Compulsory Regime and Control of Environment in Animal Behavior I. Wheel-Running

1. An enclosure is described which provides scope for the study of many aspects of wheel-running by small mammals. The condition of the wheel can be controlled by the experimental subjects through the pressing of microswitch levers. Alternative states of the wheel include free-wheeling, locked and motor-driven (in either direction at various speeds). 2. Equipment is described for digital and/or analog recording of time of running and revolutions per unit time, speed and direction of running, and for split-second printout of correlations. 3. Deer mice, Peromyscus crinitus, are found to have characteristic patterns of spontaneous free-wheeling running activity, from the points of view of temporal distribution, sustained speed and direction. These patterns tend to be maintained on free-wheeling and motor-driven running schedules requiring prior and repeated instrumental acts. The animals sometimes go through a "warm-up" phase before attaining and sustaining their customary running speed. 4. Deer mice repeatedly press levers that convert a locked wheel to free-wheeling, in which condition it can be run for a preset time. They also engage in volitional motor-driven running, i.e., running of a motor-driven wheel which they start and stop by pressing levers. However, they do not accept non-self initiated motor-driven running. As often as rotation of the wheel is started by an outside agency, they promptly press a lever which stops it. Conversely, the animals also tend to restart the rotation of a motor-driven wheel promptly after it is halted by an outside agency. 5. Variable results were obtained when volitional motor-driven running was permitted concurrently with the scheduling of forced motor-driven running. One animal's volitional motor-driven running was not affected by the fact that rotation of the wheel was initiated automatically (but promptly stopped by it) every half-hour. The other animal eventually ceased all volitional motor-driven running on this program. When returned to a program of purely volitional motor-driven running, the former animal's running increased and the latter animal "enthusiastically" resumed running. 6. In the light of these results and parallel findings in current studies on control of illumination by deer mice, several suggestions can be made concerning the behavior of small mammals in confinement. a) Deer mice tend to react to the arbitrary imposition of regime by opposition to it. Thus, if animals have the power to counteract the effects of initiation or cessation of environmental modifications, they may promptly do so. b) Greatly restricting the alternatives for action (which are open to deer mice in the wild) by confinement in relatively barren enclosures, influences subsequent behavior. Thus, confined animals given control over environmental modifications may repeatedly exercise this control. These animals find it rewarding to attain and to exercise a degree of control over the environment, perhaps in partial substitution for the control exerted in the wild (but withdrawn by confinement), perhaps in any circumstances. c) Taken alone, the nature of a specific stimulus (or activity) is an unreliable guide for interpreting the behavior of small mammals upon whom it is forced or to whom it is presented unexpectedly, or for interpreting the behavior of confined animals given control over its initiation and/or cessation (except when relatively great stress is involved). Stimuli which are rewarding (or punishing) in certain circumstances can become punishing (or rewarding) in other circumstances. 7. Certain findings on the effects of shock on learning, and on self and non-self electrical stimulation of the hypothalamus, that have previously been regarded as enigmatic, are discussed. It is suggested that the observed behavior can be understood better when the effects of compulsory regime and control of environment are taken into account.