Evidence for an association between the discriminative stimulus and the response-outcome association in instrumental learning

In 4 experiments, rats received 1 of several outcomes for engaging in various instrumental responses in the presence of discriminative stimuli. Discriminative stimuli shared some response-outcome relations but not others. When a response was subsequently extinguished in the presence of 1 discriminative stimulus, that produced relatively more decrement in responding in other stimuli that shared the same response-outcome relation. Other discriminative stimuli, in the presence of which that response had been reinforced by other outcomes and in which the original outcome had reinforced another response, were less affected. Moreover, postextinction devaluation of that outcome suggested that the particular response-outcome relation extinguished had undergone decrement. These results suggest that discriminative stimuli have relatively specific associations with the response-outcome relations that obtain in their presence.     

The extinction of within-compound flavor associations

Three experiments studied extinction of the associations which are formed between two flavors presented in a simultaneous compound. In Experiment 1 those associations were identified by a sensory preconditioning procedure in which the poisoning of one element of the compound led to the rejection of the other element. Separate presentation of either element between their joint occurence and the poisoning of one element sharply attenuated the rejection of the other element. That attenuation was interpreted in terms of the extinction of within-compound associations. Experiment 2 obtained similar results with an alternative extinction procedure in which the elements of the original compound were presented in other compounds. Experiment 3 obtained similar results when the existence of the within-compound associations was determined by an alternative assessment procedure in which one element of the compound was made more attractive by the induction of a specific hunger. These experiments suggest that within-compound associations can be extinguished when the elements are separately presented outside of the compound. Experiments 2 and 3 make less plausible an alternative interpretation of the effects of separate element presentation in terms of reduction of the novelty of the element. The findings may be taken as implying that the elements of a simultaneously presented compound are joined by a single symmetrical association which acts at various points during a sensory preconditioning experiment.     

Stimulus generalization: some predictions from a model of Pavlovian conditioning.

Three experiments examined predictions generated by incorporating a common-elements account of stimulus generalization within the Rescorla-Wagner model of conditioning. All experiments employed rats in a conditioned suppression situation. Experiments 1 and 2 found that conditioning of a similar stimulus augmented the excitation controlled by a near-asymptotic target stimulus more than did further conditioning of the target itself. Prior discrimination training between the target and the similar stimulus enlarged this effect, compared with prior discrimination between the target and another dissimilar stimulus. Nonreinforced exposure of the similar stimulus prior to its reinforcement also increased the effect. Experiment 3 examined a related prediction for inhibition. After discrimination training, extinction of the previously reinforced stimulus revealed more inhibition to the previously nonreinforced stimulus when those two stimuli were more similar. These outcomes are consistent with deductions from the present model and encourage further testing of its expansion to the case of stimulus generalization.     

Epistemic and Dialectical Regress

Dialectical egalitarianism holds that every asserted proposition requires defence when challenged by an interlocutor. This view apparently generates a vicious ‘regress of justifications’, since an interlocutor can challenge the premises through which a speaker defends her original assertion, and so on ad infinitum. To halt the regress, dialectical foundationalists such as Adler, Brandom, Leite, and Williams propose that some propositions require no defence in the light of mere requests for justification. I argue that the putative regress is not worrisome and that egalitarianism can handle it quite satisfactorily. I also defend a positive view that combines an anti-foundationalist conception of dialectical interaction with a foundationalist conception of epistemic justification.     

The effect of change in US quality on the blocking effect

If one CS is paired with a US and then that CS together with a “redundant” stimulus is paired with the US, conditioning of that “redundant” stimulus is attenuated or blocked. The present experiment explores the effect upon this blocking of changing the quality of the US coincident with the introduction of the redundant stimulus. Changing US quality disrupted blocking only when the US potency was also increased. Quality changes in which the redundant stimulus was correlated with a lower potency US only increased blocking. These results are taken as supporting the conditioning model of Rescorla and Wagner but inconsistent with a casual informational model of conditioning.     

Collateral Reports and Cross-Informant Agreement about Adult Psychopathology in 14 Societies

To advance international mental health assessment, instruments that have been internationally validated are needed. To this end, we analyzed ratings from 14 societies on the Adult Behavior Checklist (ABCL), a collateral-report form parallel to the Adult Self-Report (ASR; Achenbach and Rescorla 2003) for ages 18 to 59. Both the ABCL and the ASR assess problems, personal strengths, and adaptive functioning. For a sample of 8322 see note below collaterals, we found strong consistency across societies regarding which ABCL problem items tended to obtain relatively low, medium, or high ratings. Most societal effect sizes (ESs) for problem scale scores were small to medium (< 13.9 %), but the ES for the ABCL Personal Strengths scale was 25 %. For most of the same participants (N = 8,302), we analyzed cross-informant agreement between self-reports on the ASR and collateral reports on the ABCL. Cross-informant correlations for problem scale scores averaged .47, with considerable societal variation. Problem score means were higher on the ASR than the ABCL in every society, but the size of the difference varied across societies. Mean item ratings on the ABCL and ASR were highly correlated within every society (mean r = .92), but within-dyad item rating agreement varied widely in every society (mean r = .39). In all societies, non-corroboration of self-reported deviance and of collateral-reported deviance was common. Overall findings indicated considerable similarity but also some important differences in collateral-reported problems and adaptive functioning across 14 societies.