Consumer demand tests (animals)

[4] Costs of resources can be imposed on animals by an operant task (e.g. lever-pressing), a natural aversion (e.g. crossing water), or a homeostatic challenge (e.g. increased body temperature).

Furthermore, argument by analogy indicates that as with humans, it is more likely that animals will experience negative affective states (e.g. frustration, anxiety) if they are not provided with the resources for which they show high motivation.

The rate (i.e. regression line) at which the animal decreases its acquisition or consumption of a resource as the cost increases is known as the elasticity of demand.

[12] Savory and Duncan showed that individual hens kept in a background of darkness were prepared to work for 4 hours of light per day.

[19] Duncan and Kite showed that hens were highly motivated to gain access to a nest box, particularly immediately prior to oviposition.

The hens would push a weighted door, or walk through water or an air blast to reach a nest box.