Florian Lange - Academia.edu (original) (raw)

Papers by Florian Lange

Human Nature, 2015

Numerous laboratory experiments suggest that mechanisms of indirect reciprocity might account for... more Numerous laboratory experiments suggest that mechanisms of indirect reciprocity might account for human cooperation. However, conclusive field data supporting the predictions of indirect reciprocity in everyday life situations is still scarce. Here, we attempt to compensate for this lack by examining the determinants of cooperative behavior in a German supermarket. Our methods were as follows: Confederates of the experimenter lined up at the checkout, apparently to buy a single item. As an act of cooperation, the waiting person in front (the potential helper) could allow the confederate to go ahead. By this means, the potential helper could take a cost (additional waiting time) by providing the confederate with a benefit (saved waiting time). We recorded the potential helpers' behavior and the number of items they purchased as a quantitative measure proportional to the confederate's benefit. Moreover, in a field experimental design, we varied the confederates' image by manipulating the item they purchased (beer vs. water). As predicted, the more waiting time they could save, the more likely the confederates were to receive cooperation. This relationship was moderated by the confederates' image. Cost-to-benefit ratios were required to be more favorable for beer-purchasing individuals to receive cooperation. Our results demonstrate that everyday human cooperation can be studied unobtrusively in the field and that cooperation among strangers is selective in a way that is consistent with current models of indirect reciprocity.

Neuroscience & Biobehavioral Reviews, 2016

Cognitive impairment is a common non-motor symptom of Parkinson's... more Cognitive impairment is a common non-motor symptom of Parkinson's disease (PD), but the nature of cognitive changes varies considerably between individuals. According to the dual-syndrome hypothesis, one cluster of patients is characterized by deficits in executive function that may be related to fronto-striatal dysfunction. Other patients primarily show non-frontal cognitive impairments that progress rapidly to PD dementia (PDD). We provide a comprehensive review of event-related potential (ERP) studies to identify ERP measures substantiating the heterogeneity of cognitive impairment in PD. Our review revealed evidence for P3b and mismatch-negativity alterations in PDD, but not in non-demented PD, indicating that alterations of these ERPs constitute electrophysiological markers for PDD. In contrast, ERP correlates of executive functions, such as NoGo-P3, N2 and error(-related) negativity (Ne/ERN), appear to be attenuated in non-demented PD patients in a dopamine-dependent manner. Hence, ERP measures confirm and yield distinct electrophysiological markers for the heterogeneity of cognitive impairment in PD. We discuss limitations and open questions of the ERP approach and provide directions and predictions for future ERP research.

Brain, 1995

Activity of the supplementary motor area may be inferred from movement-related potentials (MRPs) ... more Activity of the supplementary motor area may be inferred from movement-related potentials (MRPs) which are associated with the preparation and execution of voluntary, or internally determined movements. Supplementary motor area activity may be abnormal in Parkinson's disease since its major input from the basal ganglia is disrupted. Investigation of the abnormalities in supplementary motor area activity associated with movement deficits in Parkinson's disease may therefore reveal functions of the basal ganglia and the supplementary motor area. Movement-related potentials associated with sequential movements were investigated under various cueing conditions in Parkinson's disease subjects and age-matched controls. In controls, MRPs revealed involvement of the supplementary motor area in movements which can be internally determined (non-cued and externally cued, predictable movements, but not unpredictable movements). In Parkinson's disease, however, the supplementary motor area was only involved in movements which must be internally determined (non-cued movements, but not externally cued movements); therefore impaired internal control mechanisms, operating via the supplementary motor area, are bypassed when external cues are given. As a result, Parkinson's disease patients are more reliant on external cues and are unable to use predictive models to internally guide movement. Supplementary motor area involvement also relied on the predictability (in controls) or presence (in Parkinson's disease) of timing cues and not spatial cues, indicating a role of the supplementary motor area and basal ganglia in the temporal organizations of sequential movement rather than the programming of specific movements. For non-cued movements, abnormalities in MRPs for Parkinson's disease subjects consisted of delayed MRP onset and peak times, and prolonged cortical activity following movement. These observations led to a proposed model of the interaction between the basal ganglia and the supplementary motor area, involving the temporal organization of voluntary and internally determined sequential movements.

Clinical Neurophysiology, 2016

Amyotrophic lateral sclerosis (ALS) has been associated with executive dysfunction, particularly ... more Amyotrophic lateral sclerosis (ALS) has been associated with executive dysfunction, particularly in the domain of cognitive set shifting. In a recent event-related potential (ERP) study, shifting-related cortical activity on a complex set-shifting paradigm was found to be attenuated in patients with ALS. Here, we investigated whether this ERP change could also be observed in a simplified set-shifting task adapted for potential clinical use, and in ALS patients without overt cognitive impairment. Twenty-six patients and 28 matched healthy controls (HC) completed a set-shifting paradigm involving two task rules and explicit task cues. Cue-locked ERPs were analyzed. ALS patients and HC did not differ in response latency or accuracy. In HC, cues that required shifting task rules elicited more positive parietal ERP waveforms than cues that signaled a rule repetition. This shifting-related amplitude modulation was absent in patients with ALS. The attenuation of ERP activity in ALS patients remained significant when participants with possible cognitive impairment were excluded. Electrophysiological measures can detect ALS-related changes in the neural substrates of set shifting even when these changes do not become apparent in neuropsychological assessment. These findings illustrate the potential utility of ERPs as indicators of cognitive change in ALS.

