Each child was interviewed individually. The children were told the entire interview would be recorded, were show how the tape recorder worked, and were told they could hear a playback if they wished. The presence of the recorder gave no visible stress to any child.
Each child was presences with 17 tasks in the same order.
The questions posed were repeated, and key words were repeated whenever it seemed desirable to enable the child to perform at maximum level.
Each child was given as much time as was needed to respond or to admit inability to deal with the problem.
The purpose of the interview was to find out how the children would respond to the tasks, not to compare them under absolutely controlled standardized conditions.
Interviews ranged from 20 to 30 minutes in duration. All interviews were conducted by the author within a 3-week period during the first month of school.
Base-ten "long" and "units" (Dienes, 1960) were available to the child. If a child did not spontaneously use the material, a suggestion to use the blocks was made.
However, no attempt was made to teach the concepts and operations being investigated through the use of blocks, and no leading questions were asked in present the situations.