantly improved children’s cognitive development, while micronutrient supplements had no detectable effect. Neither program had an impact on indicators of children’s physical health; combining the two programs did not produce a greater impact on cognition.

The psychosocial stimulation program increased children’s cognition scores by 0.26 standard deviations, and receptive language by 0.22 standard deviations, relative to children of the same age in comparison communities. The size of this improvement equals almost a third of the gap in cognition between children of extremely poor families and children of middle class families in Colombia. Data on young adults in the U.S. suggests that a difference in cognition of this size at age four is associated with a 7.5 percent difference in income by age 30—which is equivalent to the income increase of one extra year of schooling.

To understand what drove these improvements, researchers used the data from the randomized evaluation to model how different factors affected the development of the children in the study. This analysis demonstrated that the improvements in cognitive development were driven by increased parental investment, encouraged by the home visits. Relative to the comparison group, parents in households that received the stimulation program increased material resources and time spent with their children by 24.8 and 36.1 percent, respectively. Results demonstrated that material investments were the primary driver of children’s improvement in cognitive skills, and time investments were important in improving socio-emotional skills.

While the stimulation program caused parents to allocate more of their resources to their children, there was no evidence that the quality of parental investments improved. This suggests that one reason for under-investment in child development might be a lack of knowledge about the effectiveness of these investments; the intervention may have been successful because it changed parents’ beliefs about the usefulness of investing in their children.

Several factors may explain why micronutrient supplements had no impact on children. It is possible that the high levels of anemia in children were not linked to micronutrient deficiency, but to other factors such as chronic infection. It is also possible that the supplements were not distributed as regularly as the records indicate.

This study demonstrates that an early childhood development program encouraging psychosocial stimulation can improve young children’s cognitive development, and provides a model for implementing it at scale in Colombia. At a cost of approximately US$500 per child per year, this program was less than half the cost per child of some of the Colombian government’s flagship early childhood development programs which cost as much as US$1500 per child.

Attanasio, Orazio, Camila Fernández, Emla Fizsimons, Sally Grantham-McGregor, Costas Meghir, and Marta Rubio-Codina. 2014. "Using the Infrastructure of a Conditional Cash Transfer Program to Deliver a Scalable Integrated Early Childhood Development Program in Colombia: Cluster Randomized Controlled Trial." BMJ 349:g5785. 

Attanasio, Orazio, Sarah Cattan, Emla Fitzsimons, Costas Meghir, Marta Rubio-Codina. "Estimating the Production Function for Human Capital: Results from a Randomized Control Trial in Colombia." NBER Working Paper No. 20965, February 2015.

Andrew, Alison, Orazio Attanasio, Emla Fitzsimons, Marta Rubio-Codina. 2016. "Why is Multiple Micronutrient Powder Ineffective at Reducing Anaemia Among 12-24 Month Olds in Colombia? Evidence from a Randomised Controlled Trial." SSM-Population Health, available online 7 March 2016.

1 Hoddinott, John, John Maluccio, Jere Behrman, Rafael Flores, and Reynaldo Martorell. 2008. “Effect of a Nutrition Intervention During Early Childhood on Economic Productivity in Guatemalan Adults.” 371(9610): 411-416.

2 Walker, SP, SM Chang, M Vera-Hernández, and S Grantham-McGregor. 2011. “Early Childhood Stimulation Benefits Adult Competence and Reduces Violent Behavior.” Pediatrics 127(5): 849-57.

3 The Bayley Scales of Infant Development are widely accepted standards used in clinical psychology to measure the development of children aged 0-3. The standards include indicators on levels of cognition, language skills, motor skills, adaptive behavior, and social-emotional skills.