Unmasking latent inhibition in humans

2018 ◽  
Vol 71 (2) ◽  
pp. 380-395
Author(s):  
Daniel R. L. Forrest ◽  
Marius Mather ◽  
Justin A. Harris

Presentations of a to-be-conditioned stimulus (CS) on its own impairs subsequent learning when that CS is paired with an unconditioned stimulus (US). Evidence for this latent inhibition (LI) effect in humans is said to require a “masking task” that diverts attention from the CS during preexposure. We present three experiments that demonstrate LI in humans without masking. Subjects performed a computerised task, making speeded responses to an imperative cue (the US) presented within a continuous stream of stimuli. During preexposure, a to-be-CS was presented 20 times among other stimuli, but excluding the US. Instructions ensured subjects actively monitored all stimuli at this time. This was immediately followed by the training phase, which included the US, the preexposed CS, and a novel CS. Both CSs were reliably followed by the US, but these associations were incidental to the instructed task. Nonetheless, some subjects learned the CS-US associations, responding faster when the US followed a CS than when it was unsignalled. All three experiments also found evidence for LI, in that subjects learned the novel CS-US association sooner than the preexposed CS-US association. We conclude that humans can show LI even when actively attending to the CS during preexposure.

2018 ◽  
Author(s):  
Tobias Heycke ◽  
Christoph Stahl

Evaluative Conditioning (EC) changes the preference towards a formerly neutral stimulus (Conditioned Stimulus; CS), by pairing it with a valent stimulus (Unconditioned Stimulus; US), in the direction of the valence of the US. When the CS is presented subliminally (i.e., too briefly to be consciously perceived), contingency awareness between CS and US can be ruled out. Hence, EC effects with subliminal CSs would support theories claiming that contingency awareness is not necessary for EC effects to occur. Recent studies reported the absence of EC with briefly presented CSs when both CS and US were presented in the visual modality, even though the CSs were identified at above-chance levels. Challenging this finding, Heycke and colleagues (2017) found some evidence for an EC effect with briefly presented visual stimuli in a cross-modal paradigm with auditory USs, but that study did not assess CS visibility. The present study attempted to replicate this EC effect with different stimuli and a CS visibility check. Overall EC for briefly presented stimuli was absent, and results from the visibility check show that an EC effect with briefly presented CSs was only found, when the CSs were identified at above-chance levels.


2016 ◽  
Vol 43 (1) ◽  
pp. 17-32 ◽  
Author(s):  
Xiaoqing Hu ◽  
Bertram Gawronski ◽  
Robert Balas

Evaluative conditioning (EC) is defined as the change in the evaluation of a conditioned stimulus (CS) due to its pairing with a valenced unconditioned stimulus (US). According to propositional accounts, EC effects should be qualified by the relation between the CS and the US. Dual-process accounts suggest that relational information should qualify EC effects on explicit evaluations, whereas implicit evaluations should reflect the frequency of CS–US co-occurrences. Experiments 1 and 2 showed that, when relational information was provided before the encoding of CS–US pairings, it moderated EC effects on explicit, but not implicit, evaluations. In Experiment 3, relational information moderated EC effects on both explicit and implicit evaluations when it was provided simultaneously with CS–US pairings. Frequency of CS–US pairings had no effect on implicit evaluations. Although the results can be reconciled with both propositional and dual-process accounts, they are more parsimoniously explained by propositional accounts.


2021 ◽  
Author(s):  
Mana R Ehlers ◽  
James H Kryklywy ◽  
Andre O Beukers ◽  
Sarah R Moore ◽  
Forys J Brandon ◽  
...  

Learning which stimuli in our environment co-occur with painful or pleasurable events is critical for survival. Previous research has established the basic neural and behavioural mechanisms of aversive and appetitive conditioning; however, it is unclear what precisely is learned. Here we examined what aspects of the unconditioned stimulus (US), sensory and hedonic, are transferred to the conditioned stimulus (CS). To decode the content of brain activation patterns elicited during appetitive (soft touch) and aversive (painful touch) conditioning of faces, a novel variation of representational similarity analysis (RSA) based on theoretically driven representational patterns of interest (POIs) was applied to fMRI data. Once face associations were learned through conditioning, globally the CS reactivated US representational patterns showing conditioning dependent reactivation. More specifically, in higher order brain regions, the CS only reactivated hedonic but not sensory aspects of the US, suggesting that affective conditioning primarily carries forward the valence of the experience rather than its sensory origins.


2019 ◽  
pp. 303-315
Author(s):  
Patrik N. Juslin

This chapter considers the psychological mechanism known as evaluative conditioning. Evaluative conditioning is defined as a process whereby an emotion is evoked by a piece of music just because this stimulus has been paired, repeatedly, with other positive or negative stimuli, which are not necessarily logically connected to the music in any way. It is a special form of classic conditioning that involves the pairing of an initially neutral conditioned stimulus (CS) with an affectively valenced, unconditioned stimulus (US). After the pairing, the CS acquires the ability to arouse the same affective state as the US in the perceiver. The remainder of the chapter discusses the characteristics of evaluative conditioning, the emotions that conditioning might arouse, and the role of conditioning in everyday life.


