Piaget on Piaget, Part 3

Summary

An adult examiner asks a child to build a block house on an island-shaped base with the same amount of “room” inside as a model house. At first, the child says the houses have equal room because they look the same size. When asked to compare them more carefully, the child notices that the new house is thinner and judges that the model contains more room.

The child adds blocks to make the new house taller, then tries to decide whether the houses now have equal amounts of room. Initially unsure, the child explains that the added height makes the house match a square-shaped measure. The examiner asks the child to show how the comparison works. The child uses lines or block-sized units to compare parts of the houses, but recognizes that not all sides have been accounted for and says more units must be added. The excerpt ends while the comparison is still underway.

Main Ideas and Method

• The task tests judgments about spatial volume. The child must build a house that fits on the island and has as much room as the model.
• The examiner uses open-ended prompts rather than supplying a solution. The examiner asks the child to build an equally roomy house, compare the houses, explain how they know whether the rooms are equal, and demonstrate the basis for their judgment.
• The child’s reasoning develops during the task:
  • The child first relies on an overall visual impression.
  • The child then notices a difference in thickness and judges the houses to be unequal.
  • The child adds height to increase the space in the smaller house.
  • The child begins using a square and lines or units to compare dimensions.
  • The child realizes that the comparison is incomplete until the remaining sides are measured too.
• The excerpt shows how follow-up questions can reveal a child’s reasoning. The child moves from an intuitive judgment toward an explicit, though unfinished, measurement strategy.

Speakers and Sources

• Adult examiner/interviewer: Guides the block-building task and asks questions; not identified by name in the subtitles.
• Child participant: Builds the house and explains their judgments.
• Other audio: Brief music and snippets of indistinct speech.