The violation of expectation (VOE) paradigm and related habituation methods are the primary tools used to study higher-level cognition in preverbal infants. A common assumption of the paradigm is that longer looking to impossible events than possible events is indicative of infants' surprise at witnessing the impossible. Experiments can thus be designed to reveal infants' prior expectations for the behaviour of objects in the environment and so forth. This thesis explored the nature of infants' expectations in VOE-type events, and introduces pupil dilation as a novel dependent measure in tests of infant cognition. Chapter 1 reviews the history of, and rationale for, the use of habituation testing in infants, and presents the case for pupil dilation's potential as a viable and useful measure for tests in infancy. Chapters 2, 3 and 4 present four experiments in which infants are habituated to either possible or impossible events, before being tested on all event types, in order to explore the role of online learning in the formation of infants' expectations in VOE tasks. Both looking times and pupil dilation data were used as dependent measures in each of these tasks. In Chapter 5 Baillargeon's (1987; Baillargeon, Spelke, & Wasserman, 1985) influential 'drawbridge' experiments and the many subsequent replications of them are reviewed before a further replication is introduced in which the novel contribution of pupil dilation data is assessed. The discussion focuses on the findings of the empirical work of this thesis, and concludes that it is crucial to incorporate efforts to refute hypotheses into the designs of tests for infant cognition, and also that pupil data is a valuable complementary measure to, and potentially even superior than, looking times.

No description available.

Novel sounds in the auditory oddball paradigm elicit a biphasic dilation of the pupil (PDR) and P3a as well as novelty P3 event-related potentials (ERPs). The biphasic PDR has been hypothesized to reflect the relaxation of the iris sphincter muscle due to parasympathetic inhibition and the constriction of the iris dilator muscle due to sympathetic activation. We measured the PDR and the P3 to neutral and to emotionally arousing negative novels in dark and moderate lighting conditions. By means of principal component analysis (PCA) of the PDR data we extracted two components: the early one was absent in darkness and, thus, presumably reflects parasympathetic inhibition, whereas the late component occurred in darkness and light and presumably reflects sympathetic activation. Importantly, only this sympathetic late component was enhanced for emotionally arousing (as compared to neutral) sounds supporting the hypothesis that emotional arousal specifically activates the sympathetic nervous system. In the ERPs we observed P3a and novelty P3 in response to novel sounds. Both components were enhanced for emotionally arousing (as compared to neutral) novels. Our results demonstrate that sympathetic and parasympathetic contributions to the PDR can be separated and link emotional arousal to sympathetic nervous system activation.

No description available.

Emotion is thought to modulate the long-term fate of memories. Experiences that elicit an emotional response tend to be better remembered than comparatively unemotional events, while the emotional charge associated with these memories diminishes over time. Sleep – in particular rapid-eye movement (REM) and slow-wave sleep (SWS) - has been implicated in both the selective strengthening and affective uncharging of emotional memories. According to the sleep to forget, sleep to remember (SFSR) hypothesis, both processes occur in parallel during REM sleep. Although evidence strongly supports a role of REM sleep in the selective consolidation of emotional memories, it is far less clear to what extent sleep is involved in the development of emotional charge. While some studies support a primary role of REM in habituation (i.e. the decrease of emotional charge), others suggest a more central role of SWS. Further, existing literature indicates that the physiological (bottom-up) and cognitive (top-down) components of emotional responses may be differentially processed across sleep. Chapter 2 proposes complementary functions of REM and SWS in emotional memory processes based on a combination of evidence from rodent and human research. The experiments presented in this thesis employed polysomnography (PSG), subjective arousal testing, pupillometry, targeted memory reactivation (TMR), and transcranial alternating current stimulation (tACs) to investigate the respective roles of REM and SWS in the overnight development of subjective and autonomic arousal in response to negative emotional and neutral stimuli. In Chapter 3 I assessed how subjective and autonomic responses to neutral and negative stimuli develop across 12 hours containing either nocturnal sleep or daytime wakefulness. I found that autonomic reactivity – indexed by pupil dilation – decreased across sleep but not wake, while subjective arousal did not change across either interval. In a further experiment, I investigated whether the placement of sleep within a 24 hour interval would affect habituation. Once again, autonomic arousal decreased significantly. Subjective arousal towards negative stimuli was found to decrease more if sleep followed rather than preceded daytime wakefulness within the 24 hour interval. In Chapter 4 I explored the role of REM sleep in emotional habituation by applying 5 Hz tACs in an attempt to entrain endogenous cortical theta (4-7 Hz) activity, which has previously been associated with emotional memory consolidation in humans. Surprisingly, I found that stimulation was associated with a reduction in theta power and no change in subjective or autonomic habituation compared to the sham control night. In Chapters 5 and 6, I addressed the contribution of memory reactivations during SWS and REM sleep, respectively, in emotional habituation using TMR. In Chapter 5, I found that TMR was associated with a decrease and simultaneous increase in autonomic habituation towards negative and neutral stimuli, respectively, without affecting overnight changes in subjective arousal. In contrast, in Chapter 6, TMR during REM sleep was associated with an increase in subjective habituation towards both neutral and negative stimuli without affecting autonomic responses. In conclusion, my results provide new insights to the role of sleep in emotional habituation. I have provided evidence that targeted memory reactivation during REM sleep can modulate the development of cognitive evaluations of emotion, while TMR during SWS may interfere with autonomic habituation. This suggests distinct emotional processing during REM and SWS, as well as a dissociation between subjective and autonomic habituation across sleep. These results are discussed in the light of previous research and the model of sleep-dependent emotional memory processing proposed in Chapter 2.

