References of "Willems, Sylvie"
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See detailDoes implicit memory during anaesthesia persist in children?
Lopez, Ursula; Habre, w; Laurencon, M. et al

in British Journal of Anaesthesia (2009), 102(3), 37984

Background. Recent studies suggest that implicit memory (especially perceptual implicit memory) persists during adequate general anaesthesia in adults. Studies in children, however, have failed to ... [more ▼]

Background. Recent studies suggest that implicit memory (especially perceptual implicit memory) persists during adequate general anaesthesia in adults. Studies in children, however, have failed to demonstrate implicit memory during general anaesthesia, possibly because of differences in methodological design. We therefore designed a prospective study with the aim of evaluating implicit memory in children undergoing general anaesthesia, using a perceptual memory test based on the mere exposure effect, previously tested in a control group. Methods. Twelve infrequent neutral words were played 12 times in a random sequence via headphones to 36 children aged 8–12 yr during elective or emergency surgery. The children were not premedicated, and general anaesthesia was maintained with isoflurane. The word presentation started immediately after the surgical incision. Within 36 h after the stimulus presentation, the memory was assessed by using a forced-choice preference judgement task. Time constraint and word deterioration with a low-pass filter were used to prevent the subjects from utilizing intentional retrieval. The implicit memory score was obtained by calculating the proportion of target words preferred, which was compared with the chance level (0.5). Results. The percentage of correct responses given by the children was comparable with the chance level. The memory score was mean (SD) 0.48 (0.16) (95% CI 0.43–0.53). Conclusions. The use of a perceptual implicit memory test based on the mere exposure procedure in children failed to reveal any evidence of implicit memory under general anaesthesia. [less ▲]

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See detailFalse memory and surprise: round #3
Willems, Sylvie ULg; Dehon, Hedwige ULg

Poster (2008, May)

Three experiments examined the links between surprise feeling and a false memory phenomenon, the Deese-Roediger-McDermott (DRM) effect. In DRM paradigm, subjects studied lists of related words (NIGHT ... [more ▼]

Three experiments examined the links between surprise feeling and a false memory phenomenon, the Deese-Roediger-McDermott (DRM) effect. In DRM paradigm, subjects studied lists of related words (NIGHT, DREAM, etc.) that were associated with non-presented critical word (e.g., SLEEP) for which high false recognition rate is after noted. Roediger and coll. (in press) suggested that this effect occur because critical words are highly activated by their semantic association with words that are in the list. Whittlesea et al. (2005) proposed an alternative explanation, based on the discrepancy-attribution hypothesis. According to that account, false recognition results when a feeling of surprise comes from a discrepancy between subject’s expectation about processing fluency and real processing fluency. When Whittlesea and coll. have provided a range of evidences for this account, Roediger and coll. found that subjects were not surprised when they encountered non-presented critical word during recognition test. We explained these discrepant findings by methodology differences between these two studies. Whittlesea et al. noted that various procedures that eliminate surprise eliminate the false memories. However, they used a modified DRM procedure (e.g., RSVP presentations and recognition judgment for each critical word directly after the study of each list of related words). In contrast, Roediger and coll. used a classical DRM procedure but did not eliminate surprise feeling. Rather, they investigated whether subjects experienced the critical word as surprising by asking them to make judgments of surprise on a recognition test. In this study, we used various procedures that eliminate surprise like Whittlesea but we used classical DRM paradigm like Roediger. Experiment 1 replicates the DRM effect. Experiment 2 & 3 shows that the DRM effect is decreased but not abolished when participants are prevented from being surprised by critical word. It is proposed that experience of surprise participate to DRM effect, but not alone. [less ▲]

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See detailFalse memories and Surprise: Round #3
Willems, Sylvie ULg; Dehon, Hedwige ULg

Poster (2008, May)

Three experiments examined the links between feeling of surprise and a false memory phenomenon, the Deese-Roediger-McDermott (DRM) effect. In DRM paradigm, subjects studied lists of related words (NIGHT ... [more ▼]

