Meisch, R. A., & Spiga, R. (1998).
Matching under nonindependent variable-ratio schedules of drug reinforcement.
Journal of the Experimental Analysis of Behavior,
70, 23-34.
Response-contingent deliveries of oral pentobarbital maintained
responding of 3 rhesus monkeys during daily 3-hr sessions.
Deliveries of pentobarbital were arranged under nonindependent
concurrent variable-ratio variable-ratio schedules. Responses to
either schedule counted toward completion of both variable-ratio
schedule requirements. This schedule is similar in some respects
to conventional concurrent variable-interval variable-interval
schedules, in which passage of time counts toward completion of
the interval value on both schedules. Restricted nonindependent
concurrent variable-ratio variable-ratio schedules were also
studied. On that schedule, when a drug delivery was assigned to
one spout, it had to be collected before responses on the
opposite spout again counted toward completion of the schedule
requirements. Relative reinforcer magnitude was varied by
changing the drug concentration on one schedule while keeping the
drug concentration constant on the other variable-ratio schedule.
Under both types of concurrent variable-ratio variable-ratio
schedules, the relative rate of responding corresponded to the
relative drug intake. Unlike earlier studies of concurrent
variable-interval variable-interval intravenous cocaine
reinforcement, preference was proportionate to concentration, and
exclusive preferences did not develop. The relationship between
relative rate of responding and relative drug intake was well
described by the generalized matching law.
Key words: generalized matching law, reinforcement magnitude,
concurrent variable-ratio schedules, drug self-administration,
pentobarbital, spout-contact response, rhesus monkeys