Editing Animal cognition (section)

==== Methods ====
Most work on animal concepts has been done with visual stimuli, which can easily be constructed and presented in great variety, but auditory and other stimuli have been used as well.<ref>{{cite book | vauthors = Dooling RJ, Okanoya K | date = 1995 | chapter = Psychophysical methods for assessing perceptual categories. | veditors = Klump GM, Dooling RJ, Fay RR, Stebbins WC | title = Methods in Comparative Psychoacoustics | pages = 307–318 | location = Basel, Switzerland | publisher = Birkhäuser Verlag}}</ref> Pigeons have been widely used, for they have excellent vision and are readily conditioned to respond to visual targets; other birds and a number of other animals have been studied as well.<ref name="Shettleworth" />
In a typical experiment, a bird or other animal confronts a computer monitor on which a large number of pictures appear one by one, and the subject gets a reward for pecking or touching a picture of a category item and no reward for non-category items. Alternatively, a subject may be offered a choice between two or more pictures.  Many experiments end with the presentation of items never seen before; successful sorting of these items shows that the animal has not simply learned many specific stimulus-response associations. A related method, sometimes used to study relational concepts,  is matching-to-sample. In this task an animal sees one stimulus and then chooses between two or more alternatives, one of which is the same as the first;  the animal is then rewarded for choosing the matching stimulus.<ref name="Shettleworth" /><ref name="Wass" /><ref name="Zentall" />