Three experiments examined the links between feeling of surprise and a false memory phenomenon, the Deese-Roediger-McDermott (DRM) effect. In DRM paradigm, subjects studied lists of related words (NIGHT, DREAM, etc.) that were associated with non-presented critical word (e.g., SLEEP) for which high false recognition rate is after noted. Whittlesea et al. (2005) proposed that false recognition results when a feeling of surprise comes from a discrepancy between subject’s expectation about processing fluency and real processing fluency. When Whittlesea and coll. have provided a range of evidences for this account, Roediger and coll. (in press) found that subjects were not surprised when they encountered non-presented critical word during recognition test. We explained these discrepant findings by methodology differences between these two studies. Whittlesea et al. noted that various procedures that eliminate surprise eliminate the false memories. However, they used a modified DRM procedure (e.g., RSVP presentations). In contrast, Roediger and coll. used a classical DRM procedure but did not eliminate surprise feeling. Rather, they investigated whether subjects experienced the critical word as surprising by asking them to make judgments of surprise on a recognition test. In this study, we used various procedures that eliminate surprise like Whittlesea but we used classical DRM paradigm like Roediger. Experiment 1 replicates the DRM effect. Experiment 2 & 3 shows that the DRM effect is decreased but not abolished when participants are prevented from being surprised by critical word. It is proposed that experience of surprise participate to DRM effect, but not alone. [less ▲]

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See detailThe Mere Exposure Effects Depends on the Way You Look!
Willems, Sylvie ULg; Dedonder, Jonathan

Poster (2008, May)

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See detailThe use of perceptual fluency in patients with Alzheimer disease: the role of expectation
Willems, Sylvie ULg; Van der Linden, Martial ULg

in Journal of Cognitive Neuroscience (2008, April)

We investigated whether the use of perceptual fluency as recognition cue by patients with Alzheimer disease (AD) depends on whether fluency is perceived as relevant to the recognition decision. In normal ... [more ▼]

We investigated whether the use of perceptual fluency as recognition cue by patients with Alzheimer disease (AD) depends on whether fluency is perceived as relevant to the recognition decision. In normal subjects, enhanced perceptual fluency increased positive recognition responses when study and test stimuli were presented in the same sensory modality but not when stimuli were presented in different modalities (Westerman et al., J. of Mem. & Lang., 47, 2002). These results suggest that the use of perceptual fluency as a heuristic in recognition memory depends on the correspondence between study and test modalities and thus on the perceived usefulness of fluency. We investigated this change of sensory modality between study and test phases in 16 AD patients and 16 matched normal controls by using a verbal recognition task. The perceptual fluency of recognition test items was enhanced by briefly presenting a prime that matched the subsequent test item. We observed that changes in modality attenuated the contribution of fluency to the recognition decision in both subjects groups. In addition, we noted a positive correlation between fluency use and metamemory self-evaluation. These results suggest that the fluency heuristic is subject to metacognitive control in AD patients, exactly in the same way as normal subject, since patients’ attributions of perceptual fluency depend on expectations about relevance of fluency as memory cue. [less ▲]

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See detailImplicit/explicit memory dissociation in Alzheimer's disease: the consequence of inappropriate processing?
Willems, Sylvie ULg; Salmon, Eric ULg; Van der Linden, Martial ULg

in Neuropsychology (2008), 22(6), 710-7

Dual-process theories of recognition posit that perceptual fluency contributes to both familiarity-based explicit recognition and perceptual priming. However, the priming-without-recognition dissociation ... [more ▼]

Dual-process theories of recognition posit that perceptual fluency contributes to both familiarity-based explicit recognition and perceptual priming. However, the priming-without-recognition dissociation, as observed through the intact mere exposure effect and impaired recognition in patients with Alzheimer's disease (AD), might indicate that familiarity and perceptual priming are functionally distinct. This study investigated whether the AD patients' processing strategies at testing may explain this priming-without-recognition dissociation. First, we replicated the priming-without-recognition effect in 16 patients who exhibited intact exposure effects despite null recognition. Second, we showed that, under identical conditions, inducing a holistic processing strategy during recognition testing increased AD patients' recognition--performance was similar for AD patients and healthy control participants. Furthermore, prompting analytic processing during both priming and recognition tasks decreased AD patients' performance in both tasks. These findings suggest that the extent to which AD patients use perceptual fluency in priming and recognition tasks is contingent on their processing approach. The choice of processing strategy may depend on how difficult patients perceive the task to be. [less ▲]

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See detailExperimental dissociations between memory measures: Influence of retrieval strategies.
Willems, Sylvie ULg; Van der Linden, Martial

in Consciousness & Cognition (2008)

The objective of this study was to explore the participants' processing strategies on the mere exposure effect, object decision priming and explicit recognition. In Experiments 1, we observed that ... [more ▼]

The objective of this study was to explore the participants' processing strategies on the mere exposure effect, object decision priming and explicit recognition. In Experiments 1, we observed that recognition and the mere exposure effect for unfamiliar three-dimensional objects were not dissociated by plane rotations in the same way as recognition and object decision priming. However, we showed that, under identical conditions, prompting analytic (part-based) processing at testing produced a large plane rotation effect on recognition and the mere exposure effect similar to that observed for object decision priming (Experiment 2). Furthermore, inducing a non-analytic (whole-based) processing strategy at testing produced a reduced plane rotation effect on recognition and object decision (Experiments 3 and 4), similar to that observed for the mere exposure effect. These findings suggest that participants' processing strategies influence performance on the three tasks. [less ▲]

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See detailWhat is the impact of the explicit knowledge of sequence regularities on both deterministic and probabilistic serial reaction time task performance?
Stefaniak, Nicolas ULg; Willems, Sylvie ULg; Adam, Stéphane ULg et al

in Memory & Cognition (2008), 36(7), 1283-98

The aim of this study was to explore the role of prior explicit sequence knowledge by comparing its influence on serial reaction time (SRT) performance with either a deterministic or a probabilistic ... [more ▼]

The aim of this study was to explore the role of prior explicit sequence knowledge by comparing its influence on serial reaction time (SRT) performance with either a deterministic or a probabilistic sequence. The results confirm that, with a deterministic sequence, preliminary explicit learning improves SRT performance. On the other hand, with a probabilistic sequence, the results show no advantage for SRT performance in explicit-learning conditions. In addition, by using the process dissociation procedure (Jacoby, 1991), we show that performance on a subsequent generation task was more sustained by controlled processes for participants in the explicit-learning conditions than for those in the incidental condition. On the whole, these results, showing that the influence of explicit knowledge can be suppressed in certain specific conditions, are consistent with the intervention of both implicit and explicit mechanisms in SRT tasks, and the results also show that their relative influence can be modulated by the particular demands of the task. [less ▲]

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See detailCerebral asymmetries in sleep-dependent processes of memory consolidation
Peigneux, Philippe ULg; Schmitz, Remy; Willems, Sylvie ULg

in Learning & Memory (2007), 14(6), 400-406

Preference for previously seen, unfamiliar objects reflects a memory bias on affective judgment, known as the "mere exposure effect" (MEE). Here, we investigated the effect of time, post-exposure sleep ... [more ▼]

Preference for previously seen, unfamiliar objects reflects a memory bias on affective judgment, known as the "mere exposure effect" (MEE). Here, we investigated the effect of time, post-exposure sleep, and the brain hemisphere solicited on preference generalization toward objects viewed in different perspectives. When presented in the right visual field (RVF), which promotes preferential processing in the left hemisphere, same and mirrored exemplars were preferred immediately after exposure. MEE generalized to much dissimilar views after three nights of sleep. Conversely, object presentation in the left visual field (LVF), promoting right hemisphere processing, elicited a MEE for same views immediately after exposure, then for mirror views after sleep. Most importantly, sleep deprivation during the first post-exposure night, although followed by two recovery nights, extinguished MEE for all views in the LVF but not in the RVF. Besides demonstrating that post-exposure time and sleep facilitate the generalization process by which we integrate various representations of an object, our results suggest that mostly in the right hemisphere, sleep may be mandatory to consolidate the memory bias underlying affective preference. These interhemispheric differences tentatively call for a reappraisal of the role of cerebral asymmetries in wake- and sleep-dependent processes of memory consolidation. [less ▲]

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See detailThe contribution of processing fluency to preference : a comparison with familiarity-based recognition
Willems, Sylvie ULg; Van der Linden, Martial ULg; Bastin, Christine ULg

in European Journal of Cognitive Psychology (2007), 19(1), 119-140

There is a great deal of evidence supporting the idea that, when a stimulus is processed fluently, it is more likely to be judged as pleasant. However, this influence of fluency on preference judgement ... [more ▼]

There is a great deal of evidence supporting the idea that, when a stimulus is processed fluently, it is more likely to be judged as pleasant. However, this influence of fluency on preference judgement seems to depend on several experimental conditions. So we tried to better understand these conditions via a comparison with recognition and by manipulating some aspects of the procedure (test format) and material (similarity and figure-ground contrast of the stimuli). Two experiments showed that some conditions maximally induce the use of processing fluency in a preference judgement, as in a recognition task. We discuss the implications of these findings for the well-documented discrepancy-attribution hypothesis (Whittlesea [less ▲]

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See detailMere exposure effect : a consequence of direct and indirect fluency-preference links
Willems, Sylvie ULg; Van der Linden, Martial ULg

in Consciousness & Cognition (2006), 15(2), 323-341

In three experiments, picture quality between test items was manipulated to examine whether subjects' expectations about the fluency normally associated with these different stimuli might influence the ... [more ▼]

In three experiments, picture quality between test items was manipulated to examine whether subjects' expectations about the fluency normally associated with these different stimuli might influence the effects of fluency on preference or familiarity-basea recognition responses. The results showed that fluency due to pre-exposure influenced responses less when objects were presented with high picture quality, suggesting that attributions of fluency to preference and familiarity are adjusted according to expectations about the different test pictures. However, this expectations influence depended on subjects' awareness of these different quality levels. Indeed, imperceptible differences seemed not to induce expectations about the test item fluency. In this context, fluency due to both picture quality and pre-exposure influenced direct responses. Conversely, obvious, and noticed, differences in test picture quality did no affect responses, suggesting that expectations moderated attributions of fluency only when fluency normally associated with these different stimuli was perceptible but difficult to assess. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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See detailImplicit memory during isoflurane anesthesia
Iselin-Chaves, Irène; Willems, Sylvie ULg

in Anesthesiology (2006), 105

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See detailA French adaptation of the UPPS Impulsive Behavior Scale: Confirmatory factor analysis in a sample of undergraduate students
Van der Linden, Martial ULg; d'Acremont, M.; Zermatten, A. et al

in European Journal of Psychological Assessment (2006), 22(1), 38-42

Impulsivity is an important and multifaceted psychological construct. Recently, Whiteside and Lynam (2001) have developed the UPPS Impulsive Behavior Scale that distinguishes four dimensions of ... [more ▼]

Impulsivity is an important and multifaceted psychological construct. Recently, Whiteside and Lynam (2001) have developed the UPPS Impulsive Behavior Scale that distinguishes four dimensions of impulsivity: Urgency, lack of Premeditation, lack of Perseverance, and Sensation seeking. In the present study, we investigated the psychometric properties of a French adaptation of the UPPS Impulsive Behavior Scale. Two hundred and thirty-four undergraduate students completed the UPPS Scale. Exploratory and confirmatory analyses revealed a four factors solution similar to that found in the original study. Also, the results indicated that there was good to very good internal reliability for the four subscales. [less ▲]

