Animal Learning & Behavior

, Volume 7, Issue 4, pp 417–423 | Cite as

Classical conditioning in paramecia

  • Todd M. Hennessey
  • William B. Rucker
  • Colin G. McDiarmid


SingleParamecium caudatum were conditioned by pairing ac-generated electric shock (US) with a vibratory stimulus (CS) produced by an auditory speaker. Naive paramecia subjected to shock reliably exhibited a backwards jerk and axial spinning similar to the avoiding reaction described by Jennings in 1904. Such responses did not occur initially to CS alone, but increasingly appeared during the CS period preceding shock pairing (delayed conditioning paradigm). Control subjects given the CS and UCS at the same intervals, but explicitly unpaired, did not show a sustained increase of responses to the CS alone. Short-term memory was demonstrated by subjects first conditioned and then presented CS alone during extinction. These subjects were readily reconditioned. Paramecia trained and stored for 24 h showed reliable memory savings as compared to stored control subjects. Other paramecia were differentially conditioned by training with two CSs. Following the recommendations of Rescorla (1967), a procedure was designed for truly random presentation of the CS and UCS as an additional control for pseudoconditioning. Single paramecia were conditioned with intervals between CSs randomly ranging from 8 to 32 sec. Control subjects received the same number of CSs and UCSs, which were administered independently and randomly during the same total session duration. Thus, CS and UCS were occasionally paired for control subjects. The responses to CS in the conditioned group were anticipatory conditional responses due to the pairing contingency and not wholly due to pseudoconditioning.


Conditioned Response Classical Conditioning Paired Stimulus Vibratory Stimulus Escape Training 
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Reference Note

  1. Hennessey, T. M., Cullen, C, & Rucker, W. B. (with media assistance from E. Lamont).Video review of classical conditioning procedures for paramecia. Videotape presented at the 2nd Annual Meeting of the Midwestern Association of Behavioral Analysis, Chicago, May 1976. The tape is available on loan from W. B. Rucker, Department of Psychology, Mankato State University, Mankato, Minnesota 56001.Google Scholar


  1. Benson, D. J., Rucker, W. B., & McDiarmid, C. G. Possible instrumental avoidance in Paramecium.Program and Abstracts of the Society for Neuroscience Fourth Annual Meeting, 1974, 137(b). (Abstract)Google Scholar
  2. Bullington, W. E. A further study of spiraling in the ciliateParamecium with a note on morphology and taxonomy.Journal of Experimental Zoology, 1938,56, 423–449.CrossRefGoogle Scholar
  3. Corning, W. C., &von Burg, R. Protozoan learning. In W. C. Corning, J. A. Dyal, & A. O. D. Willows (Eds.),Invertebrate learning (Vol. 1). New York: Plenum, 1973.Google Scholar
  4. Durkovic, R. G. Classical conditioning, sensitization, and habituation in the spinal cat.Physiology & Behavior, 1975,14, 297–304.CrossRefGoogle Scholar
  5. Eisenstein, E. M. (Ed.),Aneural organisms in neurobiology, New York: Plenum, 1975.Google Scholar
  6. French, J. W. Trial- and-error learning inParamecium.Journal of Experimental Psychology, 1940,26, 609–613.CrossRefGoogle Scholar
  7. Halstead, W. C., &Rucker, W. B. Memory: A molecular maze.Psychology Today, June 1968,2, pp. 38–41; 66–67.Google Scholar
  8. Hanzel, T. E., &Rucker, W. B. Escape training in paramecia.Journal of Biological Psychology, 1971 (Dec),13, 24–28.Google Scholar
  9. Hanzel, T. E., &Rucker, W. B. Trial and error learning in Paramecium: A replication.Behavioral Biology, 1972,7, 873–880.CrossRefPubMedGoogle Scholar
  10. Hildebrand, E., &Dryl, S. Significance of Ca++ and K+ ions for excitation of protozoan membrane.Bioelectrochemistry and Bioenergetics, 1976,3, 543–544.CrossRefGoogle Scholar
  11. Huber, J. C. Speculations concerning the physiology of learning in paramecia.Journal of Biological Psychology, 1972,14(2), 22–29.Google Scholar
  12. Huber, J. C., Rucker, W. B., &McDiarmid, C. G. Retention of escape training and activity changes in single paramecia.Journal of Comparative and Physiological Psychology, 1974,86, 258–266.CrossRefGoogle Scholar
  13. Jennings, H. S. The behavior ofParamecium. Additional features and general relations.Journal of Comparative Neurology, 1904,14, 441–510.CrossRefGoogle Scholar
  14. Jensen, D. D. Paramecia, planaria, and pseudo-learning.Animal Behaviour, 1965,13(Supplement 1), 9–20.Google Scholar
  15. Kimble, G. A. Hilgard and Marquis’ conditioning and learning (2nd ed.). New York: Appleton-Century-Crofts, 1961.Google Scholar
  16. Lee, R. M. Conditioning inPleurobranchea.Science, 1976,193, 72–73.CrossRefPubMedGoogle Scholar
  17. Machemer, H. Interactions of membrane-potential and cations in regulation of ciliary activity inParamecium.Journal of Experimental Biology, 1976,65, 427–447.PubMedGoogle Scholar
  18. Naitoh, Y., &Eckert, R. Ionic mechanisms controlling behavioral responses ofParamecium to mechanical stimulation.Science, 1969,164, 963–965.CrossRefPubMedGoogle Scholar
  19. McConnell, J. V. Comparative physiology: Learning in invertebrates.Annual Review of Physiology, 1966,74, 18–20.Google Scholar
  20. Miller, N. E. Certain facts of learning relevant to the search for its physical basis. In Quarton, G. C., Melnechuk, T., & Schmitt, F. O. (Ed.),The neurosciences, a study program. New York: Rockefeller University Press, 1967.Google Scholar
  21. Mpitsos, G. J. Conditioning inPleurobranchea.Science, 1976,193, 73–74.Google Scholar
  22. Nelson, D. L., &Kung, C. Behavior of Paramecium—Chemical, physiological and genetic studies. In G. L. Hazelbauer,Taxis and behavior. London: Chapman and Hall, 1978.Google Scholar
  23. Patterson, M. M., Cegavske, C. F., &Thompson, R. F. Effects of a classical conditioning paradigm on hind-limb flexor nerve response in immobilized spinal cats.Journal of Comparative and Physiological Psychology, 1973,84, 88–97.CrossRefPubMedGoogle Scholar
  24. Poskocil, A. If you’re a Paramecium, can you learn? A query.Worm Runner’s Digest, 1966,8, 31–42.Google Scholar
  25. Rescorla, R. A. Pavlovian conditioning and its proper control procedures.Psychological Review, 1967,74, 71–80.CrossRefPubMedGoogle Scholar
  26. Rucker, W. B., & Huber, J. C. Stimulus specificity of habituation to vibratory stimulus inSpirostomum. Program and Abstracts of the Society of Neuroscience Third Annual Meeting, 1973, 378. (Abstract)Google Scholar
  27. Thorpe, W. H. Learning and instinct in animals (2nd ed.). Cambridge: Harvard University Press, 1968.Google Scholar

Copyright information

© Psychonomic Society, Inc. 1979

Authors and Affiliations

  • Todd M. Hennessey
    • 1
  • William B. Rucker
    • 1
  • Colin G. McDiarmid
    • 1
  1. 1.Department of PsychologyMankato State UniversityMankato

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