Timo Giesbrecht

Timo Giesbrecht
Unilever · Beauty & Personal Care Science & Technology

PhD

About

104
Publications
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3,010
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Publications

Publications (104)
Article
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Online retailers often sell products using a socially competitive second-price sealed-bid auction known as a Vickrey auction (VA), an incentivized demand-revealing mechanism used to elicit players' subjective values. The VA presents a situation of risky decision-making, which typically implements value processing and a loss aversion mechanism. Neur...
Article
Previous studies have shown attenuation of cortical oscillations over bilateral sensorimotor cortex areas during passive perception of smooth textures applied to the skin. However, humans typically explore surfaces using dynamic hand movements. As movements may both modulate texture-related cortical activity and induce movement-related cortical act...
Chapter
Up to now, the neurobiological underpinnings of how decision-makers assign and compare alternatives during choice have been studied under highly controlled laboratory conditions. Hence, it is unclear how well these findings translate to decision-making in naturalistic settings. This chapter addresses the theoretical and methodological aspects of th...
Article
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Losses usually have greater subjective value (SV) than gains of equal nominal value but often cause a relative deterioration in effortful performance. Since losses and gains induce differing approach/avoidance behavioral tendencies, we explored whether incentive type interacted with approach/avoidance motor-sets. Alpha- and beta-band event-related...
Article
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Congruent visual cues augment sensitivity to brief olfactory presentations and habituation of odor perception is modulated by central-cognitive processing including context. However, it is not known whether habituation to odors could interact with cross-modal congruent stimuli. The present research investigated the effect of visual congruence on od...
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We explored how reward and value of effort shapes performance in a sustained vigilance, reaction time (RT) task. It was posited that reward and value would hasten RTs and increase cognitive effort by boosting activation in the sensorimotor cortex and inhibition in the frontal cortex, similar to the horse-race model of motor actions. Participants pe...
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Background: The reward value of palatable foods is often cited as an important influence on eating behaviors, including intake of sugars. However, human neuroimaging studies have generated conflicting evidence on the basic neural representation of taste and reward responses to caloric sweeteners (sucrose and glucose), and most relevant studies hav...
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Values are attributed to goods during free viewing of objects which entails multi- and trans-saccadic cognitive processes. Using electroencephalographic eye-fixation related potentials, the present study investigated how neural signals related to value-guided choice evolved over time when viewing household and office products during an auction task...
Article
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Economic decision making refers to the process of individuals translating their preference into subjective value (SV). Little is known about the dynamics of the neural processes that underpin this form of value-based decision making and no studies have investigated these processes outside of controlled laboratory settings. The current study investi...
Article
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Expectations can affect subjective sensory and hedonic ratings of tastes, but it is unclear whether they also shape sensory experience at a perceptual level. The neural correlates of the taste‐expectancy relationship were explored through EEG analysis. Using a trial‐by‐trial cueing paradigm, lingual delivery of 0.05 M or 0.3 M sucrose solutions was...
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The detection of a human face in a visual field and correct reading of emotional expression of faces are important elements in everyday social interactions, decision making and emotional responses. Although brain correlates of face processing have been established in previous fMRI and electroencephalography (EEG)/MEG studies, little is known about...
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Implicit attentional processes are biased toward food-related stimuli, with the extent of that bias reflecting relative motivation to eat. These interactions have typically been investigated by comparisons between fasted and sated individuals. In this study, temporal changes in implicit attention to food were assessed in relation to natural, sponta...
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Subjective and behavioral responsiveness to odor diminishes during prolonged exposure. The precise mechanisms underlying olfactory desensitization are not fully understood, but previous studies indicate that the phenomenon may be modulated by central-cognitive processes. The present study investigated the effect of attention on perceived intensity...
Article
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The value of environmental cues and internal states is continuously evaluated by the human brain and it is this subjective value that largely guides decision-making. The present study aimed to investigate the initial value attribution process, specifically the spatio-temporal activation patterns associated with values and valuation context using el...
