This is Volume XXI of thirty-two in a series of Developmental Psychology. Originally published in 1946, it looks the classification and seriation and the growth of logic in young children and this study incorporates the results obtained from the examination of a total of 2,159 children.

This is Volume XXI of thirty-two in a series of Developmental Psychology. Originally published in 1946, it looks the classification and seriation and the growth of logic in young children and this study incorporates the results obtained from the examination of a total of 2,159 children.

This is Volume XXI of thirty-two in a series of Developmental Psychology. Originally published in 1946, it looks the classification and seriation and the growth of logic in young children and this study incorporates the results obtained from the examination of a total of 2,159 children.

This is Volume XXI of thirty-two in a series of Developmental Psychology. Originally published in 1946, it looks the classification and seriation and the growth of logic in young children and this study incorporates the results obtained from the examination of a total of 2,159 children.

This is Volume XXI of thirty-two in a series of Developmental Psychology. Originally published in 1946, it looks the classification and seriation and the growth of logic in young children and this study incorporates the results obtained from the examination of a total of 2,159 children.

This is Volume XXI of thirty-two in a series of Developmental Psychology. Originally published in 1946, it looks the classification and seriation and the growth of logic in young children and this study incorporates the results obtained from the examination of a total of 2,159 children.