Paul Skjoldager, Gail Winger, James H. Woods

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Behavior maintained by intravenously delivered alfentanil, cocaine, or ketamine was assessed using a fixed‐ratio schedule of reinforcement. As the dose of each drug was increased, rate of responding also increased up to a maximum. Further increases in dose resulted in decreased response rates (inverted U‐shaped curve). An analysis of postreinforcement‐pause‐time and run‐time measures for the ascending limb of the inverted U‐shaped functions revealed that behavior was characterized by systematic decreases in both pause time and run time as dose and rate increased. An examination of the descending limb of the dose‐response functions revealed that lowered response rates for cocaine and ketamine were correlated with increases in run time and small and inconsistent effects on postreinforcement pause time. Behavior maintained by rate‐reducing doses of alfentanil was characterized by lengthened postreinforcement pauses with small increases in run time. These data suggest that at larger doses, drug reinforcers may have unconditioned or direct effects on the behavior that the drug is maintaining, and more important, that the nature of these unconditioned effects depends on the drug that is maintaining behavior. 1991 Society for the Experimental Analysis of Behavior

Original languageEnglish (US)
Pages (from-to)331-343
Number of pages13
JournalJournal of the experimental analysis of behavior
Issue number2
StatePublished - Sep 1991
Externally publishedYes


  • alfentanil
  • cocaine
  • fixed‐ratio schedule
  • ketamine
  • lever press
  • postreinforcement pause
  • rhesus monkeys
  • run time
  • self‐administration

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Behavioral Neuroscience


Dive into the research topics of 'ANALYSIS OF FIXED‐RATIO BEHAVIOR MAINTAINED BY DRUG REINFORCERS'. Together they form a unique fingerprint.

Cite this