Biomedical subjects

Paul Eelen

Publications and source records attributed to Paul Eelen.

At least 19 recordsLinked to original sources

PubMed2006

Automatic affective stimulus processing is intact after unilateral resection of the anterior temporal lobe in humans.

Only hundreds of milliseconds after an incoming stimulus is perceived, we make an evaluation of whether it is good or bad. This evaluation seems to occur automatically and can significantly influence behavior. According to several functional imaging studies, the amygdala, which is localized in the temporal lobes of the brain, is an important structure for the automatic processing of affective stimuli. To investigate how critical a role the amygdala plays in this process, we had 20 participants with unilateral resection of the temporal lobe and 20 controls perform an affective priming task. Both controls and patients demonstrated shorter response latencies on trials where prime and target had the same valence than on trials where prime and target had the opposite valence. This finding is generally known as the affective priming effect and is considered to reflect automatic stimulus evaluation. More specifically, it is assumed that the valence of the prime stimulus is activated automatically and exerts an influence on the speed by which the target stimulus is evaluated. Given that the affective priming effect is equally large in both groups, our results suggest that the automatic processing of stimulus valence is intact in participants who sustained unilateral resection of the temporal lobe.

Adult↗

PubMed2006

Verbal, behavioural and physiological assessment of the generalization of exposure-based fear reduction in a spider-anxious population.

Clinical fear of spiders was assessed in 39 patients before and after exposure treatment and at a 3-month follow-up. The assessment included behavioral, physiological and self-report measures. Some patients were tested in the treatment context (group Same), while others were tested in a different context (group Different). Both groups demonstrated a significant fear reduction from pre- to post-treatment in all measures, which persisted at the 3-month follow-up. Contrary to our expectations, no clear difference was observed between the groups at any moment. However, a 1-year follow-up test of the self-report measure revealed a return of fear in group Same, but not in group Different. These results show (1) that the effects of exposure treatment persisted over contexts and time in the short term, and (2) that conducting treatment and tests in different contexts enhanced efficiency of exposure treatment in the long term.

Animals↗

PubMed2006

Concurrent excitors limit the extinction of conditioned fear in humans.

In a human fear conditioning experiment, with on-line expectancy ratings and electrodermal responding as indices of fear, two neutral stimuli (pictures of geometric shapes) were first established as reliable predictors of an electric shock. In the subsequent extinction phase, the two stimuli were repeatedly presented in compound, without the shock. The final test phase consisted of individual stimulus presentations again, which resulted in a strong return of the conditioned responses. This effect was not observed in non-conditioned control stimuli. Hence, behavioral effects of extinction seem highly specific to the stimulus constellation that has gone through the extinction procedure. We argue that pharmacological, behavioral and/or cognitive manipulations that could prevent configural processing of stimulus constellations have direct clinical potential.

Conditioning, Psychological↗

PubMed2006

Stronger renewal in human fear conditioning when tested with an acquisition retrieval cue than with an extinction retrieval cue.

It was previously demonstrated in our laboratory that conditioned fear in humans can renew after extinction, when this procedure took place in a different context (ABA-renewal [Vansteenwegen et al. (2005). Return of fear in a human differential conditioning paradigm caused by a return to the original acquisition context. Behaviour Research and Therapy, 43(3), 323-336]). Using the same experimental design, we now tested the power of retrieval cues to interact with this contextual renewal phenomenon. Two groups went through acquisition and extinction (in a different context). They were then tested in the original acquisition context and in the presence of a retrieval cue. In the acquisition-cue group, this cue previously featured during the acquisition procedure; in the extinction-cue group, the cue previously featured during the extinction procedure. As expected, renewal of conditioned electro-dermal responding and retrospective expectancy ratings was strongest in the acquisition-cue group. Theoretical and clinical implications of this finding are discussed.

Association Learning↗

PubMed2006

Determinants and predictive validity of direct and indirect measures of recently acquired food attitudes.

The present study examined whether the affective priming paradigm in the picture-picture naming task can be used to measure recently acquired food attitudes. Food (dis)likes were induced by an evaluative learning procedure in which real food items were contingently paired with sensory liking or expected consequences information. It was found that the picture-picture naming task is capable of measuring recently induced food attitudes irrespective of whether they were based on sensory liking or expected consequences information. In addition, we observed that affective priming effects that are obtained with the naming task can be used to predict food-related choice behaviour, irrespective of whether participants are given time to elaborate on their choice or not. The latter finding, however, emerged only when food attitudes were based on sensory liking.

Adult↗

PubMed2006

Generalization gradients for acquisition and extinction in human contingency learning.

