Behavioural demand functions of caged laboratory mice for additional space (1997)

Sherwin, C. M., Nicol, C. J.

Abstract

Mice demonstrate a strong motivation to gain access to space additional to that provided by a standard laboratory cage, even when this provides no further resources or enrichment. The importance of a commodity, as perceived by animals, can be determined by measuring the amount of work animals are prepared to perform to gain access to that commodity. In the present study, this method is extended to establish how animals perceive the importance of increasing amounts of one commodity, that is, additional space. ...The amount of access gained decreased as the work required increased, but the slope of the function (-0.347) was sufficiently shallow to indicate that additional space was regarded by the mice as a highly important commodity. .. The absence of large differences in response to disparate sizes of additional space may indicate that the mice may have (1) been motivated to escape their home-cage, (2) been motivated to search for unavailable resources, or (3) perceive the different amounts of additional space as nearly equally (non-)rewarding.