Hating the cute kitten or loving the aggressive pit-bull: EC effects depend on CS–US relations

Evaluative conditioning (EC) refers to valence changes of initially neutral stimuli (CSs) through repeated pairings with positive or negative stimuli (USs). The current study is about the moderating role of qualifiers that specify the CS–US relation during these pairings. We show successful EC with pictures of men (CSs) and of liked/disliked animals or landscapes (USs). More importantly, the same pairings resulted in standard and reversed EC effects depending on semantic qualifier of the CS–US relation. CSs loving positive (negative) USs became more positive (negative), while CSs loathing positive (negative) USs became more negative (positive). These data favour a propositional EC account (De Houwer, 2009) over a purely associative account, as they show that it is not only relevant that CS and US are related, but how they are related.     

Evaluative conditioning without directly experienced pairings of the conditioned and the unconditioned stimuli

Evaluative conditioning (EC) is the valence change of a stimulus (conditioned stimulus, CS) that is due to the previous pairing with another stimulus (unconditioned stimulus, US). We investigated whether EC can occur also when the CS–US pairings are not experienced directly by the participant but are implied by other events that the participant encounters. In two experiments, positive USs were presented in some trials and negative USs in other trials. Afterwards, participants were given information from which it was possible to conclude that CSs were covertly present during these trials. Finally, the valence of these CSs was registered using both implicit (Implicit Association Test, affective priming) and explicit measures (valence ratings). In line with the assumption that EC effects can be based on CS–US pairings that are not directly experienced, the valence of the CSs changed in the direction of the US with which they were covertly paired. This effect was observed both on explicit and on implicit measures. We argue that several aspects of our results are in line with propositional models of EC and fit less well with association formation models.     

Evaluative conditioning without directly experienced pairings of the conditioned and the unconditioned stimuli

Evaluative conditioning (EC) is the valence change of a stimulus (conditioned stimulus, CS) that is due to the previous pairing with another stimulus (unconditioned stimulus, US). We investigated whether EC can occur also when the CS-US pairings are not experienced directly by the participant but are implied by other events that the participant encounters. In two experiments, positive USs were presented in some trials and negative USs in other trials. Afterwards, participants were given information from which it was possible to conclude that CSs were covertly present during these trials. Finally, the valence of these CSs was registered using both implicit (Implicit Association Test, affective priming) and explicit measures (valence ratings). In line with the assumption that EC effects can be based on CS-US pairings that are not directly experienced, the valence of the CSs changed in the direction of the US with which they were covertly paired. This effect was observed both on explicit and on implicit measures. We argue that several aspects of our results are in line with propositional models of EC and fit less well with association formation models.     

Extinction of likes and dislikes: effects of feature-specific attention allocation

The evaluative conditioning (EC) effect refers to the change in the liking of a neutral stimulus (conditioned stimulus, CS) due to its pairing with another stimulus (unconditioned stimulus, US). We examined whether the extinction rate of the EC effect is moderated by feature-specific attention allocation. In two experiments, CSs were abstract Gabor patches varying along two orthogonal, perceptual dimensions (i.e. spatial frequency and orientation). During the acquisition phase, one of these dimensions was predictive of the valence of the USs. During the extinction phase, CSs were presented alone and participants were asked to categorise the CSs either according to their valence, the perceptual dimension that was task-relevant during the acquisition phase, or a perceptual dimension that was task-irrelevant during the acquisition phase. As predicted, explicit valence measures revealed a linear increase in the extinction rate of the EC effect as participants were encouraged to assign attention to non-evaluative stimulus information during the extinction phase. In Experiment 1, Affect Misattribution Paradigm (AMP) data mimicked this pattern of results, although the effect just missed conventional levels of significance. In Experiment 2, the AMP data revealed an increase of the EC effect if attention was focused on evaluative stimulus information. Potential mechanisms to explain these findings are discussed.     

Subjective,physiological, and behavioural responses towards evaluatively conditioned stimuli

Evaluative Conditioning (EC) is commonly defined as the change in liking of a stimulus (conditioned stimulus, CS) due to its pairings with an affective unconditioned stimulus (US). In Experiment 1, we investigated effects of repeated stimulus pairings on affective responses, i.e. valence and arousal ratings, pupil size, and duration estimation. After repeatedly pairing the CSs with affective USs, a consistent pattern of affective responses emerged: The CS_negative was rated as being more negative and more arousing, resulted in larger pupils, and was temporally overestimated compared to the CS_neutral. In Experiment 2, the influence of a mere instruction about the contingency between a CS and US on affective responses was examined. After mere instruction about upcoming pairings between the CS and US, subjective ratings also changed, but there was neither evidence for differential pupillary responses nor for differential temporal processing. The results indicate that EC via pairings or instructions can change the affective responses towards formerly neutral stimuli and introduce pupil size as a physiological measure in EC research. However, Experiment 2 suggests that there might be moderating factors based on the type of EC procedure involved.     