Article
Odours alter evaluations of concurrently presented visual stimuli, such as faces. Stimulus onset asynchrony (SOA) is known to affect evaluative priming in various sensory modalities. However, effects of SOA on odour priming of visual stimuli are not known. The present study aimed to analyse whether subjective and cortical activation changes during...
Article
Thermal tasters (TTs) perceive thermally induced taste (thermal taste) sensations when the tongue is stimulated with temperature in the absence of gustatory stimuli, while thermal non tasters (TnTs) only perceive temperature. This is the first study to explore detailed differences in thermal taste responses across TTs. Using thermal taster status p...
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Determination of the number of fungiform papillae (FP) on the human tongue is an important measure that has frequently been associated with individual differences in oral perception, including taste sensitivity. At present, there is no standardised method consistently used to identify the number of FP, and primarily scientists manually count papill...
Article
Objectives Previous neuroimaging studies have shown face-specific neural responses to faces compared to objects. The detection of face-specific brain activation in freely behaving and moving people has yet to be accomplished. The purpose of our research was to identify, using wireless multichannel EEG in freely moving participants, eye movement rel...
Article
Odours alter evaluations of concurrent visual stimuli. However, neural mechanisms underlying the effects of congruent and incongruent odours on facial expression perception are not clear. Moreover, the influence of emotional faces on odour perception is not established. We investigated the effects of one pleasant and one unpleasant odour paired wit...
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Background: We investigated whether substituting sitting with standing and self-perceived light walking in free-living conditions would improve cardiometabolic risk factors, mood, and cognition in overweight/obese adults. Methods: In a randomized, cross-over study, 24 (m/f: 13/11) sedentary overweight/obese participants (64 ± 7 years, BMI 29 ± 2 kg...
Article
Loss aversion is the tendency to prefer avoiding losses over acquiring gains of the same amount. To shed light on the spatio-temporal processes underlying loss aversion, we analysed the associations between individual loss aversion and electrophysiological responses to loss and gain outcomes in a monetary gamble task. Electroencephalographic feedba...
Article
We present an overview of major dissociative disorders, including depersonalization/derealization disorder, dissociative amnesia, and dissociative identity disorder. We discuss the prevalence, etiology, and treatment of each disorder and review treatment approaches. We present two competing models of dissociation – the posttraumatic model and the s...
Article
Past research has established clear support for the prosocial function of gratitude in improving the well-being of others. The present research provides evidence for another hypothesized function of gratitude: the social alignment function, which enhances the tendency of grateful individuals to follow social norms. We tested the social alignment hy...
Article
Tea has historically been associated with mood benefits. Nevertheless, few studies have empirically investigated mood changes after tea consumption. We explored immediate effects of a single cup of tea up to an hour post-consumption on self-reported valence, arousal, discrete emotions, and implicit measures of mood. In a parallel group design, 153...
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Insula cortex and hypothalamus are implicated in eating behaviour, and contain receptor sites for peptides and hormones controlling energy balance. Insula encompasses multi-functional subregions, which display differential anatomical and functional connectivities with the rest of the brain. The study aimed to analyse the effect of fasting and satia...
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Odors can alter hedonic evaluations of human faces, but the neural mechanisms of such effects are poorly understood. The present study aimed to analyze the neural underpinning of odor-induced changes in evaluations of human faces in an odor-priming paradigm, using event-related potentials (ERPs). Healthy, young participants (N = 20) rated neutral f...
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Background and Objectives: The potential link between dissociative symptoms and symptom over-reporting has been given little attention. In two student samples (N’s = 139 and 113) and a clinical sample (N = 21), we examined whether self-reported dissociative symptoms are related to symptom over-reporting. Methods: We relied on different measures of...
