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Some critical factors of summation
in autoshaping. María F. Arias Holgado, Francisco Fernández-Serra and Luis E. Gómez-Sancho Universidad de Sevilla, Spain When two stimuli that have separately been paired with the same reinforcer are presented together, performance during the compound can be stronger than during its components. This additive summation effect has been demonstrated both in operant and classical conditioning studies, with a variety of procedures and species. That effect is in agreement with different theoretical approaches to stimulus control -namely, configural (e.g., Pearce et al., 1992), elemental (e.g., Hull, 1943; Rescorla y Wagner, 1972), and composite-stimulus control (Weiss, 1972) theories. Surprisingly, however, as far as classical and operant conditioning with pigeons are concerned successful demonstrations are very scarce. In fact, there is only one study reporting additive summation in autoshaping with pigeons (Pearce et al., 1999). It has been suggested that autoshaping does not provide a sensitive measure of control by elements of the compound. In order to clarify some of critical factors involved in summation of autoshaped responses we report additional data about the role of background stimuli (presence versus absence) on performance in summation tests. We also consider the frequency of reinforcement effect and the way that summation tests are conducted on the rate of response to compound stimulus. Keywords: summation, autoshaping, pigeons |
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