Food carrying: a new method for naturalistic studies of spontaneous and forced alternation.

Spontaneous alternation has been studied in laboratory tests given to rodents since 1935. Herein is described a simple new technique that allows the animal to perform without intertrial handling. The apparatus has a centered covered 'home base' and two relatively exposed arms. When presented with large food pellets, the rats carry them from the exposed arms to the home base before consuming them. The utility of the method is demonstrated in four exemplar paradigms ranging from two choice tasks to food 'hoarding' and exploratory tasks. The procedure can be modified for forced and other alternation paradigms and allows collection of a variety of psychophysical measures. The strength of the task is that it provides an analogue of natural foraging behavior.