Both trace and delay conditioning of evaluative responses depend on contingency awareness

Whereas previous evaluative conditioning (EC) studies produced inconsistent results concerning the role of contingency knowledge, there are classical eye-blink conditioning studies suggesting that declarative processes are involved in trace conditioning but not in delay conditioning. In two EC experiments pairing neutral sounds (conditioned stimuli; CSs) with affective pictures (unconditioned stimuli; USs), we tested whether the type of conditioning procedure affects the relationship between awareness and EC. Auditory CSs and visual USs were either overlapping and co-terminating (Delay Conditioning Group), or they were separated by a short temporal gap (Trace Conditioning Group). In both groups, contingency awareness was manipulated by varying the duration at which the US was presented during conditioning. Furthermore, in addition to a post-conditioning measure of awareness, US detectability was measured concurrently during the learning phase in Experiment 2. US exposure duration affected both measures of awareness. The data of both experiments demonstrate that EC does not occur if the USs are presented at very brief durations, but reliable EC effects can be observed at longer US exposure durations. As there were no differences between trace and delay conditioning, the data suggest that contingency awareness plays a crucial role in trace and in delay conditioning of evaluative responses. These results challenge automatic association-formation accounts of EC, but they are in line with ‘single-process’ accounts assuming EC to be dependent on conscious declarative knowledge about CS–US contingencies.     

Revisiting the relation between contingency awareness and attention: Evaluative conditioning relies on a contingency focus

Although evaluative conditioning has occasionally been demonstrated in the absence of contingency awareness, many recent studies imply that its acquisition depends on the availability of attentional resources during conditioning. In previous experiments attention has typically been manipulated in a general way rather than looking at the particular focus of attention. The present study investigated the role of a focus on the CS–US contingency. Two separate distraction tasks were designed that either diverted attention from the stimuli or directed it to the stimuli while drawing attention away from the contingency between the stimuli. Both types of distraction were shown to eliminate evaluative conditioning. Significant evaluative conditioning was observed in a third group of participants who were required to attend the contingencies. A mediation analysis showed that the observed discrepancy in evaluative conditioning effects between groups was mediated by contingency awareness. The results imply that attention in terms of a stimulus focus is not sufficient for evaluative conditioning to occur. Rather, attention to the contingencies between stimuli appears to be crucial in evaluative conditioning, because it is supposed to foster the acquisition of contingency awareness.     

Revisiting the relation between contingency awareness and attention: evaluative conditioning relies on a contingency focus

Although evaluative conditioning has occasionally been demonstrated in the absence of contingency awareness, many recent studies imply that its acquisition depends on the availability of attentional resources during conditioning. In previous experiments attention has typically been manipulated in a general way rather than looking at the particular focus of attention. The present study investigated the role of a focus on the CS-US contingency. Two separate distraction tasks were designed that either diverted attention from the stimuli or directed it to the stimuli while drawing attention away from the contingency between the stimuli. Both types of distraction were shown to eliminate evaluative conditioning. Significant evaluative conditioning was observed in a third group of participants who were required to attend the contingencies. A mediation analysis showed that the observed discrepancy in evaluative conditioning effects between groups was mediated by contingency awareness. The results imply that attention in terms of a stimulus focus is not sufficient for evaluative conditioning to occur. Rather, attention to the contingencies between stimuli appears to be crucial in evaluative conditioning, because it is supposed to foster the acquisition of contingency awareness.     

Contingency awareness in a symptom learning paradigm: necessary but not sufficient?

In previous studies, we found that bodily symptoms can be learned in a differential conditioning paradigm, using odors as conditioned stimuli (CSs) and CO2-enriched air as unconditioned stimulus (US). However, this only occurred when the odor CS had a negative valence (a selective conditioning effect), and tended to be more pronounced in persons scoring high for Negative Affectivity (NA). This paper considers the necessity and/or sufficiency of awareness of the CS-US contingency in three studies using this paradigm. The relation between contingency awareness and the selective conditioning effect, and between contingency awareness and NA was also considered. Both self reported symptoms and respiratory physiology served as dependent variables. A learning effect on symptoms was found only for participants aware of the CS-US contingency, but not all participants reporting contingency awareness showed a learning effect. No conditioning effects appeared on the physiological measures. Also contingency awareness did not account for the selective conditioning effect, and did not interact with NA. Overall, the necessity but insufficiency hypotheses can only be withhold for group data and not for individual data.     