Two experiments investigated the perceptual generalization of acquisition and extinction in human contingency learning. In Experiment 1, the degree of perceptual similarity between the acquisition stimulus and the generalization stimulus was manipulated over five groups. This successfully generated a generalization gradient of acquisition. In the subsequent phase, the response to the generalization stimulus was extinguished in each group. Finally, the acquisition stimulus was presented again. The response recovered differently over groups, thereby establishing the generalization gradient of extinction. In Experiment 2, the acquisition stimulus itself was extinguished before the set of generalization stimuli was tested between groups. One group evidenced a response recovery at test, which suggests that the gradient of acquisition is somewhat broader than the gradient of extinction.

Extinction, Psychological↗

PubMed2006

Resistance to extinction in evaluative conditioning.

A well-demonstrated phenomenon in traditional Pavlovian conditioning research with humans is that of experimental extinction. In contrast, human evaluative conditioning research suggests that evaluative learning shows marked resistance to extinction. Here, the authors replicate both findings concurrently. Two differential fear conditioning experiments with an electrocutaneous stimulus as the unconditioned stimulus evidenced (a) sensitivity to extinction using an autonomic skin-conductance measure and (b) complete resistance to extinction using an affective-priming measure. The results corroborate the idea that evaluative conditioning is more resistant to extinction than is expectancy learning (F. Baeyens, P. Eelen, & G. Crombez, 1995).

Adolescent↗

PubMed2006

Is overgeneral autobiographical memory an isolated memory phenomenon in major depression?

The present study explored the relation between overgeneral autobiographical memory (AM) and other aspects of memory functioning in depression. A total of 26 patients with major depressive disorder completed a set of memory tasks measuring AM specificity (AMT; Williams & Broadbent, 1986), working memory, semantic memory, verbal learning, delayed verbal recall, recognition memory, and source memory. Reduced specificity of AM was related to poor working memory (central executive functioning) and poor source memory. The former finding conforms to the idea that the voluntary retrieval of specific autobiographical memories (AMs) involves central executive processes (e.g., Conway & Pleydell-Pearce, 2000). The latter finding replicates and extends recent findings suggesting that overgeneral AM is part of a broader memory deficit in retrieving the specific details of the context in which information was acquired (Ramponi, Barnard, & Nimmo-Smith, 2004). Furthermore, in line with Ramponi et al. (2004), rumination was found to be related to both overgeneral AM and poor source memory.

Adult↗

PubMed2005

Evaluative conditioning is intact after unilateral resection of the anterior temporal lobe in humans.

Several lesion and functional imaging studies conducted in animals and humans suggest that structures within the amygdaloid nuclear complex (ANC) are important for the occurrence of fear conditioning. Whether this brain structure is also critical for evaluative conditioning, has been investigated less frequently. In the current experiment, a group of participants with unilateral resection of the anterior temporal lobe and a control group received a differential evaluative flavor-taste conditioning task. In the pre-acquisition phase, two fruit flavors (the conditioned stimuli (CSs)) were presented and participants were instructed to evaluate both. In the subsequent acquisition phase, one of these fruit flavors (CS+) was presented together with a bad tasting substance Tween20 (polysorbate 20, the US), while the other flavor (CS-) was never paired with Tween20. Finally, in the post-acquisition phase, the two flavors were presented again without Tween20 and participants were asked to evaluate both of them for a last time. The control group as well as the lesion group rated the CS+ in the post-acquisition phase less favorable than in the pre-acquisition phase, while the ratings of the CS- remained the same in both phases. We clearly demonstrated evaluative conditioning in both test groups. Because the lesion group had still one intact ANC it would be premature, however, to conclude that the ANC is not involved in evaluative conditioning. We conclude that despite evidence for impaired fear conditioning, unilateral damage to the ANC does not impair evaluative conditioning.

Adult↗

PubMed2005

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.

Conditioning, Classical↗

PubMed2005

Return of fear in a human differential conditioning paradigm caused by a stimulus change after extinction.

In a human fear conditioning experiment, 32 participants were trained in a differential conditioning procedure with geometrical shapes as CS+ and CS- (four presentations each), and an electric shock as US. Measures of conditioned responding were skin conductance response (SCR) and retrospective US-expectancy ratings. For half of the participants (Generalization Group, GG), the subsequent extinction phase consisted of four nonreinforced presentations of generalization stimuli (GS+ and GS-). Participants from the Extinction control Group received an equal amount of nonreinforced presentations of the CSs. Finally, all participants were tested with the original CSs. The results from both measures clearly show an increase in the size of the discrimination upon the stimulus change after extinction in the GG. Because this pattern is not observed in the Extinction control Group, extinction performance appears to be somehow restricted to the perceptual characteristics of the extinction stimulus. Interestingly, the size of the conditioned SCR discrimination in the GG is not influenced by the stimulus change after acquisition. This observation points to a differential impact of stimulus change after acquisition vs. extinction treatment. The findings are discussed from the theoretical perspective of renewal and the clinical perspective of Return of Fear.

