A new approach to study preference: Applying Hernstein’s matching law in a two bottles paradigm

C. Sanchis-Segura1, R. Spanagel1, F.A. Hehn2 and B. Vollmayr2

1Department of Psychopharmacology, CIMH, Mannheim. Germany
2Biochemical laboratory, CIMH, Mannheim, Germany

In preclinical research, as they cannot be directly assessed, hedonic properties of a stimulus are usually inferred by analyzing its preference over another ‘control’ stimulus (i.e. water). Here we present a method to obtain a more sophisticated index of preference. This procedure is very similar to other two-bottles based sucrose preference tests. Thus, this method also consist in an evaluation of the preference of different sucrose concentrations over water but it also includes subtle comparisons among different sucrose concentrations simultaneously available for a restricted time (in our case, 1 hour). These discrete preference comparisons are then used to estimate a general pattern in the preference allocation and its correspondence towards the relative magnitude of the reinforcement sources available. This is accomplished by applying the generalized matching law equation and basically consists on the estimation of the regression line relating changes in preference according to changes in the ratio of two reward sizes simultaneously available. This test has some advantages over traditional methods:

  1. It does not require deprivation.
  2. It is more sensitive.
  3. It is obtained across a wide range of conditions.
  4. It provides a function describing the dynamic relationship between reinforcer magnitude changes and individual’s behavioral allocation of preference.     

Paper presented at Measuring Behavior 2005 , 5th International Conference on Methods and Techniques in Behavioral Research, 30 August - 2 September 2005, Wageningen, The Netherlands.

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