112 research outputs found

    Drug cue reactivity involves hierarchical instrumental learning: evidence from a biconditional Pavlovian to instrumental transfer task

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    This is the final version of the article. Available from Springer Verlag via the DOI in this record.RATIONALE: Drug cue reactivity plays a crucial role in addiction, yet the underlying mechanisms are poorly understood. According to the binary associative account, drug stimuli retrieve an expectation of the drug outcome, which, in turn, elicits the associated drug-seeking response (S-O-R). By contrast, according to the hierarchical account, drug stimuli retrieve an expectation that the contingency between the drug-seeking response and the drug outcome is currently more effective, promoting performance of the drug-seeking response (S:R-O). METHODS: The current study discriminated between these two accounts using a biconditional Pavlovian-to-instrumental transfer (PIT) task with 128 alcohol drinkers. A biconditional discrimination was first trained in which two responses produced alcohol and food outcomes, respectively, and these response-outcome contingencies were reversed across two discriminative stimuli (SDs). In the PIT test, alcohol and food cues were compounded with the two SDs to examine their impact on percent alcohol choice in extinction. RESULTS: It was found that alcohol and food cues selectively primed choice of the response that earned that outcome in each SD (p < .001), and this effect was associated with participants' belief that cues signalled greater effectiveness of that response (p < .0001). CONCLUSIONS: The alcohol stimulus could not have selectively primed the alcohol-seeking response through binary S-O-R associations because the drug outcome was equally associated with both responses. Rather, the alcohol stimulus must have retrieved an expectation that the response-alcohol contingency available in the current context was more likely to be effective (S:R-O), which primed performance of the alcohol-seeking response.The work was supported by an ESRC PhD scholarship to Lorna Hardy

    Evidence of a Goal-Directed Process in Human Pavlovian-Instrumental Transfer

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    © 2017 APA, all rights reserved). Cues that signal rewards can motivate reward-seeking behaviors, even for outcomes that are not currently desired. Three experiments examined this phenomenon, using an outcome-selective Pavlovian-instrumental transfer (PIT) design and an outcome devaluation procedure. In Experiment 1, participants learned to perform one response to earn crisps points and another response to earn popcorn points. One outcome was then devalued by adulterating it to make it taste unpleasant. On test, overall response choice was biased toward the outcome that had not been devalued, indicating goal-directed control. Stimuli that signaled crisps and popcorn also biased instrumental response choice toward their respective outcomes (a PIT effect). Most importantly, the strength of this bias was not influenced by the devaluation manipulation. In contrast, Experiment 2 demonstrated that when stimuli signaled equal probability of the two outcomes, cue-elicited response choice was sensitive to the devaluation manipulation. Experiment 3 confirmed this conclusion by demonstrating a selective avoidance of the cued, devalued outcome. Together, these data support a goal-directed model of PIT in which expected outcome probability and value make independent contributions to response choice. (PsycINFO Database Recor

    Auditing with accountability : shrinking the opportunity spaces for audit failure

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    In recent years a number of high-profile company failures have raised fundamental questions about the willingness and/or ability of auditors to exercise the professional scepticism necessary for the production of robust audits. This report, co-written by Adam Leaver at the University of Sheffield and Leonard Seabrooke, Saila Stausholm and Duncan Wigan at Copenhagen Business School, examines the causes of those failures and makes a series of recommendations on how to resolve them. The report argues that audit failure takes place within a particular configuration of economic, cultural and regulatory arrangements which create the 'opportunity spaces' for poor practice. Shrinking those opportunity spaces therefore requires a multi-dimensional response, including the structural separation of audit and non-audit functions, a more robust system of fines and the integration of a civil society voice into the reform process to prevent regulatory capture

    The propositional basis of cue-controlled reward seeking

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    peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=pqje2

    Automaticity and cognitive control: Effects of cognitive load on cue-controlled reward choice

