What does "organic development," mean? There is good evidence that in organic development, perception starts with recognizing outstanding structural features. For example, when two-­year-­old children and chimpanzees had learned that, of two boxes presented to them, the one with a triangle of a particular size and shape always contained attractive food, they had no difficulty applying their training to triangles of very different appearance. The triangles were made smaller or larger or turned upside down. A black triangle on a white background was replaced by a white triangle on a black background, or an outlined triangle by a solid one. These changes seemed not to interfere with recognition. Similar results were obtained with rats. Karl Lashley, a psychologist, has asserted that simple transpositions of this type are universal in all animals including humans.