Accident; analysis and prevention, 2016

A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road ... more A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road illegally. In a recent analysis, illegal road crossing behavior has been shown to be enhanced in the presence of incongruent stimulus configurations. Pedestrians and cyclists are more likely to cross against a red light when exposed to an irrelevant conflicting green light. Here, we present experimental and observational data on the factors moderating the risk associated with incongruent traffic lights. In an observational study, we demonstrated that the conflict-related increase in illegal crossing rates is reduced when pedestrian and cyclist green light periods are long. In a laboratory experiment, we manipulated the color of the irrelevant signals to expose participants to different degrees of incongruency. Results revealed that individuals' performance gradually varied as a function of incongruency, suggesting that the negative impact of a conflicting green light can be reduced b...

Cognitive, Affective, & Behavioral Neuroscience, 2016

The capability of the human brain for Bayesian inference was assessed by manipulating probabilist... more The capability of the human brain for Bayesian inference was assessed by manipulating probabilistic contingencies in an urn-ball task. Event-related potentials (ERPs) were recorded in response to stimuli that differed in their relative frequency of occurrence (.18 to .82). A veraged ERPs with sufficient signal-to-noise ratio (relative frequency of occurrence > .5) were used for further analysis. Research hypotheses about relationships between probabilistic contingencies and ERP amplitude variations were formalized as (in-)equality constrained hypotheses. Conducting Bayesian model comparisons, we found that manipulations of prior probabilities and likelihoods were associated with separately modifiable and distinct ERP responses. P3a amplitudes were sensitive to the degree of prior certainty such that higher prior probabilities were related to larger frontally distributed P3a waves. P3b amplitudes were sensitive to the degree of likelihood certainty such that lower likelihoods were associated with larger parietally distributed P3b waves. These ERP data suggest that these antecedents of Bayesian inference (prior probabilities and likelihoods) are coded by the human brain.

Journal of the International Neuropsychological Society : JINS, 2016

Objectives Although primary dystonia is typically characterized as a movement disorder, it is als... more Objectives Although primary dystonia is typically characterized as a movement disorder, it is also associated with cognitive alterations in the domain of executive functioning which may arise from changes in cortico-basal ganglia circuits. Specifically, in comparison to healthy controls, patients with dystonia show deficits in neuropsychological tests of cognitive flexibility. However, it is unclear whether cognitive inflexibility is caused by the pathomechanisms underlying primary dystonia or by confounding factors such as depression or symptom-related distraction.Methods The present study aimed to eliminate these confounds by examining cognitive flexibility in dystonia patients and in patients with similar motor symptoms but without a comparable central pathophysiology. Eighteen patients with primary blepharospasm, a common form of dystonia affecting the muscles around the eyes, and 19 patients with hemifacial spasm, a facial nerve disorder causing similar eyelid spasms, completed...

Cortex; a journal devoted to the study of the nervous system and behavior, Jan 8, 2016

Impaired motor control in primary dystonia has been linked to cortico-basal ganglia alterations t... more Impaired motor control in primary dystonia has been linked to cortico-basal ganglia alterations that may also give rise to changes in executive functioning. However, no conclusive evidence for executive dysfunction in patients with primary dystonia has been reported yet. We conducted a meta-analysis of the relationship between primary dystonia and performance on the Wisconsin Card Sorting Test (WCST), an established test of executive functioning. Its results revealed a significant effect of medium size, indicating that primary dystonia is associated with moderate performance deficits on the WCST. Building on this finding, we conducted an event-related potential (ERP) study to elucidate the cognitive and neural mechanisms underlying executive dysfunction in primary dystonia. Eighteen patients with blepharospasm, a common form of primary focal dystonia, and 34 healthy matched controls completed a computerized version of the WCST. We specifically compared indicators of two distinct com...

Brain and Cognition, 2016

The human brain predicts events in its environment based on expectations, and unexpected events a... more The human brain predicts events in its environment based on expectations, and unexpected events are surprising. When probabilistic contingencies in the environment are precisely instructed, the individual can form expectations based on quantitative probabilistic information ('inference-based learning'). In contrast, when probabilistic contingencies are imprecisely instructed, expectations are formed based on the individual's cumulative experience ('experience-based learning'). Here, we used the urn-ball paradigm to investigate how variations in prior probabilities and in the precision of information about these priors modulate choice behavior and event-related potential (ERP) correlates of surprise. In the urn-ball paradigm, participants are repeatedly forced to infer hidden states responsible for generating observable events, given small samples of factual observations. We manipulated prior probabilities of the states, and we rendered the priors calculable or incalculable, respectively. The analysis of choice behavior revealed that the tendency to consider prior probabilities when making decisions about hidden states was stronger when prior probabilities were calculable, at least in some of our participants. Surprise-related P3b amplitudes were observed in both the calculable and the incalculable prior probability condition. In contrast, calculability of prior probabilities modulated anteriorly distributed ERP amplitudes: when prior probabilities were calculable, surprising events elicited enhanced P3a amplitudes. However, when prior probabilities were incalculable, surprise was associated with enhanced N2 amplitudes. Furthermore, interindividual variability in reliance on prior probabilities was associated with attenuated P3b surprise responses under calculable in comparison to incalculable prior probabilities. Our results suggest two distinct neural systems for probabilistic learning that are recruited depending on contextual cues such as the precision of probabilistic information. Individuals with stronger tendencies to rely on calculable prior probabilities seem to have better adapted expectations at their disposal, as indicated by an attenuation of their P3b surprise responses when prior probabilities are calculable.

