How do children form categories?

    • Topic: Cognitive Development

    • Location: Discovery Center

    Research has shown that children readily group people into categories (e.g. boy and girl, child and adult). However, it is not yet known why children are more likely to form categories such as these rather than others (e.g. tall and short, loud and quiet). It may be because certain categories are more obviously visible, or that these categories are more useful in helping children make predictions about what people will be like. For example, knowing someone’s age might help us make accurate predictions about their hobbies or interests, in a way that knowing someone’s height might not. We are interested in exploring whether usefulness or visual apparentness of a category drives children’s category formation.

    In this study, children (4 – 6 years) will see a few unfamiliar creatures. Children will be asked to group the creatures into categories based on shape, color, or texture. While color and shape are visually striking qualities, it is only texture that will prove to be useful in helping children make accurate predictions about the creatures’ favorite foods and habitats. We will observe whether children form categories based on qualities that are visually apparent (shape or color) or whether they form categories based on what will be most useful in helping them understand the creatures (texture).

    By observing which features children rely on to form categories for the creatures they see in the study, we hope to better understand how children form categories more broadly, including those they identify from the characteristics of people they encounter in everyday life.

    This research is conducted at the Museum of Science, Boston by Paul Muentener, Assistant Professor at Tufts University and the Cognitive Development Laboratory. For more information email

        » Cognitive Development Laboratory at Tufts University

    Activities to Try in the Discovery Center

    Floating and Falling

    Find the Air Table on the 2nd floor of the Discovery Center. Place the clear tube over an air vent. Ask your child to put a large ball without holes on the tube. What happens? Try the same experiment with different balls. Ask your child to observe what happens with each ball. Try testing large and small balls, balls with and without holes, and balls of different colors.

    As you experiment, ask your child to sort the balls into different categories. Does s/he choose to sort the balls into more visual categories (e.g. color) or into categories that help him or her to form predictions about the balls’ behavior (e.g. floats or falls)? How many different ways can your child sort the balls?

    Activities to Try at Home

    Grocery Shopping

    After coming home from a grocery shopping trip, ask your child to help you sort the food you purchased into different categories. Once s/he has finished sorting the groceries, ask your child to explain why s/he made the groups that way. Did your child group the groceries based on visual appearance (e.g. fruits vs. vegetables, big vs. small), or did s/he group the groceries based on the usefulness of the category (e.g. whether or not the item is refrigerated, likes vs. dislikes)?

    Try making your own categories for the groceries, and encourage your child to help you sort the groceries based on those categories. How many different ways can you sort the groceries together?

Research Spotlight

Contact Living Laboratory staff: