Transswitching and contextual conditioning. Relevant aspects of time.

An empirical evaluation of temporal aspects of contextual conditioning was conducted in relation to Asratyan's (1965) theory of transswitching and to an alternative explanation that was partly stimulated by the Rescorla-Wagner model (Rescorla and Wagner 1972). On the basis of a human electrodermal conditioning preparation suggested by Kimmel and Ray (1978), five groups with 12 subjects each were run. The results indicated that the basic phenomena of transswitching are robust and therefore could be replicated; but the Asratyan theory was rejected. All the results supported an alternative explanation: in contextual conditioning, duration of contextual stimuli is less important than order. Phasic switching is due to simultaneous occurrence of stimuli (differential compound conditioning) and is therefore compatible with the Rescorla-Wagner model. Tonic switching is due to signals that occur before a marked sequence of conditioning trials, in part a challenge to the Rescorla-Wagner model. Long delays between critical events can perhaps be compensated for by mediating memory processes.