Frontiers in Psychology, 2016

Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian model... more Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modeling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities) by two (likelihoods) design. Five computational models of cognitive processes were compared with the observed behavior. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted) S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model's success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modeling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modeling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision.

Neuropsychology, 2016

The Wisconsin Card Sorting Test (WCST) is often regarded as a prototypical neuropsychological tes... more The Wisconsin Card Sorting Test (WCST) is often regarded as a prototypical neuropsychological test of set-shifting ability. However, it has been proposed that WCST performance involves cognitive processes other than set shifting, such as set maintenance and rule inference. Distinguishing between these processes is necessary for the meaningful interpretation of WCST performance deficits in neuropsychological populations. In the present studies, we aimed to concurrently measure processes of set shifting, set maintenance and rule inference in a computerized version of the WCST, and to dissociate these processes based on their dependence on working memory capacity. In Study 1, we manipulated the number of card-sorting rules to vary the demands placed on working memory-dependent processes of rule inference. As predicted, integration errors as a novel measure of rule-inference efficiency were selectively affected by increasing the number of rules from 3 to 4. In Study 2, we examined age-related changes in set shifting, set maintenance, and rule inference. We found a specific association between age and integration errors, indicating that rule inference, but not set shifting or set maintenance, is affected in older individuals. Rule inference on WCST-like card-sorting tasks appeared to be selectively impaired when the amount of information to be integrated in working memory increases or when working memory capacity is reduced (as in older individuals). Our findings indicate that measuring integration errors as an index of a distinct rule-inference process can improve the understanding and interpretability of WCST performance. (PsycINFO Database Record

Frontiers in Aging Neuroscience, 2015

A growing body of evidence implies psychological disturbances in amyotrophic lateral sclerosis (A... more A growing body of evidence implies psychological disturbances in amyotrophic lateral sclerosis (ALS). Specifically, executive dysfunctions occur in up to 50% of ALS patients. The recently shown presence of cytoplasmic aggregates (TDP-43) in ALS patients and in patients with behavioral variants of frontotemporal dementia suggests that these two disease entities form the extremes of a spectrum. The present study aimed at investigating behavioral and electrophysiological indices of conflict processing in patients with ALS. A non-verbal variant of the flanker task demanded two-choice responses to target stimuli that were surrounded by flanker stimuli which either primed the correct response or the alternative response (the latter case representing the conflict situation). Behavioral performance, event-related potentials (ERP), and lateralized readiness potentials (LRP) were analyzed in 21 ALS patients and 20 controls. In addition, relations between these measures and executive dysfunctions were examined. ALS patients performed the flanker task normally, indicating preserved conflict processing. In similar vein, ERP and LRP indices of conflict processing did not differ between groups. However, ALS patients showed enhanced posterior negative ERP waveform deflections, possibly indicating increased modulation of visual processing by frontoparietal networks in ALS. We also found that the presence of executive dysfunctions was associated with more error-prone behavior and enhanced LRP amplitudes in ALS patients, pointing to a prefrontal pathogenesis of executive dysfunctions and to a potential link between prefrontal and motor cortical functional dysregulation in ALS, respectively.

Scientific Reports, 2015

Time-consuming processes of task-set reconfiguration have been shown to contribute to the costs o... more Time-consuming processes of task-set reconfiguration have been shown to contribute to the costs of switching between cognitive tasks. We describe and probe a novel mechanism serving to reduce the costs of task-set reconfiguration. We propose that when individuals are uncertain about the currently valid task, one task set is activated for execution while other task sets are maintained at a pre-active state in cognitive cache. We tested this idea by assessing an event-related potential (ERP) index of task-set reconfiguration in a three-rule task-switching paradigm involving varying degrees of task uncertainty. In high-uncertainty conditions, two viable tasks were equally likely to be correct whereas in low-uncertainty conditions, one task was more likely than the other. ERP and performance measures indicated substantial costs of task-set reconfiguration when participants were required to switch away from a task that had been likely to be correct. In contrast, task-set-reconfiguration costs were markedly reduced when the previous task set was chosen under high task uncertainty. These results suggest that cognitive caching of alternative task sets adds to human cognitive flexibility under high task uncertainty.