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    This is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this recordThe extent to which human outcome-response (O-R) priming effects are automatic or under cognitive control is currently unclear. Two experiments tested the effect of cognitive load on O-R priming to shed further light on the debate. In Experiment 1, two instrumental responses earned beer and chocolate points in an instrumental training phase. Instrumental response choice was then tested in the presence of beer, chocolate, and neutral stimuli. On test, a Reversal instruction group was told that the stimuli signalled which response would not be rewarded. The transfer test was also conducted under either minimal (No Load) or considerable (Load) cognitive load. The Non-Reversal groups showed O-R priming effects, where the reward cues increased the instrumental responses that had previously produced those outcomes, relative to the neutral stimulus. This effect was observed even under cognitive load. The Reversal No Load group demonstrated a reversed effect, where response choice was biased towards the response that was most likely to be rewarded according to the instruction. Most importantly, response choice was at chance in the Reversal Load condition. In Experiment 2, cognitive load abolished the sensitivity to outcome devaluation that was otherwise seen when multiple outcomes and responses were cued on test. Collectively, the results demonstrate that complex O-R priming effects are sensitive to cognitive load, whereas the very simple, standard O-R priming effect is more robust

    Goal-directed control in Pavlovian-instrumental transfer

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    The current article concerns human outcome - selective Pavlovian - instrumental transfer (PIT), where Pavlovian cues selectively invigorate instrumental responses that predict common rewarding outcomes. Several recent experiments have observed PIT effects that were insensitive to outcome devaluation manipulations, which has been taken as evidence of an automatic “associative” mechanism. Other similar studies observed PIT effects that were sensitive to devaluation, which suggest s a more controlled, goal - directed process. Studies supporting the automatic approach have been criticised for using a biased baseline, while studies supporting the goal - directed approach have been criticised for priming multiple outcomes attest. The current experiment addressed both of these issues. Participants first learned to perform two instrumental responses to earn two outcomes each (R1 - O1/ O3, R2 - O2/ O4), before four Pavlovian stimuli (S1 - S4) were trained to predict each outcome. One outcome that was paired with each instrumental response (O3 and O4) was then devalued, so that baseline response choice at test would be balanced. Instrumental responding was then assessed in the presence of each individual Pavlovian stimulus, so that only one outcome was primed per trial. PIT effect s were observed for the valued outcomes , t s > 3.99, p s < .001, but not for the devalued outcomes , F < 1 , BF 10 = 0.29. Hence, when baseline response choice was equated and only one outcome was primed per test trial, PIT was sensitive to outcome devaluation. The data therefore support goal - directed models of PIT

    The Antarctic Slope Current in a Changing Climate

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    The Antarctic Slope Current (ASC) is a coherent circulation feature that rings the Antarctic continental shelf and regulates the flow of water towards the Antarctic coastline. The structure and variability of the ASC influences key processes near the Antarctic coastline that have global implications, such as the melting of Antarctic ice shelves and water mass formation that determines the strength of the global overturning circulation. Recent theoretical, modeling, and observational advances have revealed new dynamical properties of the ASC, making it timely to review. Earlier reviews of the ASC focused largely on local classifications of water properties of the ASC's primary front. Here, we instead provide a classification of the current's frontal structure based on the dynamical mechanisms that govern both the along‐slope and cross‐slope circulation; these two modes of circulation are strongly coupled, similar to the Antarctic Circumpolar Current. Highly variable motions, such as dense overflows, tides, and eddies are shown to be critical components of cross‐slope and cross‐shelf exchange, but understanding of how the distribution and intensity of these processes will evolve in a changing climate remains poor due to observational and modeling limitations. Results linking the ASC to larger modes of climate variability, such as El Niño, show that the ASC is an integral part of global climate. An improved dynamical understanding of the ASC is still needed to accurately model and predict future Antarctic sea ice extent, the stability of the Antarctic ice sheets, and the Southern Ocean's contribution to the global carbon cycle
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