Two lick suppression experiments using rats were conducted to determine whether extinction of a punctate excitor in a particular context would result in that context becoming a conditioned inhibitor, as defined by passing both summation and retardation tests. The role of extinction trial spacing was investigated as a possible determinant of whether the extinction context would become inhibitory. Experiment 1 demonstrated that, although inhibition was evident using either massed or spaced extinction trials, spaced trials reduced measurable inhibition as assessed by the summation test, but trial spacing had no influence on retardation test performance. Experiment 2 confirmed Experiment 1's conclusions while controlling for the influence of latent inhibition on the retardation test. In Experiment 2, the context proved inhibitory only following massed extinction trials. These data suggest that, at least with select parameters, an extinction context can become inhibitory.

To contrast the classic version of the Scalar Expectancy Theory (SET) with the Behavioral Economic Model (BEM), we examined the effects of trial frequency on human temporal judgments. Mathematical analysis showed that, in a temporal bisection task, SET predicts that participants should show almost exclusive preference for the response associated with the most frequent duration, whereas BEM predicts that, even though participants will be biased, they will still display temporal control. Participants learned to emit one response (R[S]) after a 1.0-s stimulus and another (R[L]) after a 1.5-s stimulus. Then the effects of varying the frequencies of the 1.0-s and 1.5-s stimuli were assessed. Results were more consistent with BEM than with SET. Overall, this research illustrates how the impact of non-temporal factors on temporal discrimination may help us to contrast associative models such as BEM with cognitive models such as SET. Deciding between these two classes of models has important implications regarding the relations between associative learning and timing.

Exposure to a cue alone either before (i.e., latent inhibition treatment) or after (i.e., extinction) the cue is paired with an unconditioned stimulus (US) results in attenuated conditioned responding to the cue. Here we report two experiments in which potential parallels between the context specificity of the effects of extinction and latent inhibition treatments were directly compared in a lick suppression preparation with rats. The reversed ordering of conditioning and nonreinforcement in extinction and latent inhibition designs allowed us to examine the effect of training order on the context specificity of what is learned given phasic reinforcement and nonreinforcement of a target cue. Experiment 1 found that when CS conditioning and CS nonreinforcement were administered in the same context, both extinction and latent inhibition treatments had reduced impact on test performance relative to excitatory conditioning when testing occurred outside the treatment context. Similarly, Experiment 2 found that when conditioning was administered in one context and nonreinforcement was administered in a second context, the effects of both extinction and latent inhibition treatments were attenuated when testing occurred in a neutral context relative to the context in which the CS was nonreinforced. The observed context specificity of extinction and latent inhibition treatments have both been previously reported, but not in a single experiment under otherwise identical conditions. The results of the two experiments convergently suggest that memory of nonreinforcement becomes context dependent after a cue is both reinforced and nonreinforced independent of the order of training.

This paper addresses sources contributing to the differences in the degree of recovery from extinction observed with different renewal paradigms. In two lick suppression experiments with rats, we assessed the role of the associative status of the acquisition context in both the weakness of AAC renewal and the sometimes observed weaker renewal resulting from an ABC design relative to an ABA design. In Experiment 1, we observed that AAC renewal relative to an AAA control group was small unless Context A had undergone associative deflation (i.e., extinction of Context A). Deflation of Context A not only decreased behavioral control by the CS in the AAA condition, but increased it in the AAC condition, thereby implicating a comparator process in addition to associative summation between the CS and test context. In Experiment 2, an excitatory acquisition context was found to enhance the difference between ABC and ABA renewal. Associative deflation of the acquisition context decreased ABA renewal more than ABC renewal. Thus, the associative value of the acquisition context (A) was more positively related to the level of renewal when the target CS (X) was tested in this context than when it was tested in a neutral but equally familiar context (C), consistent with the frequently observed greater renewal in an ABA condition than an ABC condition arising from associative summation of the CS and test context. These findings demonstrate that the excitatory status of the acquisition context influences the observed degree of renewal.

Like all biological systems, human memory is likely to have been influenced by evolutionary processes, and its abilities have been subjected to selective mechanisms. Consequently, human memory should be primed to better remember information relevant to one's evolutionary fitness. Supporting this view, participants asked to rate words based on their relevance to an imaginary survival situation better recall those words (even the words rated low in relevancy) than the same words rated with respect to non-survival situations. This mnemonic advantage is called the "survival-processing effect," and presumably it was selected for because it contributed to evolutionary fitness. The same reasoning suggests that there should be an advantage for recall of information that has been rated for relevancy to reproduction and/or mate seeking, although little evidence has existed to assess this proposition. We used an experimental design similar to that in the original survival-processing effect study (Nairne, Thompson, & Pandeirada, 2007) and across 3 experiments tested several newly designed scenarios to determine whether a reproduction-processing effect could be found in an ancestral environment, a modern mating environment, and an ancestral environment in which the emphasis was on raising offspring as opposed to finding a mate. Our results replicated the survival-processing effect but provided no evidence of a reproduction-processing effect when the scenario emphasized finding a mate. However, when rating items on their relevancy to raising one's offspring in an ancestral environment, a mnemonic advantage comparable to that of the survival-processing effect was found. (PsycINFO Database Record