Article
Some drugs of abuse may produce dissociative symptoms, but this aspect has been understudied. We explored the dissociative potential of three recreational drugs (3,4-methylenedioxymethamphetamine (MDMA), cannabis, and cocaine) during intoxication and compared their effects to literature reports of dissociative states in various samples. Two placebo...
Chapter
Major dissociative disorders in DSM-5 include dissociative amnesia, depersonalization/derealization disorder, and dissociative identity disorder. The trauma model and the sociocognitive model are two perspectives that vie for empirical support as explanations of the genesis of dissociative identity disorder and perhaps other dissociative disorders....
Chapter
Depersonalization is marked by persistent or recurring symptoms, including perceptual alterations, distorted sense of time, feeling as though one is an outside observer of one's body, or feeling like an automaton or like one is living in a dream or a movie. These symptoms are often accompanied by derealization, the feeling that the world, oneself,...
Article
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Hunger and pain are basic drives that compete for a behavioral response when experienced together. To investigate the cortical processes underlying hunger-pain interactions, we manipulated participants' hunger and presented photographs of appetizing food or inedible objects in combination with painful laser stimuli. Fourteen healthy participants co...
Article
Because of their dreamlike character, authors have speculated about the role that the sleep-wake cycle plays in dissociative symptoms. We investigated whether sleep loss fuels dissociative symptoms and undermines cognitive efficiency, particularly memory functioning. Fifty-six healthy undergraduate students were randomly assigned to an experimental...
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Sleep disturbances, fantasy proneness, cognitive failures, and dissociative symptoms are related to each other. However, the co-occurrence of these phenomena has been primarily studied in non-clinical samples. We investigated the correlations between these phenomena in dissociative identity disorder (DID) patients, post-traumatic stress disorder (P...
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Dalenberg et al. (2012) argued that convincing evidence (a) supports the longstanding trauma model (TM), which posits that early trauma plays a key role in the genesis of dissociation; and (b) refutes the fantasy model (FM), which posits that fantasy proneness, suggestibility, cognitive failures, and other variables foster dissociation. We review e...
Article
Evidence suggests that asymmetry in frontal electrical activity predicts responses to aversive experiences, such that higher left-sided activity might dampen responses to trauma reminders. We measured frontal asymmetry at rest and during viewing of a trauma film, and assessed startle responses to film-reminder images. To explore potential moderator...
Article
Background: Dissociative disorders encompass a range of symptoms varying from severe absent-mindedness and memory problems to confusion about one's own identity. Recent studies suggest that these symptoms may be the by-products of a labile sleep-wake cycle. Methods: In the current study, we explored this issue in patients suffering from insomnia...
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Stress and stress hormones modulate memory formation in various ways that are relevant to our understanding of stress-related psychopathology, such as posttraumatic stress disorder (PTSD). Particular relevance is attributed to efficient memory formation sustained by the hippocampus and parahippocampus. This process is thought to reduce the occurren...
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Rationale Despite the large number of studies on the behavioural effects of caffeine, an unequivocal conclusion had not been reached. In this review, we seek to disentangle a number of questions. Objective Whereas there is a general consensus that caffeine can improve performance on simple tasks, it is not clear whether complex tasks are also affec...
Article
Emotional stimuli draw attention to such an extent that they hamper the processing of subsequent signals, a phenomenon termed emotion-induced blindness (EIB). As depersonalization is associated with self-reported attenuated emotional responses, the present study explored whether individuals scoring high on the Cambridge Depersonalization Scale (CDS...
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The dual-representation model of posttraumatic stress disorder (PTSD; Brewin, Gregory, Lipton, & Burgess, Psychological Review, 117, 210-232 2010) argues that intrusions occur when people fail to construct context-based representations during adverse experiences. The present study tested a specific prediction flowing from this model. In particular,...
Article
A widespread assumption in research and clinical practice is that cognitive reappraisal is a healthy and successful emotion regulation strategy, while expressive suppression is ineffective and has non-favourable consequences (e.g., decreased positive affect, higher physiological arousal). However, little is known about the consequences of reapprais...
