Although professional development is widely used to improve the impacts of early childhood education, little is known about the conditions under which such interventions promote child outcomes. This study applies newly developed methods for quantifying intervention impact heterogeneity to understand whether educators' collective workplace stress…

Extensive research has explored the ability of young children to learn about the causal structure of the world from patterns of evidence. These studies, however, have been conducted with middle-class samples from North America and Europe. In the present study, low-income Peruvian 4- and 5-year-olds and adults, low-income U.S. 4- and 5-year-olds in…

This training study investigates how children learn to refer to things unambiguously. Two hundred twenty-four children aged 2.6, 3.6, and 4.6 years were pre- and post-tested for their ability to request stickers from a dense array. Between test sessions, children were assigned to a training condition in which they (a) asked for stickers from an…