Beiträge zur Psychologie der Gestalt

Summary

By presenting dark figures on a light ground these experiments not only avoided the criticism leveled at the method of producing γ-movement, but actually proved Engel's accusation false. Since his claim was specific the results could be equally decisive: if a black figure comes with expansion then it can not be the influence of the field that is affecting it, since that influence has been described by Engel as of the opposite nature. The black disc, when it was a figure breaking into a homogeneous ground, in every case and for every subject appeared with marked expansion. So much for the first claim. The experiments with the rings, though giving in the main the same results have needed more careful consideration and explanation, but have nevertheless brought out everywhere that the figure-property of the ring is the decisive factor, and not the brightness changes in the ground. More might have been done on the voluntary attention paid to one or other of the figures, and to the effects of relative intensities, but the chief results of the experiment are without question; a black figure appears with expansion and a white one will disappear with contraction, despite increase of field intensity. The main determinants of γ-movement are in the relation of figure to ground, and not those of change of brightness.