Aparicio, C. F. (2001).
Overmatching in rats: The barrier choice paradigm.
Journal of the Experimental Analysis of Behavior,
75, 93-106.
The barrier choice paradigm was used to impose a cost on rats'
behavior of traveling between two levers: Pressing on two levers
was reinforced with food on concurrent random interval schedules,
but rats had to climb over a barrier to move from one lever to
another. The height of the barrier separating the levers was
increased from 30.5 to 45.7 cm across two phases that involved
various pairs of random interval schedules. With the 30.5-cm
barrier, the generalized matching law showed slopes equal to or
slightly above 1.0 for response and time allocation. With the
45.7-cm barrier, the generalized matching law showed slopes above
1.2 for responses, indicating that sensitivity to reinforcement
increased with increasing barrier height. For time allocation the
slopes remained close to 1.0; sensitivity to reinforcement did
not seem to increase with increasing barrier height. The role of
locomotion effort in choice situations is discussed.
Key words: overmatching, choice, barrier, locomotion, travel,
lever press, rats