The Significance of Exogenous and Endogenous Factors in the Hereditary Differences in Learning Ability of Rats

  • H. Müller-Calgan
  • E. Schorscher


Rats from the strain Wistar/WU/Ivanovas were trained to jump over a hurdle to avoid an electric shock. Learning experiments performed on rats selected for good (GL) and bad (BL) learning, (plus unselected control groups), yielded the following results:
  1. 1.

    F7 – F14 BL no longer react to the selection bias and the corresponding GL react only very feebly.

  2. 2.

    In comparison with the F1 and F2 generations of GL and BL the variability decreases. The animals become less sensitive to exogenous factors.

  3. 3.

    Details are given on exogenous (and endogenous) factors with or without influence on the learning results.



Avoidance Conditioning Avoidance Training Relative Frequency Distribution Ditioned Stimulus Cage Population 


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Copyright information

© Plenum Press, New York 1973

Authors and Affiliations

  • H. Müller-Calgan
    • 1
  • E. Schorscher
    • 1
  1. 1.Department of Pharmacology Medical Research DivisionE. MerckDarmstadtW. Germany

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