Neuropsychology, Jan 13, 2015

Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often d... more Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often described but poorly understood. Specifically, research on patients' ability to flexibly shift between cognitive sets is still scarce and unsystematic. The present study set out to compensate for this lack by providing an in-depth analysis of ALS-related set-shifting impairments. We first present a quantitative overview of the literature revealing that the Wisconsin Card Sorting Test (WCST) is sensitive to set-shifting impairments in ALS. Moreover, we evaluated patients' performance on a computerized task-switching paradigm modeled after the WCST to elucidate the neurocognitive processes underlying their set-shifting impairments. Twenty-one ALS patients and 21 age- and education-matched controls were required to respond to changing task demands while their EEG was being measured. Behavioral results revealed significant set-shifting deficits in patients suffering from ALS. Executiv...

Neuropsychology, 2015

Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often d... more Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often described but poorly understood. Specifically, research on patients' ability to flexibly shift between cognitive sets is still scarce and unsystematic. The present study set out to compensate for this lack by providing an in-depth analysis of ALS-related set-shifting impairments. We first present a quantitative overview of the literature revealing that the Wisconsin Card Sorting Test (WCST) is sensitive to set-shifting impairments in ALS. Moreover, we evaluated patients' performance on a computerized task-switching paradigm modeled after the WCST to elucidate the neurocognitive processes underlying their set-shifting impairments. Twenty-one ALS patients and 21 age- and education-matched controls were required to respond to changing task demands while their EEG was being measured. Behavioral results revealed significant set-shifting deficits in patients suffering from ALS. Executive deficits were accompanied by substantial alterations of event-related brain activity. While switch cues elicited a more positive posterior event-related potential (ERP) waveform than repeat cues in healthy controls, ERP amplitudes did not vary as a function of switching demand in ALS patients. Individual differences in posterior switch positivity were reliably associated with patients' performance on neuropsychological tests of executive functioning. The absence of switch-related ERP modulations appears to be a sensitive indicator of executive deficits in ALS patients. Our results suggest that ALS compromises the frontoparietal brain networks involved in anticipatory set-shifting, rendering patients unable to flexibly adapt to changes in environmental contingencies. (PsycINFO Database Record

Journal of European Psychology Students, 2014

After having completed an initial self-control task, individuals typically show less self-control... more After having completed an initial self-control task, individuals typically show less self-controlled behavior on a consecutive task. In addition, this so-called ego-depletion effect is assumed to be alleviated by the consumption of sugar-containing drinks. However, a recent replication study indicates that this effect has been substantially overestimated. In contrast to mainstream ego-depletion research, initial and consecutive self-control tasks were identical in that study. Here we evaluate the generalizability of these results by testing 70 participants on a dual-task paradigm involving dissimilar tasks. Between self-control tasks, participants consumed a drink containing either sugar or an artificial sweetener. Results suggest that sugar consumption does not counteract ego depletion even when dissimilar self-control tasks are used.

Clinical Neurophysiology

When task-irrelevant salient stimuli are added to perceptual discrimination tasks, these stimuli ... more When task-irrelevant salient stimuli are added to perceptual discrimination tasks, these stimuli are typically found to elicit a prominent frontal P3a component in the event-related potential (ERP) of healthy participants. Recently, comparable P3a-like waveforms have been detected in tasks tapping more sophisticated cognitive functions including mental set shifting and probabilistic decision making. By analyzing the common and divergent features of P3a-like activity across these paradigms, the present study aimed at elucidating its functional role in executive processing. Sixteen young and healthy participants completed both auditory and visual variants of the three-stimulus oddball paradigm, a task-switching paradigm closely modeled to the Wisconsin Card Sorting Test and a decision-making task requiring the integration of probabilistic information. We found frontal P3a-like amplitudes to be enhanced by novel stimuli, feedback stimuli informing about changes in task contingencies an...

Resources, Conservation and Recycling, 2014

ABSTRACT The present study aims at providing an improved understanding of the environmental facto... more ABSTRACT The present study aims at providing an improved understanding of the environmental factors affecting pro-environmental behavior. To this end, we introduce the economic concept of bounded rationality to the domain of recycling behavior, hypothesizing that the subjective costs of recycling are a better predictor of an individual's tendency to recycle than the objective costs. At the chosen study site, recyclables needed to be disposed of at collection centers distributed throughout the city, allowing for the analysis of recycling-related costs by assessing the distance between participants’ residence and the nearest collection center. Results from an online questionnaire completed by N = 306 citizens indicate that the perceived distance to the recycling facilities is more closely related to recycling behavior than the actual distance. By means of hierarchical regression analyses, we demonstrate that the perceived distance explains unique variance in recycling behavior while the actual distance conveys only redundant information. Surprisingly, the predictive potential of participants’ distance estimates appeared to be significantly larger for recycling behavior than for recycling intention. The implications of our results are discussed with regard to potential opportunities to promote recycling behavior by targeting individuals’ biased perception of recycling-related costs.

