Serial order of conditional stimuli as a discriminative cue for Pavlovian conditioning

Abstract

The serial order in which events occur can be a signal for different outcomes and therefore might be a determinant of how an animal should respond. In this report, we propose a novel design for studying serial order learning in Pavlovian conditioning. In both Experiments 1a and 1b, hungry rats were trained with successively presented pairs of auditory and visual stimuli (e.g., A --> B) using four different stimuli (A-D). Four orders were paired with food (A --> B, B --> C, C --> D, D --> A) while the reversals were extinguished (B --> A, C --> B, D --> C, A --> D). An analysis of responding from the second element of each pair showed that the rats discriminated trial types that preceded food from those that did not. A replication of the effect using a completely counterbalanced design is described in Experiment 1b. These results suggest that rats can use the serial or temporal order of two sequentially presented non-overlapping elements as the basis for discrimination. Two associative accounts are suggested as possible mechanisms for solving the discrimination.

SSCC TD: A Serial and Simultaneous Configural-Cue Compound Stimuli Representation for Temporal Difference Learning

“…In this type of procedure reinforced and non-reinforced configurations share the same set of elements, so that discrimination can only be attained on the basis of how the constituent elements are ordered. Murphy et al [46] presented a serial structural design that fully equated the levels of associative strength of each element and of each compound: that is, the net associative strength of the compounds was the same regardless of the order of the stimuli involved. Table 1 shows the design and parameters used in the simulation of their Experiment 1a.…”

“…Empirical (original measurement units) and simulated results during Murphy et al 's serial structural discrimination training (Experiment 1a) [46]. The top-left panel shows mean differential responses to the reinforced and non-reinforced trials across blocks of 3 sessions.…”

“…However, structural discriminations such as Murphy's et al [46], in which discriminative performance can only be achieved by encoding the specific order in which the stimuli are presented in each configuration, require both a configural cue representation and a real-time framework. Thus these tasks are insoluble using trial-based or simple summation associative mechanisms.…”

Rule Learning by Rats

“…Second, animals need to discriminate sequences paired with food from those that are not. Rats can learn twoelement sequences, A followed by B rather than B followed by A (12), as signals for food.…”

Targets for a Comparative Neurobiology of Language

“…The capacity of non-human animals to learn temporal patterns has been demonstrated in several species, including songbirds (Gentner et al, 2006; Abe and Watanabe, 2011), chimpanzees (Endress et al, 2010), rhesus macaques (Hauser and Glynn, 2009), cotton-top tamarins (Versace et al, 2008; Endress et al, 2009a), rats (Murphy et al, 2004), pigeons (Herbranson and Shimp, 2003, 2008), and human infants (Reber, 1969; Gomez and Gerken, 1999; Marcus et al, 1999, 2007). Although several of these studies examined (and showed strong evidence for) generalization to novel patterns following the learned rules, few have systematically explored whether animals are capable of generalizing the acquired patterns to sequences built from entirely novel elements.…”