Papers by Anne-Marie Brouwer
We tested the hypothesis that, either through training or selection, military personnel is more r... more We tested the hypothesis that, either through training or selection, military personnel is more resilient to stress than civilians, as indicated by several subjective and physiological measures. In addition, we examined the effect of stress on the perceived trustworthiness of faces in these two groups. Stress was induced in 45 civilian participants and 45 army participants through the Sing-a-Song Stress Test (SSST). In this paradigm seven neutral sentences are presented, each followed by a 60-s interval. An eighth sentence asks participants to sing a song aloud after the next (eighth or stress) interval. Participants rated the trustworthiness of five neutral faces, both before and after the SSST. Pupil size, heart rate, and skin conductance were adopted as physiological stress correlates. Stress response was calculated as the difference between the mean values over the last neutral interval and the stress interval. Subjective stress ratings were obtained before and after the SSST. The baseline levels of all physiological and subjective measures were the same in the army and civilian groups, while all measures showed a significant increase following the stressor. However, compared with the civilian group, army participants reported significantly less stress and showed significantly attenuated heart rate and skin conductance responses to the SSST. These results indicate higher stress resilience in the army compared with the civilian group. In addition, we found that perceived facial trustworthiness decreased after presentation of the stressor, suggesting that the effect of a stressor can influence in principle unrelated social judgments based on facial information.
Cognitive biases and heuristics are pervasive simplifications and distortions in judgement and re... more Cognitive biases and heuristics are pervasive simplifications and distortions in judgement and reasoning that systematically affect human decision making. Knowledge in this area may enable us to foresee and reduce detrimental effects of biases or to influence others more effectively. We therefore performed a literature study to assess the influence of personal characteristics (cognitive abilities, expertise, personality, cultural background) on the occurrence of cognitive biases. We found that each of the aforementioned factors can affect cognitive biases, though not much is known about the effects of culture. Also, factors that appear to reduce a cognitive bias may in fact mitigate (suppress or override) its behavioral effect rather than preventing the bias from occurring at all. The general picture that arises is that bias susceptibility and the occurrence of biases depend on thinking style (heuristic versus deliberate), where thinking style is associated with an individual " s personal characteristics. In general, biases are reduced when a deliberate (analytical) thinking style is applied. However, whether a specific (heuristic or deliberate) thinking style actually reduces or enhances a given type of bias also depends on the context.
Experimental Brain Research, 1998
Previous studies on how we hit moving targets have revealed that the direction in which we move o... more Previous studies on how we hit moving targets have revealed that the direction in which we move our hand is continuously adjusted on the basis of the target’s perceived position, with a delay of about 110 ms. In the present study we show that the acceleration of the hand is also under such continuous control. Subjects were instructed to hit moving targets (running spiders) as quickly as possible with a rod. We found that changing the velocity of the target influenced the speed with which the rod was moved. The influence was noticeable about 200 ms after the target’s velocity changed. The extent of the influence was consistent with a direct dependence of the acceleration of the hand on the target’s velocity. We conclude that the acceleration of the hand is continuously adjusted on the basis of the speed of the target, with a delay of about 200 ms.
Experimental Brain Research, 2003
Human-Computer Interaction, 2009
Eye movement recordings do not tell us whether observers are ’really looking’ or whether they are... more Eye movement recordings do not tell us whether observers are ’really looking’ or whether they are paying attention to something else than the visual environment. We want to determine whether an observer’s main current occupation is visual or not by investigating fixation patterns and EEG. Subjects were presented with auditory and visual stimuli. In some conditions, they focused on the
Frontiers in neuroscience, 2015
Estimating cognitive or affective state from neurophysiological signals and designing application... more Estimating cognitive or affective state from neurophysiological signals and designing applications that make use of this information requires expertise in many disciplines such as neurophysiology, machine learning, experimental psychology, and human factors. This makes it difficult to perform research that is strong in all its aspects as well as to judge a study or application on its merits. On the occasion of the special topic "Using neurophysiological signals that reflect cognitive or affective state" we here summarize often occurring pitfalls and recommendations on how to avoid them, both for authors (researchers) and readers. They relate to defining the state of interest, the neurophysiological processes that are expected to be involved in the state of interest, confounding factors, inadvertently "cheating" with classification analyses, insight on what underlies successful state estimation, and finally, the added value of neurophysiological measures in the co...
Frontiers in neuroscience, 2015
Proceedings of the 28th Annual European Conference on Cognitive Ergonomics - ECCE '10, 2010
Recent research shows that Virtual Reality (VR) exposure or bio-neuro feedback can help professio... more Recent research shows that Virtual Reality (VR) exposure or bio-neuro feedback can help professionals to cope with possibly traumatic events. This paper presents a neuro-bio VR system that combines both methods in order to further improve the prevention and therapy of trauma-related disorders. This system can harmonize the VR exposure to user's personal experiences by systematically showing scenes and stressors,
Lecture Notes in Computer Science, 2009
IEEE Transactions on Affective Computing, 2014
ABSTRACT High extraversion and conscientiousness and low neuroticism predict successful performan... more ABSTRACT High extraversion and conscientiousness and low neuroticism predict successful performance during and after stressful conditions. We investigated whether these personality factors are linked to stress sensitivity and to baseline physiology. Stress was induced through negative feedback on gaming performance. Stress sensitivity was determined as the difference in baseline physiological variables (skin conductance, heart rate and heart rate variability) before and after performing the game, as well as the difference in subjectively reported stress. While physiological results suggest that the game indeed induced stress, subjective reports do not. Maybe due to a low level of experienced stress, stress sensitivity (as indicated by the difference in heart rate) only correlates with conscientiousness and not with extraversion or neuroticism. The baseline measurements show the expected correlations between extraversion and both heart rate and heart rate variability—negative and positive respectively. The negative correlation between neuroticism and skin conductance is opposite to what we expected. While the exact mechanisms are not clear yet, the present results indicate that for healthy individuals, there are indeed measurable and consistent relations between physiology and personality. Hence, physiological indicators of personality may ultimately be of value as predictors of stress resiliency.