I like it because I said that I like it: evaluative conditioning effects can be based on stimulus-response learning

Evaluative conditioning (EC) effects are often assumed to be based on a learned mental link between the CS (conditioned stimulus) and the US (unconditioned stimulus). We demonstrate that this link is not the only one that can underlie EC effects, but that if evaluative responses are actually given during the learning phase also a direct link between the CS and an evaluative response-a CS-ER link-can be learned and lead to EC effects. In Experiment 1, CSs were paired with USs and participants were asked to evaluate the pairs during the conditioning phase. Resulting EC effects were unaffected by a later revaluation of the USs, suggesting that these EC effects can be attributed to CS-ER learning rather than to CS-US learning. Experiment 2 replicated Experiment 1 with the difference that no evaluative responses were given during the learning phase. EC effects in this study were influenced by US revaluation, suggesting that these EC effects are mainly based on CS-US learning. In Experiment 3, it was shown that EC effects can be found even if the USs are entirely removed from the procedure and the CSs are only paired with enforced evaluative responses. Together the experiments show that the valence of a stimulus can change because of a contingency with an evaluative response. (PsycINFO Database Record (c) 2011 APA, all rights reserved).     

Changing CS features alters evaluative responses in evaluative conditioning

Evaluative conditioning (EC) refers to changes in people's evaluative responses toward initially neutral stimuli (CSs) by mere spatial and temporal contiguity with other positive or negative stimuli (USs). We investigate whether changing CS features from conditioning to evaluation also changes people's evaluative response toward these CSs. We used computer-generated male faces as CSs and paired them with other positively or negatively evaluated faces. When participants evaluated the CS faces, they either appeared unchanged, with glasses, with beards, or glasses and beards. Unchanged faces showed a clear conditioning effect, while all other face versions showed no significant conditioning effects. The conditioning effect also depended on participants’ awareness of a CS's respective US. These results mirror configural explanations of stimulus generalization in classical conditioning, with implications for EC as explanation for attitude acquisition and learning of likes and dislikes in everyday life.     

Is evaluative conditioning really resistant to extinction? Evidence for changes in evaluative judgements without changes in evaluative representations

Evaluative conditioning (EC) is defined as the change in the evaluation of a conditioned stimulus (CS) due to its pairing with a positive or negative unconditioned stimulus (US). Although several individual studies suggest that EC is unaffected by unreinforced presentations of the CS without the US, a recent meta-analysis indicates that EC effects are less pronounced for post-extinction measurements than post-acquisition measurements. The disparity in research findings suggests that extinction of EC may depend on yet unidentified conditions. In an attempt to uncover these conditions, three experiments (N = 784) investigated the influence of unreinforced post-acquisition CS presentations on EC effects resulting from simultaneous versus sequential pairings and pairings with single versus multiple USs. For all four types of CS–US pairings, EC effects on self-reported evaluations were reduced by unreinforced CS presentations, but only when the CSs had been rated after the initial presentation of CS–US pairings. EC effects on an evaluative priming measure remained unaffected by unreinforced CS presentations regardless of whether the CSs had been rated after acquisition. The results suggest that reduced EC effects resulting from unreinforced CS presentations are due to judgement-related processes during the verbal expression of CS evaluations rather than genuine changes in the underlying evaluative representations.     

At the crossroads: Attention,contingency awareness,and evaluative conditioning

Evaluative conditioning (EC) refers to changes in the evaluation of a conditioned stimulus (CS) due to its repeated pairing with an unconditioned stimulus (US). One of the most debated topics in EC research is whether or not EC is dependent on contingency awareness. In this study, we go beyond this debate by examining whether contingency awareness mediates the impact of attentional resources and goal-directed attention on EC. Attentional resources were manipulated by presenting CSs and USs either within the same modality or in different modalities. Goal-directed attention was manipulated by asking participants to respond to the CSs or to the USs. Results indicate that the effect of goal-directed attention on EC is mediated by contingency awareness, whereas the effect of attentional resources on EC is not.     

Evaluative conditioning of high-novelty stimuli does not seem to be based on an automatic form of associative learning

Evaluative conditioning (EC) refers to the change in valence of initially neutral stimuli (conditioned stimuli, or CSs) as a result of their pairing with positive or negative stimuli (unconditioned stimuli, or USs). EC is critical to dual-attitudes models as it is often presented as an evaluative effect that results from a purely automatic form of associative learning. Although evidence suggests that EC does not occur without contingency awareness, Ruys, and Stapel (2009) recently argued that contingency awareness is unnecessary for high-novelty stimuli. Researchers may thus be tempted to conclude that EC rests on an automatic form of associative learning, at least for CSs associated with little prior evaluative knowledge. Taking issue with this claim, the present study reveals that EC of high-novelty stimuli is dependent on attentional resources. The role of contingency awareness in EC of high-novelty stimuli is also discussed.     

