1. In all we experimented with 56 children, but with 27 children, 4 to 7 years old no comparable numerical results were obtained.
2. In these experiments, as well as in the halving and doubling experiments the subjects (adults) were urged to refrain from any explicit measurements and to follow their first impressions. Without these precautions, and with sufficient time for comparison, the subject can very easily correct the illusion (cp. p. 312). This possibility of easy correction probably accounts for the negative results ofBolton concerning the rôle of the contour in producing the illusion of area.Frederick E. Bolton, A Contribution to the Study of Illusions. (b) The Effect of Contour upon Estimation of Area, Amer. J. Psychol.9, 165 (1897–1898).
3. Children sometimes actually did this.
4. With the adults the use of this method again decreases in favor of intuitive comparison, probably owing to different instructions (cp. p. 306).
5. This method of reshaping the figure was very often observed in the experiments in which a figure had to be matched with an equal figure of different shape (cp. p. 310). The children tried to make a square into a rhombus by ‘pulling out’ in imagination two of its corners, and correspondingly to convert rhombi into squares by ‘pushing’ them together.