Baby Play Study
Toddlers learn a lot by interacting with the people and objects in their environments.  In this study, we’re videotaping children in their homes to find out more about their day-to-day activities and how these might contribute to conceptual development.  Families are recorded for three one-hour sessions, every three months.  Scheduling the visits is easy — we can work around each family’s individual schedule.  Participating families receive copies of their child’s videotapes to keep.

Number Similarity Study
Children can group objects in terms of color, shape, or size, but how do they learn to group sets in terms of number?  In this study, we compare two kinds of training to see which experiences help children abstract numerical equivalence.  In one condition, children get lots of practice comparing sets with many different similarities (for example, two red balloons = two red balloons).  In the other, children get lots of practice comparing sets that have only number in common (for example, two green turtles = two red balloons). There are different theories about how children learn to categorize objects.  We’re hoping to find out which of these theories also explains how they learn to categorize sets with the same number.  This is a skill that normally develops in children by age four, so we’re looking for three-year-olds to participate in our study.  All participating children will receive a small prize.

Size Effect Study
Many number skills appear early in development.  However, these skills don’t seem to emerge at the same time for every number — even the very small numbers.  In other words, children seem to understand two before they understand three, and three before they understand four.  In this study, we take a closer look at these set size effects by measuring two-year-olds’ performance on a variety of number tasks over a period of six weeks.  We’re hoping that, by tracking children’s errors on various tasks, we’ll learn more about the way number concepts are constructed.  All participating children will receive a small prize.

One-to-One Toys Study
We’ve found that children naturally engage in play that has the potential to promote number concepts.  In particular, they like to match items one-to-one.  But we don’t know for sure if these activities actually help children learn about number without more direct testing.  In this study, we give three-year-olds specific toys to play with in their homes, and then test whether this exposure leads to conceptual change.  Pre-tests and post-tests will be administered at the child’s preschool.  Toys will be delivered to each child’s home every two weeks, and parents will be asked to record the amount of time their child plays with each of them.  All children will receive a small prize for participating.