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See detailImplicit memory during isoflurane anesthesia - Reply
Iselin-Chaves, Irène A.; Willems, Sylvie ULg

in Anesthesiology (2006), 105(2), 430-430

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See detailL'effet de simple exposition : approche cognitive et neuropsychologique
Willems, Sylvie ULg

Doctoral thesis (2005)

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See detailInvestigation of automatic memory during general anesthesia for elective surgery using the process dissociation procedure
Willems, Sylvie ULg; Iselin-Chaves, Irène A.; Jermann, Françoise J. et al

in Anesthesiology (2005), 103

Background: This prospective study evaluated memory function during general anesthesia for elective surgery and its relation to depth of hypnotic state. The authors also compared memory function in ... [more ▼]

Background: This prospective study evaluated memory function during general anesthesia for elective surgery and its relation to depth of hypnotic state. The authors also compared memory function in anesthetized and nonanesthetized subjects. Methods: Words were played for 70 min via headphones to 48 patients (aged 18–70 yr) after induction of general anesthesia for elective surgery. Patients were unpremedicated, and the anesthetic regimen was free. The Bispectral Index (BIS) was recorded throughout the study. Within 36 h after the word presentation, memory was assessed using an auditory word stem completion test with inclusion and exclusion instructions. Memory performance and the contribution of explicit and implicit memory were calculated using the process dissociation procedure. The authors applied the same memory task to a control group of nonanesthetized subjects. Results: Forty-seven patients received isoflurane, and one patient received propofol for anesthesia. The mean ( SD) BIS was 49 9. There was evidence of memory for words presented during light (BIS 61–80) and adequate anesthesia (BIS 41–60) but not during deep anesthesia (BIS 21–40). The process dissociation procedure showed a significant implicit memory contribution but not reliable explicit memory contribution (mean explicit memory scores 0.05 0.14, 0.04 0.09, and 0.05 0.14; mean automatic influence scores 0.14 0.12, 0.17 0.17, and 0.18 0.21 at BIS 21–40, 41–60, and 61–80, respectively). Compared with anesthetized patients, the memory performance of nonanesthetized subjects was better, with a higher contribution by explicit memory and a comparable contribution by implicit memory. Conclusion: During general anesthesia for elective surgery, implicit memory persists even in adequate hypnotic states, to a comparable degree as in nonanesthetized subjects. [less ▲]

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See detailL'effet de simple exposition : un simple amorçage?
Willems, Sylvie ULg

Scientific conference (2004, May)

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See detailDifférences interindividuelles dans la propension aux faux souvenirs
Willems, Sylvie ULg; Van der Linden, Martial ULg

in Brédart, Serge (Ed.) Souvenirs récupérés, souvenirs oubliés et faux souvenirs (2004)

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See detailSensation-seeking and impulsivity in young and older adults' decision making
Willems, Sylvie ULg; Van der Linden, Martial ULg; Marczewski, Philippe

in Brain & Cognition (2003), 51(2), 237-239

The somatic marker hypothesis asserts that decision-making processes involve emotion. Using a gambling task that models real-life decisions, studies showed that old adults perform less efficiently than ... [more ▼]

The somatic marker hypothesis asserts that decision-making processes involve emotion. Using a gambling task that models real-life decisions, studies showed that old adults perform less efficiently than younger adults, by adopting a strategy that is disadvantageous on the long term. This study aimed at re-examining the age effect on decisionmaking with the same paradigm, and to explore whether differences are related to sensation-seeking and impulsivity traits of personality. Young and older adults were compared on the gambling task (Bechara, Damasio, & Damasio, 2000a), and on questionnaires of sensationseeking and impulsivity. Results confirmed an age effect on the gambling task performance. Moreover, performance in both young and older adults on this task was correlated to scores on the sensation-seeking scale, but not to the rating of impulsivity [less ▲]

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