What's the Use of Picture Discrimination Experiments?

The author introduces a very different view of picture-object correspondence than the focus article. The major motivation of most experiments on the discrimination of picture sets by pigeons has been to gain an understanding of what sorts of categories are discriminated, and how it is done. Researchers with an interest in object representation use discriminations between sets of pictures of natural objects because those sets are likely to have the same structure, in terms of relative similarities, as the sets of views of a particular natural object that the bird will experience in normal life. Indeed, sets of pictures are very likely to offer a better model of the structure of such categories than artificial categories. It is in this sense, and not because of an expectation that the birds will recognize the objects they represent, that they are more ecologically valid than abstract patterns.