Associative structure of second-order conditioning in humans

Abstract

Second-order conditioning (SOC; i.e., conditioned responding to S2 as a result of S1-US pairings followed by S2-S1 pairings) is generally explained by either a direct S2→US association or by an associative chain (i.e., S2→S1→US). Previous research found that differences in responses to S2 after S1 was extinguished often depended on the nature of the S2-S1 pairings (i.e., sequential or simultaneous). In two experiments with human participants, we examined the possibility that such differences result from S1 evoking S2 during extinction of S1 following simultaneous but not sequential S2-S1 pairings. This evocation of S2 by S1 following simultaneous pairings may have paired the evoked representation of S2 with absence of the outcome, thereby facilitating mediated extinction of S2. Using sequential S2-S1 pairings, both Experiments 1 and 2 failed to support this account of how extinction of S1 reduced responding to S2. Experiment 1 found that extinguishing S1 reduced responding to S2, while extinguishing S2 had little effect on responses to S1, although forward evocation of S1 during extinction of S2 paired the evoked representation of S1 with absence of the outcome. In Experiment 2, evocation of S2 during S1 nonreinforced trials was prevented because S2-S1 pairings followed (rather than proceeded) S1-alone exposures. Nevertheless, responding to S2 at test mimicked S1 responding. Responding to S2 was high in the context in which S1 had been reinforced and low in the context in which S1 had been nonreinforced. Collectively, these experiments provide additional support for the associative-chain account of SOC.

Second-Order Conditioning in Humans

“…Jara et al (2006) concluded that SOC was best described by an independent (direct link between CS2-US) rather than a chained (CS2-CS1-US) causal structure, but noted that their results might also be consistent with the S-R view if it was assumed that the causal judgment itself was the conditioned response. Craddock et al (2018) found the opposite result-attenuation of SOC following extinction of CS1 when the CS2-CS1 compound was presented serially, supporting the associative chain-view. It should be noted the dependent variable in this study was slightly unusual, involving a single transformed score combining participants' binary predictions of the outcome and their normalized reaction times [see Craddock et al (2012)].…”

“… Craddock et al (2018) found the opposite result–attenuation of SOC following extinction of CS1 when the CS2-CS1 compound was presented serially, supporting the associative chain-view. It should be noted the dependent variable in this study was slightly unusual, involving a single transformed score combining participants’ binary predictions of the outcome and their normalized reaction times [see Craddock et al (2012) ].…”

“…Lee and Livesey (2012) found that when cue X was combined with a transfer excitor (B +) in a novel compound (BX), participants gave higher predictive ratings at test compared to when the same transfer excitor was combined with a non-causal control cue trained alone (C-) or in compound (DE-). Craddock et al (2018) also demonstrated SOC in a predictive learning scenario with serial (as opposed to simultaneous) presentation of the compound trials (i.e., CS2 → CS1) where participants made predictions about the occurrence of an outcome (the text "WIN" presented on screen).…”

“…The authors reported that successful simulation of the empirical results depended on the covered light being encoded as “undefined” in the auto-associator, rather than “off” (which resulted in inhibition after a brief excitatory period). Finally, Craddock et al (2018) specifically instructed participants to learn the associations between the first- and second-order stimuli, and participants were not asked to make predictions about the outcome during the CS2-CS1 pairings.…”

Time in Associative Learning: A Review on Temporal Maps

“…Several studies followed up to investigate the structural properties of temporal maps (Arcediano et al, 2005;Polack et al, 2013;Craddock et al, 2018). Arcediano et al (2005) examined the directional nature of temporal maps in humans (experiment 1) and non-humans (experiment 2A-2C).…”