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.     

Classical conditioning of autonomic fear responses is independent of contingency awareness

The role of contingency awareness in classical conditioning experiments using human subjects is currently under debate. This study took a novel approach to manipulating contingency awareness in a differential Pavlovian conditioning paradigm. Complex sine wave gratings were used as visual conditional stimuli (CS). By manipulating the fundamental spatial frequency of the displays, we were able to construct pairs of stimuli that varied in discriminability. One group of subjects was given an "easy" discrimination, and another was exposed to a "difficult" CS+ and CS-. A 3rd group was exposed to a stimulus that was paired with the unconditional stimulus (UCS) 50% of the time and served as a control. Skin conductance response (SCR) and continuous UCS expectancy data were measured concurrently throughout the experiment. Differential UCS expectancy was found only in the easy discrimination group. Differential SCRs were found in the easy discrimination group as well as in the difficult discrimination group, but not in the 50% contingency control. The difficult discrimination group did not exhibit differential UCS expectancy but did show clear differential SCR. These observations support a dual process interpretation of classical conditioning whereby conditioning on an implicit level can occur without explicit knowledge about the contingencies. The role of contingency awareness in classical conditioning experiments using human subjects is currently under debate. This study took a novel approach to manipulating contingency awareness in a differential Pavlovian conditioning paradigm. Complex sine wave gratings were used as visual conditional stimuli (CS). By manipulating the fundamental spatial frequency of the displays, we were able to construct pairs of stimuli that varied in discriminability. One group of subjects was given an "easy" discrimination, and another was exposed to a "difficult" CS+ and CS-. A 3rd group was exposed to a stimulus that was paired with the unconditional stimulus (UCS) 50% of the time and served as a control. Skin conductance response (SCR) and continuous UCS expectancy data were measured concurrently throughout the experiment. Differential UCS expectancy was found only in the easy discrimination group. Differential SCRs were found in the easy discrimination group as well as in the difficult discrimination group, but not in the 50% contingency control. The difficult discrimination group did not exhibit differential UCS expectancy but did show clear differential SCR. These observations support a dual process interpretation of classical conditioning whereby conditioning on an implicit level can occur without explicit knowledge about the contingencies.     

Aversive conditioning under conditions of restricted awareness: Effects on spatial cueing

In the literature on aversive conditioning there is still debate on the role of awareness. According to some authors, affective learning can occur with or without contingency learning (dual-process model), whereas others argue that a single process produces both affective responses and contingency knowledge. Although many studies have investigated these models, the results to date are inconclusive. Based on a review of the literature, a new series of experiments was designed to examine aversive conditioning in the absence of contingency awareness. In the present study we examined the effects of subliminal aversive conditioning on a spatial cueing task. Awareness was stringently tested after conditioning. Three kinds of awareness were distinguished: contingency awareness (awareness of the CS?US contingencies, where CS is the conditioned stimulus, and US is the unconditioned stimulus), perceptual awareness (awareness of the perceptual differences between the CSs), and US expectancy (awareness of a threat feeling when confronted with the CS+, but not when confronted with the CS?). The results of three experiments demonstrated that responses on the spatial cueing task were modulated by subliminal aversive conditioning. Importantly, none of the participants was contingency aware or able to perceptually discriminate between the conditioned stimuli. However, in Experiment 3, only those participants showing some level of postconditioning expectancy awareness exhibited conditioning effects. These experiments suggest that subliminal aversive conditioning produces small but significant effects, which may be modulated by expectancy awareness.     

Evaluative conditioning may occur with and without contingency awareness

Evaluative conditioning (EC) is considered to play an important role in the attitude formation. One of the ongoing debates in this field concerns the impact of contingency awareness (i.e., awareness of the contingent relationship between conditioned and unconditioned stimulus, CS–US) on the EC occurrence. Despite the claims that EC does not require awareness of CS–US contingencies, the recent studies have claimed just the opposite. However, a number of methodological issues can be raised to undermine those claims. In two experiments, we tried to eliminate potential faults and sought to learn whether EC occurs with or without contingency awareness of either US identity or US valence. We report significant EC effects both with and without contingency awareness. These results provide support for the claim that the EC effects might be produced by independent mechanisms linked to awareness. We also argue that those mechanisms are differently captured by available measures of EC.     