The concept of attention is complex and multifaceted and can be approached from many perspectives. One such perspective is of attention as a limited pool of resources. Kahneman’s (1973) model of limited capacity provides a basis for understanding constraints on attention, including the costs of divided attention. In the same vein as Kahneman’s model, the Framework for Understanding Effortful Listening (FUEL; Pichora-Fuller et al., 2016) applies the concept of limited attentional capacity to the demands of listening in a variety of contexts. The current work examines novel combinations of the methods commonly used in the field of Cognitive Hearing Science to address questions about the nature of attention allocation when listening in noise and under the constraints of divided attention. I first combined listening in noise with a secondary continuous working memory task and measured pupillary response as an index of cognitive work and listening effort. Here, I found that listening task demands affect performance on the working memory task. The shared demands of listening and working memory were not, however, evident in the pupil dilation patterns. As a result, I followed these findings by employing a different divided attention method. With the use of a temporally discrete secondary task that either closely overlapped with the listening task or did not closely overlap, I found the same carryover effects of listening demands on secondary task. Most importantly, I found that these demands interacted and were clearly present in the pupil dilation patterns, demonstrating the importance of the timing of the task demands. Together, the studies in this thesis provide evidence that these two secondary tasks access the same attentional resources as those accessed in the primary listening task and that this overlapping demand for resources can be seen in the pupillary response. / Thesis / Doctor of Philosophy (PhD) / Listening to speech in a noisy environment is a cognitively difficult and effortful task. Attending to more than one task at a time is similarly demanding and effortful. These two kinds of tasks are assumed to use the same limited pool of cognitive resources that we have available to us. This thesis combines listening in noise with divided attention tasks to demonstrate this overlap in demands for cognitive resources using novel combinations of these kinds of tasks. Additionally, this thesis uses the pupillary response—a well-studied index of cognitive effort—to further examine the nature of these overlapping task demands. These studies found that the demands of these tasks do, in fact, overlap, and contribute evidence to the current literature supporting the underlying assumption that these two tasks, and the pupillary response as a measure of effort, are accessing the same pool of limited resources.

No description available.

