„I made no further tests, as I consider it quite obvious that results are determined simply by the technical accuracy of the photographs and the difference of the objects they represent. Anyone who may take the trouble to experiment on other chimpanzees in the same way, will be able to demonstrate effectively and exactly, by means of larger and clearer reproductions, that the animals recognize and differentiate between such photographs.“
The above quote is the closing paragraph of Wolfgang Köhler's classic The Mentalities of Apes, published in 1925. Köhler was a psychologist who conducted experiments and observations on chimpanzees, and is considered one of the founding fathers of cognitive primatology. He chose to look at chimpanzees' performance with pictures after having observed their fearful reactions to stuffed toy animals and cardboard face masks. He observed that it seemed necessary for the toy animals to have some likeness to real animals, “nearness to life,“ in order to invoke fear. The stuffed animals invoked even stronger responses than did most real animals. He concluded that the stuffed animals, not being fully real, played on the imagination in a way that real animals did not.
Simple Picture Experiments
Interpreting, or „filling in“ what is not there, is one definition of imagination. Animals have long been thought not to be able to move beyond what is directly in front of their senses, and proving imagination has thus far-reaching importance. Pictures have been used as stimuli since the early days of animal cognition research to assess questions of for example categorisation; which objects do animal group as „similar“ at the expense of other objects? Pictorial stimuli have been used with such success that few scientists have asked the questions of why they work, and what it means. Since animals of all kinds readily accept pictures as examples of real-world objects, it must mean that pictures are simple and intuitive phenomena. This idea easily lends itself to the conclusion that there are only two ways of viewing pictures: you either recognize them or you do not. This destiny was apparent already in the quote above.
Köhler's picture experiments were simple. He developed a photograph of an empty crate and another photograph of a crate full of bananas, and pasted these on two boxes baited with fruit. Results were mixed. Only one chimpanzee reliably chose the banana photograph. Köhler then created two new photographs: one of bananas and one of a rock. The subjects now performed much better, which Köhler ascribed to the superior quality and nearness to life in the second pair of pictures. However, from the point of view of our own experience a distorted photograph is not necessarily more difficult to recognize than one that depicts reality more truthfully. Adult humans readily decode pictures that are far removed from the real perceptual world, like cartoons. We can even intend to see likeness where there is not supposed to be any, like faces in the clouds.