2014 IEEE Haptics Symposium (HAPTICS), 2014
ABSTRACT Brain Computer Interfaces (BCIs) rely on the user's brain activity to control eq... more ABSTRACT Brain Computer Interfaces (BCIs) rely on the user's brain activity to control equipment or computer devices. Many BCIs are based on imagined movement (called active BCIs) or the fact that brain patterns differ in reaction to relevant or attended stimuli in comparison to irrelevant or unattended stimuli (called reactive BCIs). Traditionally BCIs employ visual stimuli for feedback in active BCIs or as cues in reactive BCIs. However these vision-based BCIs are not suited for people with an impaired visual system and in situations where there is a threat of visual overload. Touch-based BCIs may be a viable alternative but they have hardly been explored so far. This paper presents the state-of-the-art in touch-based BCIs. The feasibility of tactile BCIs based on event related brain potentials to localized vibrations has been shown and tactile BCIs based on steady state brain responses to different vibration frequencies can compete with their gaze-free visual counterparts. We recommend the development of specific hardware paradigms and classification algorithms to improve performance further.
Computers & Geosciences, 2015
Motor control, 2003
Before an aspect of a movement that is predicted by a control theory can be considered as evidenc... more Before an aspect of a movement that is predicted by a control theory can be considered as evidence for that theory, it should be clear that this aspect is not the result of some other property of the movement. We investigate whether this condition is met in studies that claim to provide evidence for the tau-coupling theory. This theory proposes that moving targets are intercepted at a specified goal zone by maintaining a constant ratio between the tau (time to closure) of the gap between the hand and the goal zone and the tau of the gap between the hand and the moving target. In line with the theory, previous research has found a linear relationship between these two decreasing taus during the last part of such a movement. To investigate whether this linear relationship was a side-effect of smooth successful movements, we modeled smooth ballistic hand movements that were independent of the target's movement but led to successful interception. We found that the resulting taus of ...
Frontiers in neuroscience, 2014
While studies exist that compare different physiological variables with respect to their associat... more While studies exist that compare different physiological variables with respect to their association with mental workload, it is still largely unclear which variables supply the best information about momentary workload of an individual and what is the benefit of combining them. We investigated workload using the n-back task, controlling for body movements and visual input. We recorded EEG, skin conductance, respiration, ECG, pupil size and eye blinks of 14 subjects. Various variables were extracted from these recordings and used as features in individually tuned classification models. Online classification was simulated by using the first part of the data as training set and the last part of the data for testing the models. The results indicate that EEG performs best, followed by eye related measures and peripheral physiology. Combining variables from different sensors did not significantly improve workload assessment over the best performing sensor alone. Best classification accur...
International journal of psychophysiology : official journal of the International Organization of Psychophysiology, 2014
Learning to master a task is expected to be accompanied by a decrease in effort during task execu... more Learning to master a task is expected to be accompanied by a decrease in effort during task execution. We examine the possibility to monitor learning using physiological measures that have been reported to reflect effort or workload. Thirty-five participants performed different difficulty levels of the n-back task while a range of physiological and performance measurements were recorded. In order to dissociate non-specific time-related effects from effects of learning, we used the easiest level as a baseline condition. This condition is expected to only reflect non-specific effects of time. Performance and subjective measures confirmed more learning for the difficult level than for the easy level. The difficulty levels affected physiological variables in the way as expected, therewith showing their sensitivity. However, while most of the physiological variables were also affected by time, time-related effects were generally the same for the easy and the difficult level. Thus, in a w...
International Conference on Multimodal Interaction, 2009
In this paper, we describe a Brain Computer Interface (BCI) for navigation. The system is based o... more In this paper, we describe a Brain Computer Interface (BCI) for navigation. The system is based on detecting brain signals that are elicited by tactile stimulation on the torso indicating the desired direction.
Acta Astronautica, 2010
Recent advances in non-invasive brain–machine or brain–computer interfaces (BMIs/BCIs) have demon... more Recent advances in non-invasive brain–machine or brain–computer interfaces (BMIs/BCIs) have demonstrated that humans can control computers or simple robotic devices using only brain signals. These successes have lead to the suggestion that BMIs could significantly improve the safety and efficiency of space operations. Electroencephalography (EEG) and near infrared spectroscopy (NIRS)-based BMIs are most relevant for potential space applications due to
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Papers by Anne-Marie Brouwer