Reinstatement of fear in humans: autonomic and experiential responses in a differential conditioning paradigm

The present study investigated reinstatement of fear in humans using an aversive differential conditioning paradigm. Two neutral human face pictures were presented during habituation, acquisition, extinction, and postreinstatement phases. One picture served as a conditioned stimulus (CS) reinforced by an unconditioned stimulus (US) in the form of electrical stimulation (CS+) and the second picture as a control stimulus that was never reinforced (CS-). The prediction that in a reinstatement manipulation a previously extinguished fear response in humans can be reinstated in a reinstatement group by the mere presentation of three unpredicted electrical stimulations (USs) was tested. Participants in the control group were not exposed to unpredicted USs and no reinstatement effect was expected. Outcome measures included subjective US expectancy ratings and skin conductance responses. Results showed non-selective return of the fear response due to fear recovery associated with both CSs (CS+/CS-) in the reinstatement group. Unexpected fear recovery was observed for both CSs (CS+/CS-) in control participants. Results are discussed with respect to context conditioning, fear generalisation, and anxiety-related cognitive mechanisms underlying fear recovery after extinction.     

Aware and (dis)liking: item-based analyses reveal that valence acquisition via evaluative conditioning emerges only when there is contingency awareness

Evaluative conditioning (EC) refers to changes in the liking of an affectively neutral stimulus (the conditioned stimulus, or CS) following the pairing of that stimulus with another stimulus of affective value (the unconditioned stimulus, or US). In 3 experiments, the authors assessed contingency awareness, that is, awareness of the CS-US associations, by relying on participants' responses to individual items rather than using a global method of assessment. They found that EC emerged on contingency aware CSs only. Of note, whether the CSs were evaluated explicitly (Experiments 1 and 2) or implicitly (Experiment 3) did not make a difference. This pattern supports the idea that awareness of the CS-US associations may be required for valence acquisition via EC.     

Expectancy-learning and evaluative learning in human classical conditioning: affective priming as an indirect and unobtrusive measure of conditioned stimulus valence

It has been argued that in classical conditioning two processes might be operative. First, one may learn that the conditioned stimulus (CS+) is a valid predictor for the occurrence of the biologically negative or positive event (US; expectancy-learning). Second, one may learn to perceive the conditioned stimulus itself as a negative or positive stimulus, depending on the valence of the event it has been associated with (evaluative learning). Until the present, however, both forms of learning have been investigated using rather different conditioning procedures. Using a differential aversive conditioning preparation with pictures of human faces as CSs and an electrocutaneous stimulus as US, we were able to demonstrate that both forms of learning can co-occur. Moreover, the extent of evaluative learning in this aversive conditioning procedure did not significantly differ from the amount of evaluative learning in an evaluative conditioning procedure with positive and negative adjectives as USs, which was administered to the same participants. In the present study evaluative learning was not only indexed by direct evaluative ratings, but we introduced affective priming as an indirect and unobtrusive, reaction time based measure of stimulus valence. Finally, imagery instructions during acquisition did not facilitate expectancy-learning nor evaluative learning.     

Is the devil in the detail? Evidence for S-S learning after unconditional stimulus revaluation in human evaluative conditioning under a broader set of experimental conditions

Whether valence change during evaluative conditioning is mediated by a link between the conditional stimulus (CS) and the unconditional stimulus (US; S-S learning) or between the CS and the unconditional response (S-R learning) is a matter of continued debate. Changing the valence of the US after conditioning, known as US revaluation, can be used to dissociate these accounts. Changes in CS valence after US revaluation provide evidence for S-S learning but if CS valence does not change, evidence for S-R learning is found. Support for S-S learning has been provided by most past revaluation studies, but typically the CS and US have been from the same stimulus category, the task instructions have suggested that judgements of the CS should be based on the US, and USs have been mildly valenced stimuli. These factors may bias the results in favour of S-S learning. We examined whether S-R learning would be evident when CSs and USs were taken from different categories, the task instructions were removed, and more salient USs were used. US revaluation was found to influence explicit US evaluations and explicit and implicit CS evaluations, supporting an S-S learning account and suggesting that past results are stable across procedural changes.     

