Holm, L., Ladewig, J. 2007. The effect of housing rats in a stimulus rich versus stimulus poor environment on preference measured by sigmoid double demand curves. Applied Animal Behaviour Science 107(3-4), 342-354.

The present experiment investigated if the double demand curve method is sensitive to differences in housing conditions. We tested if rats performed more pressing when housed under barren compared to stimulating conditions, and if cross-points were ultimately affected. The experiment also aimed at inspecting the shape of double demand curves. Results indicate that housing conditions may exert some effect on both the amount of pressing performed and cross-points, but results on pressing and cross-points did not agree. In contrast to expectation, impoverished conditions did not cause rats to press more.