Human Nature, 2015

Numerous laboratory experiments suggest that mechanisms of indirect reciprocity might account for... more Numerous laboratory experiments suggest that mechanisms of indirect reciprocity might account for human cooperation. However, conclusive field data supporting the predictions of indirect reciprocity in everyday life situations is still scarce. Here, we attempt to compensate for this lack by examining the determinants of cooperative behavior in a German supermarket. Our methods were as follows: Confederates of the experimenter lined up at the checkout, apparently to buy a single item. As an act of cooperation, the waiting person in front (the potential helper) could allow the confederate to go ahead. By this means, the potential helper could take a cost (additional waiting time) by providing the confederate with a benefit (saved waiting time). We recorded the potential helpers' behavior and the number of items they purchased as a quantitative measure proportional to the confederate's benefit. Moreover, in a field experimental design, we varied the confederates' image by manipulating the item they purchased (beer vs. water). As predicted, the more waiting time they could save, the more likely the confederates were to receive cooperation. This relationship was moderated by the confederates' image. Cost-to-benefit ratios were required to be more favorable for beer-purchasing individuals to receive cooperation. Our results demonstrate that everyday human cooperation can be studied unobtrusively in the field and that cooperation among strangers is selective in a way that is consistent with current models of indirect reciprocity.

Neuroscience & Biobehavioral Reviews, 2016

Cognitive impairment is a common non-motor symptom of Parkinson's... more Cognitive impairment is a common non-motor symptom of Parkinson's disease (PD), but the nature of cognitive changes varies considerably between individuals. According to the dual-syndrome hypothesis, one cluster of patients is characterized by deficits in executive function that may be related to fronto-striatal dysfunction. Other patients primarily show non-frontal cognitive impairments that progress rapidly to PD dementia (PDD). We provide a comprehensive review of event-related potential (ERP) studies to identify ERP measures substantiating the heterogeneity of cognitive impairment in PD. Our review revealed evidence for P3b and mismatch-negativity alterations in PDD, but not in non-demented PD, indicating that alterations of these ERPs constitute electrophysiological markers for PDD. In contrast, ERP correlates of executive functions, such as NoGo-P3, N2 and error(-related) negativity (Ne/ERN), appear to be attenuated in non-demented PD patients in a dopamine-dependent manner. Hence, ERP measures confirm and yield distinct electrophysiological markers for the heterogeneity of cognitive impairment in PD. We discuss limitations and open questions of the ERP approach and provide directions and predictions for future ERP research.

Brain, 1995

Activity of the supplementary motor area may be inferred from movement-related potentials (MRPs) ... more Activity of the supplementary motor area may be inferred from movement-related potentials (MRPs) which are associated with the preparation and execution of voluntary, or internally determined movements. Supplementary motor area activity may be abnormal in Parkinson's disease since its major input from the basal ganglia is disrupted. Investigation of the abnormalities in supplementary motor area activity associated with movement deficits in Parkinson's disease may therefore reveal functions of the basal ganglia and the supplementary motor area. Movement-related potentials associated with sequential movements were investigated under various cueing conditions in Parkinson's disease subjects and age-matched controls. In controls, MRPs revealed involvement of the supplementary motor area in movements which can be internally determined (non-cued and externally cued, predictable movements, but not unpredictable movements). In Parkinson's disease, however, the supplementary motor area was only involved in movements which must be internally determined (non-cued movements, but not externally cued movements); therefore impaired internal control mechanisms, operating via the supplementary motor area, are bypassed when external cues are given. As a result, Parkinson's disease patients are more reliant on external cues and are unable to use predictive models to internally guide movement. Supplementary motor area involvement also relied on the predictability (in controls) or presence (in Parkinson's disease) of timing cues and not spatial cues, indicating a role of the supplementary motor area and basal ganglia in the temporal organizations of sequential movement rather than the programming of specific movements. For non-cued movements, abnormalities in MRPs for Parkinson's disease subjects consisted of delayed MRP onset and peak times, and prolonged cortical activity following movement. These observations led to a proposed model of the interaction between the basal ganglia and the supplementary motor area, involving the temporal organization of voluntary and internally determined sequential movements.

Clinical Neurophysiology, 2016

Amyotrophic lateral sclerosis (ALS) has been associated with executive dysfunction, particularly ... more Amyotrophic lateral sclerosis (ALS) has been associated with executive dysfunction, particularly in the domain of cognitive set shifting. In a recent event-related potential (ERP) study, shifting-related cortical activity on a complex set-shifting paradigm was found to be attenuated in patients with ALS. Here, we investigated whether this ERP change could also be observed in a simplified set-shifting task adapted for potential clinical use, and in ALS patients without overt cognitive impairment. Twenty-six patients and 28 matched healthy controls (HC) completed a set-shifting paradigm involving two task rules and explicit task cues. Cue-locked ERPs were analyzed. ALS patients and HC did not differ in response latency or accuracy. In HC, cues that required shifting task rules elicited more positive parietal ERP waveforms than cues that signaled a rule repetition. This shifting-related amplitude modulation was absent in patients with ALS. The attenuation of ERP activity in ALS patients remained significant when participants with possible cognitive impairment were excluded. Electrophysiological measures can detect ALS-related changes in the neural substrates of set shifting even when these changes do not become apparent in neuropsychological assessment. These findings illustrate the potential utility of ERPs as indicators of cognitive change in ALS.