2021 ◽  
Vol 15 ◽  
Author(s):  
Robert C. Honey ◽  
Dominic M. Dwyer

Pairing a neutral conditioned stimulus (CS) with a motivationally significant unconditioned stimulus (US) results in the CS coming to elicit conditioned responses (CRs). The widespread significance and translational value of Pavlovian conditioning are increased by the fact that pairing two neutral CSs (A and X) enables conditioning with X to affect behavior to A. There are two traditional informal accounts of such higher-order conditioning, which build on more formal associative analyses of Pavlovian conditioning. But, higher-order conditioning and Pavlovian conditioning have characteristics that are beyond these accounts: Notably, the two are influenced in different ways by the same experimental manipulations, and both generate conditioned responses that do not reflect the US per se. Here, we present a formal analysis that sought to address these characteristics.


2021 ◽  
Author(s):  
Philipp C. Paulus ◽  
Aroma Dabas ◽  
Annalena Felber ◽  
Roland Georg Benoit

Humans can vividly simulate hypothetical experiences. This ability draws on our memories (e.g., of familiar people and locations) to construct imaginings that resemble real-life events (e.g., of meeting a person at a location). Here, we examine the hypothesis that we also learn from such simulated episodes much like from actual experiences. Specifically, we show that the mere simulation of meeting a familiar person (unconditioned stimulus; US) at a known location (conditioned stimulus; CS) changes how people value the location. We provide key evidence that this simulation-based learning strengthens pre-existing CS-US associations and that it leads to a transfer of valence from the US to the CS. The data thus highlight a mechanism by which we learn from simulated experiences.


1996 ◽  
Vol 49 (1b) ◽  
pp. 45-59 ◽  
Author(s):  
Simon Killcross ◽  
Anthony Dickinson

Three experiments examined the contextual control of latent inhibition (LI) by the unconditioned stimulus (US) using a within-subjects conditioned suppression procedure with rats. The effect of reducing the context change produced by the introduction of the shock US was investigated by presenting this US during preexposure to the conditioned stimulus (CS). Although limited CS preexposure in the absence of the US had no impact on subsequent conditioning, preexposure in the presence of the shock retarded both excitatory and inhibitory conditioning. We conclude that the introduction of the US during the conditioning phase of a normal LI experiment can produce a contextual change that reduces the observed magnitude of LI.


2020 ◽  
Author(s):  
C. K. Jonas Chan ◽  
Justin Harris

Pavlovian conditioning is sensitive to the temporal relationship between conditioned stimulus (CS) and unconditioned stimulus (US). This has motivated models that describe learning as a process that continuously updates associative strength during the trial or specifically encodes the CS-US interval. These models predict that extinction of responding is also continuous, such that response loss is proportional to the cumulative duration of exposure to the CS without the US. We review evidence showing that this prediction is incorrect, and that extinction is trial-based rather than time-based. We also present two experiments that test the importance of trials versus time on the Partial Reinforcement Extinction Effect (PREE), in which responding extinguishes more slowly for a CS that was inconsistently reinforced with the US than for a consistently reinforced one. We show that increasing the number of extinction trials of the partially reinforced CS, relative to the consistently reinforced CS, overcomes the PREE. However, increasing the duration of extinction trials by the same amount does not overcome the PREE. We conclude that animals learn about the likelihood of the US per trial during conditioning, and learn trial-by-trial about the absence of the US during extinction. Moreover, what they learn about the likelihood of the US during conditioning affects how sensitive they are to the absence of the US during extinction.


2003 ◽  
Vol 56 (1b) ◽  
pp. 80-89 ◽  
Author(s):  
Charlotte Bonardi ◽  
Siaw Yann Ong

This article reviews the recent literature on the topic of learned irrelevance. It asks whether the retardation of subsequent conditioning produced by uncorrelated preexposure is indeed the result of the animal learning that a conditioned stimulus (CS) and unconditioned stimulus (US) are unrelated, or whether it is better explained either as a result of the context specificity of latent inhibition, or as some other artefact of the uncorrelated schedule employed. The conclusion is that there is as yet no good evidence to support the existence of a “genuine” learned irrelevance effect.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bryon Silva ◽  
Claudia Molina-Fernández ◽  
María Beatriz Ugalde ◽  
Eduardo I. Tognarelli ◽  
Cristian Angel ◽  
...  

The most studied form of associative learning inDrosophilaconsists in pairing an odorant, the conditioned stimulus (CS), with an unconditioned stimulus (US). The timely arrival of the CS and US information to a specificDrosophilabrain association region, the mushroom bodies (MB), can induce new olfactory memories. Thus, the MB is considered a coincidence detector. It has been shown that olfactory information is conveyed to the MB through cholinergic inputs that activate acetylcholine (ACh) receptors, while the US is encoded by biogenic amine (BA) systems. In recent years, we have advanced our understanding on the specific neural BA pathways and receptors involved in olfactory learning and memory. However, little information exists on the contribution of cholinergic receptors to this process. Here we evaluate for the first time the proposition that, as in mammals, muscarinic ACh receptors (mAChRs) contribute to memory formation inDrosophila. Our results show that pharmacological and genetic blockade of mAChRs in MB disrupts olfactory aversive memory in larvae. This effect is not explained by an alteration in the ability of animals to respond to odorants or to execute motor programs. These results show that mAChRs in MB contribute to generating olfactory memories inDrosophila.


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