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.     

Implicit threat learning involves the dorsolateral prefrontal cortex and the cerebellum

Background/ObjectiveMost studies investigating the neural correlates of threat learning were carried out using an explicit Pavlovian conditioning paradigm where declarative knowledge on contingencies between conditioned (CS) and unconditioned stimuli (US) is acquired. The current study aimed at understanding the neural correlates of threat conditioning when contingency awareness is limited or even absent.MethodWe conducted an fMRI report of threat learning in an implicit associative learning paradigm called multi-CS conditioning, in which a number of faces were associated with aversive screams (US) such that participants could not report contingencies between the faces and the screams.ResultsThe univariate results showed support for the recruitment of threat-related regions including the dorsolateral prefrontal cortex (dlPFC) and the cerebellum during acquisition. Further analyses by the multivariate representational similarity technique identified learning-dependent changes in the bilateral dlPFC.ConclusionOur findings support the involvement of the dlPFC and the cerebellum in threat conditioning that occurs with highly limited or even absent contingency awareness.     

Evaluative conditioning is pavlovian conditioning: issues of definition, measurement, and the theoretical importance of contingency awareness

In her commentary of Field (1999), Hammerl (1999) has drawn attention to several interesting points concerning the issue of contingency awareness in evaluative conditioning. First, she comments on several contentious issues arising from Field's review of the evaluative conditioning literature, second she critiques the data from his pilot study and finally she argues the case that EC is a distinct form of conditioning that can occur in the absence of contingency awareness. With reference to these criticisms, this reply attempts to address Hammerl's comments by exploring the issues of how awareness is defined, how it is best measured, and whether it is reasonable to believe that EC uniformly occurs in the absence of contingency awareness. The article concludes that the available evidence supports Field's proposition that EC is, in fact, Pavlovian learning. Copyright 2000 Academic Press.     

Reevaluating evaluative conditioning: a nonassociative explanation of conditioning effects in the visual evaluative conditioning paradigm.

In 2 studies, the authors investigated whether evaluative conditioning (EC) is an associative phenomenon. Experiment 1 compared a standard EC paradigm with nonpaired and no-treatment control conditions. EC effects were obtained only when the conditioned stimulus (CS) and unconditioned stimulus (UCS) were rated as perceptually similar. However, similar EC effects were obtained in both control groups. An earlier failure to obtain EC effects was reanalyzed in Experiment 2. Conditioning-like effects were found when comparing a CS with the most perceptually similar UCSs used in the procedure but not when analyzing a CS rating with respect to the UCS with which it was paired during conditioning. The implications are that EC effects found in many studies are not due to associative learning and that the special characteristics of EC (conditioning without awareness and resistance to extinction) are probably nonassociative artifacts of the EC paradigm.     

What do memory data tell us about the role of contingency awareness in evaluative conditioning?

Evaluative conditioning (EC) refers to the effect that pairings of a conditioned stimulus (CS) with a valenced unconditioned stimulus (US) lead to changes in the evaluation of the CS. There have been recurring debates about whether EC requires awareness of the contingency between CSs and USs during learning. We argue that the memory performance data obtained in the standard paradigm remain ambiguous about the role of contingency awareness during the encoding of CS–US pairings. First, memory performance data are unable to distinguish between encoding-related versus retrieval-related effects. Second, the relation between memory performance and evaluation is correlational, which limits conclusions about causal relations between memory performance and EC effects. These ambiguities imply that any possible data pattern can be interpreted in at least two different ways. It is concluded that a resolution of the current debate requires alternative approaches in which contingency awareness is experimentally manipulated during the encoding of CS–US pairings.     

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.     

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。     

Successful differential evaluative conditioning using simultaneous and trace conditioning procedures in the picture-picture paradigm

This paper describes a study designed to investigate the efficacy of two traditional classical conditioning procedures in generating evaluative conditioning (EC) in the picture-picture paradigm in human participants. Differential EC was found using both simultaneous and trace conditioning procedures. In addition, the use of a block-subblock (BSB) nonpaired control condition and full counterbalancing of conditioned stimulus-unconditioned stimulus (CS-UCS) pairings across participants indicated that the observed EC effects were the result of associative learning. Examination of whether successful conditioning could take place with or without conscious awareness of CS-UCS contingencies was inconclusive. The results provide evidence for EC as an associative process and also provide some insight into the possible conditioning parameters that might successfully generate EC.     

