Here you will find a description of research projects currently ongoing at the Play Lab, as well as projects that were previously completed. For presentations and publications from these studies, see Publications . Ongoing: Genetic Influences on Early Cognitive Development: Early cognitive development, such as ability to conserve, engage in fantasy, and group similar objects, is studied in 1- to 4-year-old twins. Twins are tested within a month of their birthdays in the play lab. This is a longitudinal study, with twins being tested every year from age 1 (or as early as we can recruit them)