Anderson Karen G, Velkey Andrew J, Woolverton William L
Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N State Street, Jackson, MS 39216-4505, USA.
Psychopharmacology (Berl). 2002 Oct;163(3-4):319-26. doi: 10.1007/s00213-002-1012-7. Epub 2002 Mar 1.
The generalized matching law predicts that the relative rate of behavior maintained by different reinforcers will match the relative rate of reinforcement. It has previously been shown that responding maintained by either food deliveries or cocaine injections under concurrent variable-interval (conc VI) schedules is well described by the generalized matching law. However, the generality of this conclusion to the choice between a drug and a non-drug reinforcer has not been well established.
The objective of the present study was to determine the extent to which the generalized matching law could account for choice between cocaine and food.
Four male rhesus monkeys (Macaca mulatta) lever pressed under various pairs of conc VI schedules with food and/or cocaine injection as the maintaining events. Two doses of cocaine (0.025 and 0.05 mg/kg per injection) were selected to provide information about reinforcer magnitude.
As has been found in a context of choice between identical reinforcers, the generalized matching law accounted for most behavior. As in earlier studies with identical reinforcers, there was less responding apportioned to the alternative with the greater reinforcement frequency than predicted by the generalized matching law, i.e., undermatching was observed frequently. There was a tendency for more responding to be emitted toward the food alternative when the lower dose of cocaine was available and toward the drug alternative when the higher dose of cocaine was available.
These results suggest that, as proposed by the generalized matching law, relative reinforcement rate is an important determinant of choice between a drug and a non-drug reinforcer.
广义匹配法则预测，由不同强化物维持的行为相对速率将与强化相对速率相匹配。此前已有研究表明，在并发可变间隔（conc VI）日程安排下，由食物投放或可卡因注射维持的反应能很好地用广义匹配法则来描述。然而，这一结论对于药物与非药物强化物之间选择的普遍性尚未得到充分证实。
本研究的目的是确定广义匹配法则在多大程度上能够解释在可卡因和食物之间的选择。
四只雄性恒河猴（猕猴）在各种成对的conc VI日程安排下按压杠杆，以食物和/或可卡因注射作为维持事件。选择了两种剂量的可卡因（每次注射0.025和0.05毫克/千克）以提供关于强化物大小的信息。
正如在相同强化物之间的选择情境中所发现的那样，广义匹配法则解释了大部分行为。与早期关于相同强化物的研究一样，分配给强化频率更高的选项的反应比广义匹配法则预测的要少，即经常观察到不匹配现象。当有较低剂量的可卡因时，对食物选项的反应倾向于更多；当有较高剂量的可卡因时，对药物选项的反应倾向于更多。
这些结果表明，正如广义匹配法则所提出的，相对强化率是药物与非药物强化物之间选择的一个重要决定因素。
