It's the information!

Abstract

Learning in conditioning protocols has long been thought to depend on temporal contiguity between the conditioned stimulus and the unconditioned stimulus. This conceptualization has led to a preponderance of associative models of conditioning. We suggest that trial-based associative models that posit contiguity as the primary principle underlying learning are flawed, and provide a brief review of an alternative, information theoretic approach to conditioning. The information that a CS conveys about the timing of the next US can be derived from the temporal parameters of a conditioning protocol. According to this view, a CS will support conditioned responding if, and only if, it reduces uncertainty about the timing of the next US.

Figure 1

Acquisition speed as a function of trial CS duration. Different groups of pigeons were exposed to an autoshaping protocol with fixed delays that ranged from 4 s to 32 s. For some groups, the duration of the intertrial interval was kept constant (filled circles). For these groups, the number of trials to acquisition increased with increased CS duration. In other groups (filled squares) the ratio of the intertrial to trial CS duration was kept constant. In these groups, speed of acquisition remained constant regardless of the duration of the trial CS. After Balsam et al. (2010). Original data from Gibbon et al., (1977).

Figure 2

CS informativeness as a function of trial CS duration. Bits of information per CS presentation across the different groups displayed in Figure 1. Bits of information was calculated according to Equation 2. For groups in which the duration of the intertrial interval was constant (filled circles), bits of information conveyed by each CS presentation decrease as the duration of the trial CS increases. For groups in which the ratio of the intertrial interval to trial CS duration was kept constant (filled squares), bits of information conveyed by each CS presentation remains constant across increasing CS duration.