Piaget's Conservation Task and the Influence of Task Demands

Overview

Source: Laboratories of Judith Danovitch and Nicholaus Noles—University of Louisville

Jean Piaget was a pioneer in the field of developmental psychology, and his theory of cognitive development is one of the most well-known psychological theories. At the heart of Piaget’s theory is the idea that children’s ways of thinking change over the course of childhood. Piaget provided evidence for these changes by comparing how children of different ages responded to questions and problems that he designed.

Piaget believed that at age 5, children lack mental operators or logical rules, which underlie the ability to reason about relationships between sets of properties. This characteristic defined what he called the preoperational stage of cognitive development. One of Piaget’s classic measures of children’s ability to use mental operations is his conservation task. In this task, children are shown two identical objects or sets of objects. Children are first shown that the objects are the same on one key property (number, size, volume, etc.). Then, one of the objects is modified so it appears different than the other one (e.g., it is now longer, wider, or taller), but the key property remains the same. Following this transformation, children are asked to judge if the two objects or sets of objects are now the same or different with respect to the original key property.

Piaget reported that children in the preoperational stage (approximately ages 2-7) typically judged the objects to be different after the transformation, even though the key property had not changed. He attributed children’s incorrect responses to their excessive focus on the change, rather than on the fact that the key property remained the same. However, over the years, researchers have argued that Piaget’s conservation task is an invalid measure of children’s reasoning skills. These critics have suggested that children’s poor performance is due to task demands, such as assumptions about the experimenter’s goals and expectations when the question about the key property is repeated.

This video demonstrates how to conduct Piaget’s classic conservation task,^1–2 and how a small modification in the task design can dramatically change children’s accuracy (based on the methods developed by McGarrigle and Donaldson³).

Procedure

Recruit 4- to 6-year-old children who have normal vision and hearing. For the purposes of this demonstration, only two children are tested (one for each condition). Larger sample sizes are recommended when conducting any experiments.

1. Gather the necessary materials.

Obtain two sets of four small tokens. For this experiment, use four red checkers and four blue checkers.
Obtain two 10 in (25.4 cm) pieces of string or yarn of different colors. For this experiment, use blue

Results

Researchers tested 20 4- through 6-year-old children and found that children in the accidental condition were much more likely to judge the number or length of the objects had stayed the same after the transformation (Figure 1). Children in the intentional condition performed very poorly (12% correct responses) compared to children in the accidental condition (62% correct). The intentional condition in this study corresponds to Piaget’s original method for the conservation task. Thus, this pattern

Application and Summary

This demonstration illustrates how task demands can affect the outcomes of psychological research, particularly in young children. The assumptions children make when an adult is talking to them and asking difficult questions may not always be obvious, but they can have a major influence on how children respond. This finding is important not only for researchers, but also for educators, parents, and other people who may be in situations where they are measuring a child’s skills or questioning a child about an event.

References

Piaget, J. The Child’s Conception of Number. Routledge and Kegan Paul. London, England (1952).
Piaget, J., & Inhelder, B. The Psychology of the Child. Basic Books. New York, New York (1969).
McGarrigle, J., & Donaldson, M. Conservation accidents. Cognition. 3 (4), 341-350 (1975).