As humans age, the attenuation of dopamine and norepinephrine neuromodulation in the fronto-striatal network could lead to deficits in decision-making and reward learning. However, the questions about the nature of how age-related decline in the dopamine and norepinephrine systems may alter decision-making and reward learning are not well understood. This doctoral dissertation used a multimodal approach to investigate the contributions of dopamine and norepinephrine in decision-making and reward learning in old age. The first study of this dissertation focused on how age-related decline in the norepinephrine system may affect anticipatory values and reward prediction errors during reward learning. Specifically, a probabilistic decision-making task was conducted, and a reinforcement Q-learning model was applied to investigate anticipatory values of choice options for each trial and individual’s value sensitivity. Potential psychophysiological proxies of norepinephrine functioning, such as task-related pupillary responses and locus coeruleus structural integrity, were assessed in younger and older adults. Results showed that after the choice options and feedback were shown, younger adults’ pupil dilations negatively correlated with anticipatory values, suggesting uncertainty about outcome probabilities. However, this effect was smaller in the choice phase and absent in the feedback phase in older adults, indicating impairments in value estimation and updating in old age. Although older adults showed a lower locus coeruleus integrity than younger adults, which might indicate reduced norepinephrine functioning, individual’s value sensitivity was only associated with task-related pupil dilations but not with locus coeruleus integrity. The second study investigated whether increasing the saliency of specific information of choice options may improve older adults’ decision performance during value-based decision-making and what the mechanisms of increasing information saliency could be. In particular, the saliency of outcome probabilities was highlighted using a color-coding scheme as a decision-aid in a mixed lottery choice task. Spontaneous eye-blink rate and pupillary responses were measured in younger and older adults as potential proxies of dopamine and norepinephrine functioning, respectively. In addition, the task-related pupil dilations also served as the function of cognitive demands during value computation. Results showed that older adults exhibited lower value sensitivity than younger adults; however, increasing information saliency benefitted choice behaviors in both age groups. Furthermore, the decision-aid reduced pupil size during decision-making in both age groups, suggesting decreased cognitive demands of value computation. The beneficial effects from the decision-aid were related to individual’s value sensitivity and the psychophysiological indicators of dopamine and norepinephrine functioning in old age. Lastly, in the third study, a time-vary drift diffusion model that includes starting time parameters was applied to fit the behavioral datasets acquired from the second study. It was aimed to better understand how increasing the saliency of outcome probabilities may affect the dynamics of value-based decision-making. Results showed that older adults started to consider probability, relative to magnitude information, sooner than younger adults, but that their evidence accumulation processes were less sensitive to reward probabilities than that of younger adults. These findings may indicate a noisier and more stochastic information accumulation process during value-based decisions in old age. The decision-aid increased the influence of probability information on the evidence accumulation rate in both age groups but did not alter the relative timing of accumulation for probability versus magnitude in either group. Taken together, the findings in this dissertation not only showed age-related deficits in decision-making and reward learning but also demonstrated that the psychophysiological measures such as spontaneous eye-blink rate, pupillary responses, and locus coeruleus structural integrity may serve as indicators of age and/or individual differences in dopamine and norepinephrine functioning during decision-making and reward-based learning. Moreover, the model-based approach further unraveled age-related alterations in the psychometrics and dynamics of the decision process. The present dissertation may help to identify mechanisms to promote successful aging and the discovery of understanding the role of dopamine and norepinephrine neuromodulation in many fundamental cognitive functions.

Den fysiska arbetsmiljön är viktig för hälsan. Den kontorstypen vi arbetar i har en betydande påverkan på individen. Vi vet idag att buller, speciellt över en längre tid bidrar till negativa hälsoeffekter. Trots det utformar vi kontor med öppnare landskap där arbetstagare inte kan kontrollera bakgrundsljudet. Den här studien genomförs i en kontrollerad miljö med syfte att synliggöra hur det kan vara att arbeta i ett öppet kontorslandskap och i ett vanligt kontor. Studien mäter både upplevd och observerad arbetsbelastning, samt hur dessa skiljer sig åt i en tyst miljö och en miljö med bakgrundsljud. I experimentet använde vi oss av eye-tracking utrustning för att mäta pupillutvidgning, vilket kan ha ett samband med ökad mental arbetsbelastning. GSR-utrustning användes för att mäta känslosvall och deltagarnas upplevda arbetsbelastning mättes med hjälp av en NASA-TLX enkät. Resultatet visar att miljön med bakgrundsljud upplevdes störande under hela testet. Skillnader i pupillstorleken visade på en ökad mental arbetsbelastning när det fanns ljud i bakgrunden, men bara på de tester som innehöll en läsuppgift. Om arbetsbelastningen blir för hög, kan det enligt tidigare forskning, leda till en negativ påverkan på en persons hälsa. / The physical work environment is important for your health. The type of office we work in have a significant impact on the individual. We know today that noise, especially over a longer period of time contribute to negative health effects. Despite this we continue designing offices with open landscape where workers cannot control the background noise. This study is conducted in a controlled environment with the intention to get a view how it might be to work in an open landscape office and in a regular office. The study measure both perceived and observed mental load, and how these differ in a quiet environment and an environment with background noise. In the experiment we used eye-tracking equipment to measure pupil dilation, which may be associated with increased mental load. GSR-equipment was used to measure emotional arousal and participants perceived workload was measured using a NASA-TLX questionnaire. The result shows that the environment with background noise was experienced as disturbing throughout the test. Differences in pupil dilation showed an increased mental workload when there was sound in the background, but only on the tests that contained a reading task. If the workload becomes too high, it can, according to previous research, lead to a negative impact on a person’s health.