Contingency learning with evaluative stimuli: testing the generality of contingency learning in a performance paradigm

In two experiments, we tested the generality of the learning effects in the recently-introduced color-word contingency learning paradigm. Participants made speeded evaluative judgments to valenced target words. Each of a set of distracting nonwords was presented most often with either positive or negative target words. We observed that participants responded faster on trials that respected these contingencies than on trials that contradicted the contingencies. The contingencies also produced changes in liking: in a subsequent explicit evaluative rating task, participants rated positively-conditioned nonwords more positively than negatively-conditioned nonwords. Interestingly, contingency effects in the performance task correlated with this explicit rating effect in both experiments. In Experiment 2, all effects reported were independent of subjective and objective contingency awareness (which was completely lacking), even when awareness was measured at the item level. Our results reveal that learning in this type of performance task extends to nonword-valence contingencies and to responses different from those emitted during the performance task. We discuss the implications of these findings for theories about the processes that underlie contingency learning in performance tasks and for research on evaluative conditioning.     

Effects of awareness and motor involvement on autonomic conditioning in chronic schizophrenics

Chronic schizophrenics under neuroleptic medication were compared with normals, matched for age and education, in two conditioning experiments. Both experiments employed a differential paradigm with long conditional stimulus-unconditional stimulus (CS-UCS) intervals. Skin resistance (SR) and finger pulse or heart rate (HR) were recorded. In Experiment 1, half of the subjects were trained in categorizing the to-be conditional stimuli. In a further step, half of the subjects were informed about the CS-UCS contingency. The UCS was an electric shock. Information improved discrimination of SR responses only of normals, and discrimination training had no effect at all on autonomic responses. In Experiment 2, only electrodermal responders were included. Each subject was tested in two sessions, using a loud tone as UCS in one, and a reaction time signal in the other. Again, half of the subjects were informed about the contingency. Information improved discrimination of SR responses of both diagnostic groups. Decelerations of HR following CS onset showed informed schizophrenics to discriminate better with the loud tone UCS than with the reaction time signal. General autonomic responsivity seems to determine not only discriminative conditioning of schizophrenic patients but also the reports of awareness and the effects of manipulations of awareness. However, when subjects are matched for electrodermal responsivity and are equivalent in terms of SR response conditioning, patients react to information about the contingency with enhanced HR deceleration to the CSs, possibly reflecting a heightened sensitivity of the cardiovascular system.     

Evaluative conditioning and the awareness issue: assessing contingency awareness with the four-picture recognition test

An experiment is described that tested the moderating influence of contingency awareness on evaluative conditioning. After participants were conditioned within the picture-picture paradigm, contingency awareness was assessed by means of a recognition test (i.e., the 4-picture recognition test). Results indicate an inverse relationship between the conditioned affective reaction and contingency awareness: Only participants classified as unaware in the recognition test showed significant effects of evaluative learning. A closer inspection indicates that aware individuals stored not only the valence but also the nominal stimulus in mind.     

The role of CS-US contingency in human evaluative conditioning

Recent studies suggest that in Pavlovian conditioning, two different processes may be operative: signal learning and evaluative learning, resulting in two qualitatively different associative structures. Signal-learning is hypothesized to be responsible for providing us with genuine predictors (CS) for significant events (US). This proposition logically entails that the statistical-correlational relation, i.e. the contingency between CS and US should be a crucial determinant of signal learning. Evaluative conditioning, on the other hand, refers to the observation that the mere pairing of neutral with (dis)liked stimuli changes the valence of the originally neutral stimuli in a (negative) positive direction. As argued elsewhere, evaluative conditioning is probably based on the CS acquiring a mere referential value to the US, without any genuine CS-US expectancy being involved. From this, it was hypothesized that evaluative conditioning might not be dependent on CS-US contingency. Using the standard evaluative conditioning paradigm, four different levels of CS-US contingency were created on a between-subject base. The overall effect of evaluative conditioning was strongly significant, and was not mediated by awareness of the CS-US relation. Of crucial importance, this conditioning effect did not interact with the level of contingency, supporting the hypothesis that CS-US contingency is not a crucial determinant of evaluative conditioning. Moreover, this effect was obtained in a situation in which Ss simultaneously evidenced to have consciously registered quite accurately the different levels of CS-US contingency.