Accident; analysis and prevention, 2016

A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road ... more A large number of pedestrians and cyclists regularly ignore the traffic lights to cross the road illegally. In a recent analysis, illegal road crossing behavior has been shown to be enhanced in the presence of incongruent stimulus configurations. Pedestrians and cyclists are more likely to cross against a red light when exposed to an irrelevant conflicting green light. Here, we present experimental and observational data on the factors moderating the risk associated with incongruent traffic lights. In an observational study, we demonstrated that the conflict-related increase in illegal crossing rates is reduced when pedestrian and cyclist green light periods are long. In a laboratory experiment, we manipulated the color of the irrelevant signals to expose participants to different degrees of incongruency. Results revealed that individuals' performance gradually varied as a function of incongruency, suggesting that the negative impact of a conflicting green light can be reduced b...

Cognitive, Affective, & Behavioral Neuroscience, 2016

The capability of the human brain for Bayesian inference was assessed by manipulating probabilist... more The capability of the human brain for Bayesian inference was assessed by manipulating probabilistic contingencies in an urn-ball task. Event-related potentials (ERPs) were recorded in response to stimuli that differed in their relative frequency of occurrence (.18 to .82). A veraged ERPs with sufficient signal-to-noise ratio (relative frequency of occurrence > .5) were used for further analysis. Research hypotheses about relationships between probabilistic contingencies and ERP amplitude variations were formalized as (in-)equality constrained hypotheses. Conducting Bayesian model comparisons, we found that manipulations of prior probabilities and likelihoods were associated with separately modifiable and distinct ERP responses. P3a amplitudes were sensitive to the degree of prior certainty such that higher prior probabilities were related to larger frontally distributed P3a waves. P3b amplitudes were sensitive to the degree of likelihood certainty such that lower likelihoods were associated with larger parietally distributed P3b waves. These ERP data suggest that these antecedents of Bayesian inference (prior probabilities and likelihoods) are coded by the human brain.

Journal of the International Neuropsychological Society : JINS, 2016

Objectives Although primary dystonia is typically characterized as a movement disorder, it is als... more Objectives Although primary dystonia is typically characterized as a movement disorder, it is also associated with cognitive alterations in the domain of executive functioning which may arise from changes in cortico-basal ganglia circuits. Specifically, in comparison to healthy controls, patients with dystonia show deficits in neuropsychological tests of cognitive flexibility. However, it is unclear whether cognitive inflexibility is caused by the pathomechanisms underlying primary dystonia or by confounding factors such as depression or symptom-related distraction.Methods The present study aimed to eliminate these confounds by examining cognitive flexibility in dystonia patients and in patients with similar motor symptoms but without a comparable central pathophysiology. Eighteen patients with primary blepharospasm, a common form of dystonia affecting the muscles around the eyes, and 19 patients with hemifacial spasm, a facial nerve disorder causing similar eyelid spasms, completed...

Cortex; a journal devoted to the study of the nervous system and behavior, Jan 8, 2016

Impaired motor control in primary dystonia has been linked to cortico-basal ganglia alterations t... more Impaired motor control in primary dystonia has been linked to cortico-basal ganglia alterations that may also give rise to changes in executive functioning. However, no conclusive evidence for executive dysfunction in patients with primary dystonia has been reported yet. We conducted a meta-analysis of the relationship between primary dystonia and performance on the Wisconsin Card Sorting Test (WCST), an established test of executive functioning. Its results revealed a significant effect of medium size, indicating that primary dystonia is associated with moderate performance deficits on the WCST. Building on this finding, we conducted an event-related potential (ERP) study to elucidate the cognitive and neural mechanisms underlying executive dysfunction in primary dystonia. Eighteen patients with blepharospasm, a common form of primary focal dystonia, and 34 healthy matched controls completed a computerized version of the WCST. We specifically compared indicators of two distinct com...

Brain and Cognition, 2016

The human brain predicts events in its environment based on expectations, and unexpected events a... more The human brain predicts events in its environment based on expectations, and unexpected events are surprising. When probabilistic contingencies in the environment are precisely instructed, the individual can form expectations based on quantitative probabilistic information ('inference-based learning'). In contrast, when probabilistic contingencies are imprecisely instructed, expectations are formed based on the individual's cumulative experience ('experience-based learning'). Here, we used the urn-ball paradigm to investigate how variations in prior probabilities and in the precision of information about these priors modulate choice behavior and event-related potential (ERP) correlates of surprise. In the urn-ball paradigm, participants are repeatedly forced to infer hidden states responsible for generating observable events, given small samples of factual observations. We manipulated prior probabilities of the states, and we rendered the priors calculable or incalculable, respectively. The analysis of choice behavior revealed that the tendency to consider prior probabilities when making decisions about hidden states was stronger when prior probabilities were calculable, at least in some of our participants. Surprise-related P3b amplitudes were observed in both the calculable and the incalculable prior probability condition. In contrast, calculability of prior probabilities modulated anteriorly distributed ERP amplitudes: when prior probabilities were calculable, surprising events elicited enhanced P3a amplitudes. However, when prior probabilities were incalculable, surprise was associated with enhanced N2 amplitudes. Furthermore, interindividual variability in reliance on prior probabilities was associated with attenuated P3b surprise responses under calculable in comparison to incalculable prior probabilities. Our results suggest two distinct neural systems for probabilistic learning that are recruited depending on contextual cues such as the precision of probabilistic information. Individuals with stronger tendencies to rely on calculable prior probabilities seem to have better adapted expectations at their disposal, as indicated by an attenuation of their P3b surprise responses when prior probabilities are calculable.

