The development of cued versus contextual conditioning in a predictable and an unpredictable human fear conditioning preparation

In this human fear conditioning study, the online development of conditioned US-expectancy to discrete cues and background contexts was measured in two groups. In the paired group (n=30), the CS was systematically followed by an aversive shock (US). In the unpaired group (n=30), CS and US were presented explicitly unpaired. Using US-expectancy ratings, we replicated the basic finding already illustrated in humans with startle modulation. In the paired group, the CS elicited more US-expectancy than the context, whereas in the unpaired group, the context elicited more US-expectancy than the CS. Interestingly, we also observed a trial-by-trial development of conditioning to the context in the unpaired group as indicated by a significant linear trend. This gradual development and the evidence for the role of US-expectancy in contextual fear add to the idea that cued and contextual fear rely on the same basic associative processes.     

Overgeneral autobiographical memory predicts diagnostic status in depression

Major depressive disorder (MDD) is characterised by difficulties in retrieving specific autobiographical memories, with a significant propensity towards categoric memories (i.e. memories of a summary type). Previous studies have demonstrated that this overgeneral memory is a valid predictor of the course of depression, with reduced specificity being associated with worse outcome. Most of these studies have employed continuous measures of depression to assess the course of the symptoms. This study investigated whether overgeneral memory also predicts clinical status at follow-up (i.e. whether patients still meet criteria for depression). Patients who fulfilled criteria for major depressive disorder were tested shortly after admission to the hospital and were retested some weeks later. It was found that lower levels of specificity or a higher number of categoric memories were associated with a higher probability of still being diagnosed with MDD. These memory variables outperformed other relevant indices, such as depression severity, rumination, level of self-esteem and dysfunctional attitudes.     

A sentence completion procedure as an alternative to the Autobiographical Memory Test for assessing overgeneral memory in non-clinical populations

Overgeneral memory (OGM) has been proposed as a vulnerability factor for depression (Williams et al., 2007) or depressive reactivity to stressful life-events (e.g., Gibbs & Rude, 2004). Traditionally, a cue word procedure known as the Autobiographical Memory Test (AMT; Williams & Broadbent, 1986) is used to assess OGM. Although frequently and validly used in clinical populations, there is evidence suggesting that the AMT is insufficiently sensitive to measure OGM in non-clinical groups. Study 1 evaluated the usefulness of a sentence completion method to assess OGM in non-clinical groups, as an alternative to the AMT. Participants were 197 students who completed the AMT, the Sentence Completion for Events from the Past Test (SCEPT), a depression measure, and visual analogue scales assessing ruminative thinking. Results showed that the mean proportion of overgeneral responses was markedly higher for the SCEPT than for the standard AMT. Also, overgeneral responding on the SCEPT was positively associated to depression scores and depressive rumination scores, whereas overgeneral responding on the AMT was not. Results suggest that the SCEPT, relative to the AMT, is a more sensitive instrument to measure OGM, at least in non-clinical populations. Study 2 further showed that this enhanced sensitivity is most likely due to the omission of the instruction to be specific rather than to the SCEPT's sentence completion format (as opposed to free recall to cue words).     

Automatic non-associative semantic priming: episodic affective priming of naming responses

Affective priming for associatively unrelated prime-target pairs was investigated using (a) the naming task, (b) a short stimulus onset asynchrony (250 ms), and (c) primes that had acquired their affective connotation during a differential evaluative conditioning procedure. Despite the fact that the primes and the targets were related on the affective dimension only, significant priming emerged. This finding indicates that mere affective overlap is sufficient to produce automatic priming. As such, our results are in line with theoretical accounts of automatic priming that are based on semantic relatedness.     

Extinction and renewal of Pavlovian modulation in human sequential Feature Positive discrimination learning

Using a conditioned suppression task, we investigated extinction and renewal of Pavlovian modulation in human sequential Feature Positive (FP) discrimination learning. In Experiment 1, in context a participants were first trained on two FP discriminations, X-->A+/A- and Y-->B+/B-. Extinction treatment was administered in the acquisition context a (aaa group) or in a new context b (aba group), and comprised X-->A- extinction and Y- control trials. Discriminative X-->A/A responding was lost in both groups when tested in the extinction context, but partially recovered in the aba and not in the aaa group when tested in the acquisition context, suggesting extinction and renewal of extinguished modulation. The same was observed for the Y-->B/B control pair, however, questioning whether the loss of discriminative X-->A/A responding represented genuine extinction of modulation. In Experiment 2, including only aba groups, participants were trained in context a on two FP discriminations, X-->A+/A- and Y-->B+/B-, after which the group "Extinction" was exposed to X-->A- extinction trials in context b, whereas the group "Control" was exposed to X- control trials; concurrently, both groups received further Y-->B+/B- training. In the group Control, differential Y-->B/B and X-->A/A responding were acquired and maintained throughout the experiment. In the group Extinction, while Y-->B/B responding was also maintained throughout, differential X-->A/A responding disappeared because of X-->A- extinction treatment when tested in the extinction context b, but partially reappeared when tested in the acquisition context a. This evidences aba-renewal of extinguished modulation.     