评价性条件反射效应：无条件刺激的呈现时长、效价强度与关联意识的作用

以真实商标图案为条件刺激, 情绪图片为无条件刺激, 探索无条件刺激呈现时长、效价强度与关联意识对评价性条件反射效应的影响。实验通过结合四图再认测验与基于项目分析, 对关联意识的作用进行了详细探讨。结果表明, 评价性条件反射效应只发生在无条件刺激长呈现水平与无条件刺激强效价水平; 评价性条件反射效应的产生需要基于被试的关联意识。关联意识在呈现时长(效价强度)与评价性条件反射效应间的中介作用不显著。结果不支持评价性条件反射的内隐错误归因机制及联想-命题评价模型的相关论断, 部分支持命题性解释模型。     

Using the Implicit Association Test does not rule out an impact of conscious propositional knowledge on evaluative conditioning

Implicit measures such as the Implicit Association Test (IAT) have recently become popular as tools in research on evaluative conditioning. The reason is that these measures are thought to be impervious to changes in valence that are due to conscious propositional knowledge about the relation between the conditioned stimulus (CS) and the unconditioned stimulus (US). I present data that raise doubts about the validity of this assumption. In two experiments, attitudes towards CSs as measured by the IAT were in line with instructed CS-US contingencies even though the CSs and USs were never actually paired. The results therefore suggest that IAT effects can be biassed by conscious propositional knowledge.     

What you see is what will change: Evaluative conditioning effects depend on a focus on valence

This study investigated whether evaluative conditioning (EC) effects depend on an evaluative focus during the learning phase. An EC effect is a valence change of an originally neutral stimulus (conditioned stimulus or CS) that is due to the former pairing with a positive or negative stimulus (unconditioned stimulus or US). In three experiments, the task focus during the conditioning phase was manipulated. Participants judged CS–US pairings either with respect to their valence or with respect to another stimulus dimension. EC effects on explicit and implicit measures were found when valence was task relevant but not when the non-valent stimulus dimension was task relevant. Two accounts for the valence focus effect are proposed: (1) An additional direct learning of the relation of CS and evaluative responses in the valence focus condition, or (2) a stronger activation of US valence in the valence focus condition compared to the non-valent focus condition.     

Event representation in Pavlovian conditioning: image and action

In a typical Pavlovian conditioning experiment, a relatively insignificant event, the conditioned stimulus (CS), is paired with a biologically more meaningful event, the unconditioned stimulus (US). As a consequence of those pairings, the CS is thought to acquire response characteristics of the US. In this article I describe experiments with rats that suggest that under some circumstances, the CS acquires control of perceptual processing of the US, in the absence of that US itself. I present three kinds of evidence for this surrogate processing, which I liken to imagery or hallucination: (1) CSs come to control specific, sensory-evaluative responses normally evoked only by the USs; (2) CSs can substitute for USs in the establishment of new learning about those USs themselves; (3) CSs can substitute for USs in the modulation of conditioning to other events, either overshadowing (interfering) or potentiating learning, in the same manner as the USs themselves. Finally, I compare these data with evidence for conditioned sensation and imagery in humans, and suggest that imagery may be a very basic process, evolutionarily derived from perceptual and conditioning processes adapted to deal with remote or absent objects.     

Non-differential return of fear in humans after a reinstatement procedure

The present experiment investigated reinstatement of fear in humans using a differential fear conditioning preparation. In this experiment, one neutral stimulus (conditioned stimulus; CS+) was paired with an aversive stimulus (unconditioned stimulus; US) during the acquisition phase, while another neutral stimulus was not (CS−). This procedure led to a difference in responding between the CS+ and the CS− (i.e., differential conditioning). After this acquisition phase, an extinction phase followed, during which both CSs were presented without the US, resulting in a decrease in differential conditioned responding. Reinstatement refers to the return of extinguished conditioned responses due to the experience of US-only trials after the extinction phase. This phenomenon was investigated by presenting half of the participants (reinstatement group) with unpredictable USs after the extinction phase. The control group did not receive these USs after the extinction procedure. The results show that return of fear was clearly apparent after the reinstating USs. This return of fear was, however, not limited to the CS+. An increase in ‘conditioned’ responding was also observed for the control stimulus. This interesting observation will be discussed against the background of a number of recent theoretical conceptualizations of reinstatement.     

What you see is what will change: evaluative conditioning effects depend on a focus on valence

This study investigated whether evaluative conditioning (EC) effects depend on an evaluative focus during the learning phase. An EC effect is a valence change of an originally neutral stimulus (conditioned stimulus or CS) that is due to the former pairing with a positive or negative stimulus (unconditioned stimulus or US). In three experiments, the task focus during the conditioning phase was manipulated. Participants judged CS-US pairings either with respect to their valence or with respect to another stimulus dimension. EC effects on explicit and implicit measures were found when valence was task relevant but not when the non-valent stimulus dimension was task relevant. Two accounts for the valence focus effect are proposed: (1) An additional direct learning of the relation of CS and evaluative responses in the valence focus condition, or (2) a stronger activation of US valence in the valence focus condition compared to the non-valent focus condition.