Promoting Early Language Development Through Parent-child Book Reading in Costa Rica

The purpose of this study is to analyze the effect of an interactive parent-child book reading intervention. The intervention includes two components: the provision of five children's books to parent-child dyads and information about how to practice interactive book reading. The investigators expect to find an effect of this intervention on a) infants' expressive vocabulary, b) reading activity, c) parental expectations and knowledge about language development and d) parental use of interactive book reading strategies.

The foundations of optimal health, growth and development are forged early in life, when income-related gaps in learning opportunities already exist in Costa Rica. It is therefore important for the government to mitigate the effects of these gaps through programs targeting the development of academic, behavioral, socioemotional and economic abilities. Key to the success of such programs is to consider physical health, nutrition, responsive care and early learning. Multiple government-led initiatives in Costa Rica had been carried out in order to provide adequate programs for infants and young children. Evidence of these efforts are observed in the low rates attained in infant mortality, malnutrition and anemia, as well as the high coverage of the current immunization program. However, policies targeting early learning in children under 36 months of age are incipient and government initiatives in this regard are relatively recent.

The purpose of this study is to promote early language development, a central component of early learning. Our goal is to implement and evaluate a low-cost intervention targeting parents of infants who benefit from the existing immunization program of the public health services offered by the Caja Costarricense del Seguro Social (Costa Rican Social Security Fund).

The investigators will use an experimental design to randomly assign 15- to 17-month-old infants and their caregivers to one of two groups: a control group or an experimental group. In the experimental group, caregivers will receive a package including five children's books and 36 text messages with information on how to practice interactive book reading with their children. This information will be delivered over a period of 12 weeks. The control group will not receive any treatment during the implementation of the intervention.

In order to measure the efficacy of the intervention, the investigators will evaluate a) infants' expressive vocabulary, b) parent-child reading activity, c) parental expectations and knowledge about language development and d) parental use of interactive book reading strategies at baseline (15-17 months of age) and at posttest (18-20 months of age) in the control and the experimental group. After posttest, the control group will receive the complete intervention.

The investigators expect to find an effect of the interactive book reading intervention on a) infants' expressive vocabulary, b) reading activity, c) parental expectations and knowledge about language development and d) parental use of interactive book reading strategies.

Eligibility Criteria:
Inclusion criteria for infants:

* Age limits: 15 months to 17 months.
* Sex: All.
* Infant was born full term (≥ 37 weeks).
* Infant is raised in a monolingual Spanish-speaking home.

Inclusion criteria for mothers:

* Mother knows how to read and write.
* Mother has access to cell phone with internet.

Exclusion Criteria:

* Neither caregivers nor infants must have any significant known physical, mental or learning disability.