Affective priming as an indirect measure of food preferences acquired through odor conditioning

The present study aimed at investigating affective priming for originally neutral food stimuli that recently acquired their affective meaning through odor conditioning. In a first phase, pictures of different brands of yogurts (CSs) were contingently presented with a positive or negative odor (US). In a subsequent phase, the yogurt CSs were used as primes in an affective priming procedure. Rating data showed that the acquisition procedure resulted in a reliable evaluative learning effect. This could be corroborated by the results of the priming task. Participants responded faster to positive target words and made fewer errors when they were preceded by a CS that had been associated with a positive odor, as compared to a CS that was associated with a negative odor. A reversed pattern was present for negative targets. Based on these findings, it is suggested that affective priming might be used as a demand-free measure of evaluative learning.     

Return of fear in a human differential conditioning paradigm caused by a return to the original acquistion context

In a differential human fear conditioning paradigm evidence for ABA-renewal was obtained manipulating the lighting in the experimental room. During acquisition in either a dark or illuminated room, one neutral slide was sometimes paired with a loud aversive noise whereas another slide was not. Subsequently, extinction took place in the opposite lighting context. When afterwards the participants were tested again in the original acquisition context, measurements revealed a recovery of the conditioned electrodermal response and an increase in the retrospective verbal US-expectancy ratings. No response recovery was obtained in an AAA-group that received acquisition, extinction and test trials in one and the same context. Several theoretical explanations for this type of return of fear as well as implications for clinical practice are discussed.     

Reinstatement of fear responses in human aversive conditioning

The treatment of choice for a number of anxiety disorders is exposure therapy. However, successful reduction of fear through exposure is sometimes followed by a (partial) return of symptoms of fear (return of fear, ROF; Clin. Psychol. Rev. 9 (1989) 147). Several possible learning mechanisms have been suggested to explain ROF (e.g. mechanisms related to spontaneous recovery, renewal, reacquisition and reinstatement). The present study focuses on reinstatement, which refers to the observation that mere US-only presentations can 'reinstate' previously extinguished fear responses. Although animal research has repeatedly demonstrated this phenomenon, little is known about fear reinstatement in humans. The present study employed a differential aversive conditioning procedure: after acquisition and a subsequent extinction procedure, a series of four unpredicted US-only trials was scheduled in the reinstatement group. The control group did not receive additional US presentations. A significant reinstatement effect was observed for US-expectancy ratings and fear ratings in the reinstatement group, but not in the control group. No differences were observed in a reaction time measure of resource allocation to the conditioned stimuli. These findings constitute a first demonstration of reinstatement of conditioned fear responses in humans. Implications for exposure treatment and suggestions for future research are discussed.     

A time course analysis of the affective priming effect

The argument that automatic processes are responsible for affective/evaluative priming effects has been primarily based on studies that have manipulated the stimulus onset asynchrony (SOA; i.e., the interval between the onset of the prime and the onset of the target). Moreover, these SOA studies provide an insight in the time course of the activation processes underlying automatic affect/attitude activation. Based on a fine-grained manipulation of the SOA employing either the evaluative decision task (Experiment 1) and the pronunciation task (Experiment 2) we concluded that affective priming, and hence automatic affect activation, is based on fast-acting automatic processes. The results of Experiment 3 provide a valid explanation for an apparent discrepancy between the results of Experiments 1 and 2 and previous findings. Finally, the results of Experiment 3 support the prediction of Jarvis and Petty (1996) that affective priming effects should be stronger for participants who are more chronically engaged in conscious evaluations.     

Norms of valence, arousal, dominance, and age of acquisition for 4,300 Dutch words

This article presents norms of valence/pleasantness, activity/arousal, power/dominance, and age of acquisition for 4,300 Dutch words, mainly nouns, adjectives, adverbs, and verbs. The norms are based on ratings with a 7-point Likert scale by independent groups of students from two Belgian (Ghent and Leuven) and two Dutch (Rotterdam and Leiden-Amsterdam) samples. For each variable, we obtained high split-half reliabilities within each sample and high correlations between samples. In addition, the valence ratings of a previous, more limited study (Hermans & De Houwer, Psychologica Belgica, 34:115-139, 1994) correlated highly with those of the present study. Therefore, the new norms are a valuable source of information for affective research in the Dutch language.