Analysis of Variance↗

PubMed2005

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.

Adult↗

PubMed2005

Reduced specificity of autobiographical memory: a mediator between rumination and ineffective social problem-solving in major depression?

BACKGROUND: Depressed individuals display a deficit in effectively solving social problem situations (e.g., []). Recent research suggests that rumination may interfere with such effective problem-solving (e.g., []). However, little is known, as yet, about the mechanisms that are underlying this relation between rumination and poor problem-solving. The present study investigated the role of reduced specificity of autobiographical memories as a mediator of this relationship. METHODS: 24 depressed patients (15 women) completed the Autobiographical Memory Test (AMT), the Means-Ends Problem-Solving Task (MEPS), the Ruminative Response Scale (RRS) and the Rumination on Sadness Scale (RSS). RESULTS: Consistent with previous studies, rumination, ineffective problem-solving and reduced memory specificity were significantly associated. Regression analyses further extended these findings by showing that reduced memory specificity mediated the association between rumination and problem-solving effectiveness. LIMITATIONS: The correlational nature of this study limits to some extent the conclusions that can be drawn on the directionality of the observed relationships. CONCLUSIONS: Results offer support for the idea that lack of autobiographical memory specificity mediates the known relationship between rumination and poor problem-solving.

Autobiographies as Topic↗

PubMed2005

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.

Adult↗

PubMed2005

Blocking is sensitive to causal structure in 4-year-old and 8-year-old children.

In a contingency learning task, 4-year-old and 8-year-old children had to predict the outcome displayed on the back of a card on the basis of cues presented on the front. The task was embedded in either a causal or a merely predictive scenario. Within this task, either a forward blocking or a backward blocking procedure was implemented. Blocking occurred in the causal but not in the predictive scenario. Moreover, blocking was affected by the scenario to the same extent in both age groups. The pattern of results was similar for forward and backward blocking. These results suggest that even young children are sensitive to the causal structure of a contingency learning task and that the occurrence of blocking in such a task defies an explanation in terms of associative learning theory.

Child↗

PubMed2005

Unintentional processing of motivational valence.

Recent motivational affective priming studies (Moors & De Houwer, 2001; Moors, De Houwer, & Eelen, 2004) showed that primes that indicate success on a goal-inducing task facilitate positive target responses whereas primes that indicate failure on that task facilitate negative target responses. In the current studies, we examined whether these priming effects depend on consciously intentional processing of the motivational valence of the primes. In Experiment 1, the outcome of success or failure was presented not only immediately before the target (i.e., the prime) but also a second time after the target response. This should encourage participants to ignore the prime. In Experiment 2, participants were asked to respond to the targets within 600 ms after target onset. As a result, participants had little opportunity to process the motivational prime valence in a consciously intentional way. Nevertheless, strong affective priming effects were found in both studies. These results provide additional support for the claim that motivational valence can be processed without the conscious intention to do so.

Adult↗

PubMed2005

Autobiographical memory specificity and emotional abuse.

OBJECTIVE: Examined the relationship between trauma and memory specificity and the importance in this of level of support received. METHOD: Fifty-two female undergraduates completed the Autobiographical Memory Test (AMT; Williams and Broadbent, 1986), assessing memory specificity and the Traumatic Experiences Checklist (TEC; Nijenhuis, Van der Hart, and Vanderlinden, 1999), assessing qualitative aspects of trauma. RESULTS: In low-specific students, those who reported emotional abuse were less specific in their memory. The scores of students who had not received any support for the abuse showed a trend towards retrieval of less specific memories, as compared with those who had received support. CONCLUSION: Results provide evidence for an association between trauma (emotional abuse) and reduced memory specificity, and suggest that receiving support following the abuse might protect individuals from developing over-general memory.

Adolescent↗

PubMed2005

Reduced autobiographical memory specificity as an avoidant coping style.

OBJECTIVE: Previous studies suggest that reduced autobiographical memory specificity might serve as a way of regulating affect. This study examined the relationship between autobiographical memory specificity and avoidant coping. METHOD: Sixty students completed the Autobiographical Memory Test (AMT). Different types of avoidant coping were assessed using questionnaires: the Acceptance and Action Questionnaire, the Cognitive-Behavioural Avoidance Scale and the White Bear Suppression Inventory. RESULTS: For all questionnaires, a significant correlation was observed between the number of specific responses on the AMT and an avoidant coping style. More avoidance was associated with fewer specific answers. These correlations remained when corrected for number of omissions. CONCLUSION: The results provide further evidence for the affect-regulating quality of autobiographical memory specificity.

Adaptation, Psychological↗