Frontiers in Psychology, 2016

Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian model... more Cognitive determinants of probabilistic inference were examined using hierarchical Bayesian modeling techniques. A classic urn-ball paradigm served as experimental strategy, involving a factorial two (prior probabilities) by two (likelihoods) design. Five computational models of cognitive processes were compared with the observed behavior. Parameter-free Bayesian posterior probabilities and parameter-free base rate neglect provided inadequate models of probabilistic inference. The introduction of distorted subjective probabilities yielded more robust and generalizable results. A general class of (inverted) S-shaped probability weighting functions had been proposed; however, the possibility of large differences in probability distortions not only across experimental conditions, but also across individuals, seems critical for the model's success. It also seems advantageous to consider individual differences in parameters of probability weighting as being sampled from weakly informative prior distributions of individual parameter values. Thus, the results from hierarchical Bayesian modeling converge with previous results in revealing that probability weighting parameters show considerable task dependency and individual differences. Methodologically, this work exemplifies the usefulness of hierarchical Bayesian modeling techniques for cognitive psychology. Theoretically, human probabilistic inference might be best described as the application of individualized strategic policies for Bayesian belief revision.

Neuropsychology, 2016

The Wisconsin Card Sorting Test (WCST) is often regarded as a prototypical neuropsychological tes... more The Wisconsin Card Sorting Test (WCST) is often regarded as a prototypical neuropsychological test of set-shifting ability. However, it has been proposed that WCST performance involves cognitive processes other than set shifting, such as set maintenance and rule inference. Distinguishing between these processes is necessary for the meaningful interpretation of WCST performance deficits in neuropsychological populations. In the present studies, we aimed to concurrently measure processes of set shifting, set maintenance and rule inference in a computerized version of the WCST, and to dissociate these processes based on their dependence on working memory capacity. In Study 1, we manipulated the number of card-sorting rules to vary the demands placed on working memory-dependent processes of rule inference. As predicted, integration errors as a novel measure of rule-inference efficiency were selectively affected by increasing the number of rules from 3 to 4. In Study 2, we examined age-related changes in set shifting, set maintenance, and rule inference. We found a specific association between age and integration errors, indicating that rule inference, but not set shifting or set maintenance, is affected in older individuals. Rule inference on WCST-like card-sorting tasks appeared to be selectively impaired when the amount of information to be integrated in working memory increases or when working memory capacity is reduced (as in older individuals). Our findings indicate that measuring integration errors as an index of a distinct rule-inference process can improve the understanding and interpretability of WCST performance. (PsycINFO Database Record

Frontiers in Aging Neuroscience, 2015

A growing body of evidence implies psychological disturbances in amyotrophic lateral sclerosis (A... more A growing body of evidence implies psychological disturbances in amyotrophic lateral sclerosis (ALS). Specifically, executive dysfunctions occur in up to 50% of ALS patients. The recently shown presence of cytoplasmic aggregates (TDP-43) in ALS patients and in patients with behavioral variants of frontotemporal dementia suggests that these two disease entities form the extremes of a spectrum. The present study aimed at investigating behavioral and electrophysiological indices of conflict processing in patients with ALS. A non-verbal variant of the flanker task demanded two-choice responses to target stimuli that were surrounded by flanker stimuli which either primed the correct response or the alternative response (the latter case representing the conflict situation). Behavioral performance, event-related potentials (ERP), and lateralized readiness potentials (LRP) were analyzed in 21 ALS patients and 20 controls. In addition, relations between these measures and executive dysfunctions were examined. ALS patients performed the flanker task normally, indicating preserved conflict processing. In similar vein, ERP and LRP indices of conflict processing did not differ between groups. However, ALS patients showed enhanced posterior negative ERP waveform deflections, possibly indicating increased modulation of visual processing by frontoparietal networks in ALS. We also found that the presence of executive dysfunctions was associated with more error-prone behavior and enhanced LRP amplitudes in ALS patients, pointing to a prefrontal pathogenesis of executive dysfunctions and to a potential link between prefrontal and motor cortical functional dysregulation in ALS, respectively.

Scientific Reports, 2015

Time-consuming processes of task-set reconfiguration have been shown to contribute to the costs o... more Time-consuming processes of task-set reconfiguration have been shown to contribute to the costs of switching between cognitive tasks. We describe and probe a novel mechanism serving to reduce the costs of task-set reconfiguration. We propose that when individuals are uncertain about the currently valid task, one task set is activated for execution while other task sets are maintained at a pre-active state in cognitive cache. We tested this idea by assessing an event-related potential (ERP) index of task-set reconfiguration in a three-rule task-switching paradigm involving varying degrees of task uncertainty. In high-uncertainty conditions, two viable tasks were equally likely to be correct whereas in low-uncertainty conditions, one task was more likely than the other. ERP and performance measures indicated substantial costs of task-set reconfiguration when participants were required to switch away from a task that had been likely to be correct. In contrast, task-set-reconfiguration costs were markedly reduced when the previous task set was chosen under high task uncertainty. These results suggest that cognitive caching of alternative task sets adds to human cognitive flexibility under high task uncertainty.