La charge de travail cognitive d'un pilote d'aviation, qui englobe sa capacité mentale à effectuer les manœuvres d'un avion, varie selon l’étape de pilotage et le nombre de tâches convergeant simultanément sur le pilote. Cette charge de travail peut entraîner des erreurs de pilotage aux conséquences graves. La plupart des erreurs se produisent pendant la procédure de décollage ou d'atterrissage. Cette étude vise à mesurer et prédire la charge de travail cognitive d'un pilote lors d'une procédure de décollage afin de mieux comprendre et potentiellement prévenir ces erreurs humaines. Pour y parvenir, nous avons créé une solution logicielle pour mesurer et surveiller en temps réel la fréquence cardiaque, la dilatation pupillaire et la charge de travail cognitive d'un pilote. Le logiciel est également capable de déclencher des événements de défaillance pour déclencher une modification de la charge de travail cognitive à la demande. À l'aide d'un casque électroencéphalogramme (EEG) permettant de mesurer l’activité électrique du cerveau, d'un moniteur de fréquence cardiaque, d'un eye tracker et d'un simulateur, nous avons créé une configuration d'environnement où les pilotes devaient faire décoller un avion A320 avec et sans pannes sans le savoir au préalable. Cette étude a rassemblé 136 décollages sur 13 pilotes pour plus de 9 heures de données de séries chronologiques, soit 2 millions de lignes combinées. De plus, nous avons étudié la relation entre la fréquence cardiaque, la dilatation de la pupille et la charge de travail cognitive lors d'une tâche critique. Cette étude a révélé, à l'aide d'une analyse statistique, qu'un moment critique, comme une panne de moteur, augmente la fréquence cardiaque, la dilatation de la pupille et la charge de travail cognitive d'un pilote. Ensuite, cette recherche a utilisé différents modèles d'apprentissage automatique et d'apprentissage en profondeur pour prédire la charge de travail cognitive d'un pilote pendant le décollage. Nous avons constaté qu'en utilisant un modèle d'apprentissage en profondeur long short-term memory empilé, nous étions en mesure de prédire la charge de travail cognitive 5 secondes dans le futur. Le modèle long short-term memory empilé a donné une erreur quadratique moyenne (MSE) de 44,09, une erreur racine quadratique moyenne (RMSE) de 6,64 et une erreur absolue moyenne de 5,28, prouvant qu'il est possible de prédire la charge de travail cognitive. / The cognitive workload for an aviation pilot, which englobes a pilot's mental capacity to perform aircraft's maneuvers, varies according to the piloting stage and the number of tasks converging simultaneously on the pilot. This workload can lead to piloting errors with severe consequences, where most errors occur during the takeoff or landing procedure. This study aims to predict the cognitive workload of a pilot during a takeoff procedure in order to better understand and potentially prevent these human errors. To achieve this, we created a software solution to measure and monitor in real-time the heart rate, pupil dilation, and cognitive workload of a pilot. The software is also capable of triggering failure events to trigger a change in cognitive workload on demand. Using an electroencephalogram (EEG) headset which measures the electrical brain activity, a heart rate monitor, an eye tracker, and a simulator, we created an environment setup where pilots had to take off an A320 airplane with and without failures without priorly knowing it. This study gathered 136 takeoffs across 13 pilots for more than 9 hours of time-series data, or 2 million rows combined. Moreover, we investigated the relation between heart rate, pupil dilation, and cognitive workload during a critical task. This study found, using statistical F-test analysis, that a critical moment, such as an engine failure, augments the heart rate, pupil dilation, and cognitive workload of a pilot. Next, this research utilized different machine learning and deep learning models to predict the cognitive workload of a pilot during takeoff. We found that, when using a stacked long short-term memory deep learning model, we were able to predict future cognitive workload 5 seconds into the future. The stacked long short-term memory model resulted in a mean square error of 44.09, a root mean square error of 6.64, and an mean absolute error of 5.28, demonstrating that it is possible to predict future cognitive workload.