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In psychopathology, dissociation typically refers to a disturbance in the normal integration of thoughts, feelings, and experiences into consciousness and memory. In this article, we review the literature on how sleep disturbances relate to dissociative symptoms and memory failure. We contend that this body of research offers a fresh perspective on...
Article
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Conventional wisdom holds that dissociation is a coping mechanism triggered by exposure to intense stressors. Drawing on recent research from multiple laboratories, we challenge this prevailing posttraumatic model of dissociation and dissociative disorders. Proponents of this model hold that dissociation and dissociative disorders are associated wi...
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We conducted a longitudinal study to investigate the relation between sleep experiences and dissociative symptoms in a mixed inpatient sample at a private clinic evaluated on arrival and at discharge 6 to 8 weeks later. Using hierarchical regression analyses and structural equation modeling, we found a link between sleep experiences and dissociativ...
Article
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Serotonin synthesis critically depends on plasma levels of tryptophan (TRP). Earlier studies have shown that for mood and cognitive benefits to occur, the ratio between TRP and other large neutral amino acids (LNAA) has to be increased by approximately 40 %. The present study investigated the dose-dependent effects of a TRP-rich hydrolysed protein...
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In laboratory studies, sleepiness has been found to increase dissociative symptoms. To explore the link between sleepiness and dissociation in a natural setting. A longitudinal study was performed among volunteers at a pop festival. Information was collected via self-report scales at four successive test moments spread over a 12-hour period. Sleepi...
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The non-proteinic amino acid L-theanine and caffeine, a methylxanthine derivative, are naturally occurring ingredients in tea. The present study investigated the effect of a combination of 97 mg L-theanine and 40 mg caffeine as compared to placebo treatment on cognitive performance, alertness, blood pressure, and heart rate in a sample of young adu...
Article
It is often assumed that when confronted with an emotional event, patients with DPD inhibit information processing. It is also thought that this fosters memory fragmentation. This hypothesis has not been tested in chronic depersonalization. The aim of this study was to investigate the temporal pattern of autonomic responding to emotional material i...
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In a recent review (see record 2008-11487-001), we critically evaluated the research literature on cognitive processes in dissociation. In a comment, Bremner (see record 2009-24669-001) has voiced reservations about our contention that evidence for the causal role of trauma in dissociation is limited. In this reply, we argue that Bremner’s argume...
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De dissociatieve stoornis NAO maakt samen met de dissociatieve identiteitsstoornis , de dissociatieve amnesie , de dissociatieve fugue , en de depersonalisatiestoornis deel uit van de dissociatieve stoornissen zoals die worden beschreven in het Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR; American Psychiatric Association, 2000)...
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A substantial proportion of psychiatric research is based on surveys that rely on self-report scales. Little is known about careless respondents in such surveys. To explore to what extent careless respondents may bias the outcomes of surveys. Three surveys were conducted among paid volunteers (undergraduates). A small but non-trivial proportion of...
Article
We explored whether children's suggestion-induced omission errors are caused by memory erasure. Seventy-five children were instructed to remove three pieces of clothing from a puppet. Next, they were confronted with evidence falsely suggesting that one of the items had not been removed. During two subsequent interviews separated by one week, childr...
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According to betrayal trauma theory, many survivors of childhood sexual abuse learn to compartmentalize (i.e., dissociate) their traumatic experiences from conscious awareness by dividing attention. This theory predicts that those who dissociate extensively should be at an advantage during dual tasks. Using a modified Stroop task in Experiment 1 an...
Article
Alexithymia, absorption, and cognitive failures are traits that have been implicated in dissociative psychopathology. Forty-six participants with depersonalization disorder (DPD), 21 with posttraumatic stress disorder, and 35 healthy controls completed measures of dissociation, alexithymia, absorption, cognitive failures, and childhood trauma. The...