Neuropsychology, Jan 13, 2015

Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often d... more Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often described but poorly understood. Specifically, research on patients' ability to flexibly shift between cognitive sets is still scarce and unsystematic. The present study set out to compensate for this lack by providing an in-depth analysis of ALS-related set-shifting impairments. We first present a quantitative overview of the literature revealing that the Wisconsin Card Sorting Test (WCST) is sensitive to set-shifting impairments in ALS. Moreover, we evaluated patients' performance on a computerized task-switching paradigm modeled after the WCST to elucidate the neurocognitive processes underlying their set-shifting impairments. Twenty-one ALS patients and 21 age- and education-matched controls were required to respond to changing task demands while their EEG was being measured. Behavioral results revealed significant set-shifting deficits in patients suffering from ALS. Executiv...

Neuropsychology, 2015

Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often d... more Executive dysfunctions in patients suffering from amyotrophic lateral sclerosis (ALS) are often described but poorly understood. Specifically, research on patients' ability to flexibly shift between cognitive sets is still scarce and unsystematic. The present study set out to compensate for this lack by providing an in-depth analysis of ALS-related set-shifting impairments. We first present a quantitative overview of the literature revealing that the Wisconsin Card Sorting Test (WCST) is sensitive to set-shifting impairments in ALS. Moreover, we evaluated patients' performance on a computerized task-switching paradigm modeled after the WCST to elucidate the neurocognitive processes underlying their set-shifting impairments. Twenty-one ALS patients and 21 age- and education-matched controls were required to respond to changing task demands while their EEG was being measured. Behavioral results revealed significant set-shifting deficits in patients suffering from ALS. Executive deficits were accompanied by substantial alterations of event-related brain activity. While switch cues elicited a more positive posterior event-related potential (ERP) waveform than repeat cues in healthy controls, ERP amplitudes did not vary as a function of switching demand in ALS patients. Individual differences in posterior switch positivity were reliably associated with patients' performance on neuropsychological tests of executive functioning. The absence of switch-related ERP modulations appears to be a sensitive indicator of executive deficits in ALS patients. Our results suggest that ALS compromises the frontoparietal brain networks involved in anticipatory set-shifting, rendering patients unable to flexibly adapt to changes in environmental contingencies. (PsycINFO Database Record

Journal of European Psychology Students, 2014

After having completed an initial self-control task, individuals typically show less self-control... more After having completed an initial self-control task, individuals typically show less self-controlled behavior on a consecutive task. In addition, this so-called ego-depletion effect is assumed to be alleviated by the consumption of sugar-containing drinks. However, a recent replication study indicates that this effect has been substantially overestimated. In contrast to mainstream ego-depletion research, initial and consecutive self-control tasks were identical in that study. Here we evaluate the generalizability of these results by testing 70 participants on a dual-task paradigm involving dissimilar tasks. Between self-control tasks, participants consumed a drink containing either sugar or an artificial sweetener. Results suggest that sugar consumption does not counteract ego depletion even when dissimilar self-control tasks are used.

Clinical Neurophysiology

When task-irrelevant salient stimuli are added to perceptual discrimination tasks, these stimuli ... more When task-irrelevant salient stimuli are added to perceptual discrimination tasks, these stimuli are typically found to elicit a prominent frontal P3a component in the event-related potential (ERP) of healthy participants. Recently, comparable P3a-like waveforms have been detected in tasks tapping more sophisticated cognitive functions including mental set shifting and probabilistic decision making. By analyzing the common and divergent features of P3a-like activity across these paradigms, the present study aimed at elucidating its functional role in executive processing. Sixteen young and healthy participants completed both auditory and visual variants of the three-stimulus oddball paradigm, a task-switching paradigm closely modeled to the Wisconsin Card Sorting Test and a decision-making task requiring the integration of probabilistic information. We found frontal P3a-like amplitudes to be enhanced by novel stimuli, feedback stimuli informing about changes in task contingencies an...

Resources, Conservation and Recycling, 2014

ABSTRACT The present study aims at providing an improved understanding of the environmental facto... more ABSTRACT The present study aims at providing an improved understanding of the environmental factors affecting pro-environmental behavior. To this end, we introduce the economic concept of bounded rationality to the domain of recycling behavior, hypothesizing that the subjective costs of recycling are a better predictor of an individual's tendency to recycle than the objective costs. At the chosen study site, recyclables needed to be disposed of at collection centers distributed throughout the city, allowing for the analysis of recycling-related costs by assessing the distance between participants’ residence and the nearest collection center. Results from an online questionnaire completed by N = 306 citizens indicate that the perceived distance to the recycling facilities is more closely related to recycling behavior than the actual distance. By means of hierarchical regression analyses, we demonstrate that the perceived distance explains unique variance in recycling behavior while the actual distance conveys only redundant information. Surprisingly, the predictive potential of participants’ distance estimates appeared to be significantly larger for recycling behavior than for recycling intention. The implications of our results are discussed with regard to potential opportunities to promote recycling behavior by targeting individuals’ biased perception of recycling-related costs.