@phdthesis{Schwetlick2023,
  author    = {Schwetlick, Lisa},
  title     = {Data assimilation for neurocognitive models of eye movement},
  doi       = {10.25932/publishup-59828},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-598280},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 209},
  year      = {2023},
  abstract  = {Visual perception is a complex and dynamic process that plays a crucial role in how we perceive and interact with the world. The eyes move in a sequence of saccades and fixations, actively modulating perception by moving different parts of the visual world into focus. Eye movement behavior can therefore offer rich insights into the underlying cognitive mechanisms and decision processes. Computational models in combination with a rigorous statistical framework are critical for advancing our understanding in this field, facilitating the testing of theory-driven predictions and accounting for observed data. In this thesis, I investigate eye movement behavior through the development of two mechanistic, generative, and theory-driven models. The first model is based on experimental research regarding the distribution of attention, particularly around the time of a saccade, and explains statistical characteristics of scan paths. The second model implements a self-avoiding random walk within a confining potential to represent the microscopic fixational drift, which is present even while the eye is at rest, and investigates the relationship to microsaccades. Both models are implemented in a likelihood-based framework, which supports the use of data assimilation methods to perform Bayesian parameter inference at the level of individual participants, analyses of the marginal posteriors of the interpretable parameters, model comparisons, and posterior predictive checks. The application of these methods enables a thorough investigation of individual variability in the space of parameters. Results show that dynamical modeling and the data assimilation framework are highly suitable for eye movement research and, more generally, for cognitive modeling.},
  language  = {en}
}
@phdthesis{Risse2011,
  author    = {Risse, Sarah},
  title     = {Processing in the perceptual span : investigations with the n+2-boundary paradigm},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-60414},
  school      = {Universit{\"a}t Potsdam},
  year      = {2011},
  abstract  = {Cognitive psychology is traditionally interested in the interaction of perception, cognition, and behavioral control. Investigating eye movements in reading constitutes a field of research in which the processes and interactions of these subsystems can be studied in a well-defined environment. Thereby, the following questions are pursued: How much information is visually perceived during a fixation, how is processing achieved and temporally coordinated from visual letter encoding to final sentence comprehension, and how do such processes reflect on behavior such as the control of the eyes' movements during reading. Various theoretical models have been proposed to account for the specific eye-movement behavior in reading (for a review see Reichle, Rayner, \& Pollatsek, 2003). Some models are based on the idea of shifting attention serially from one word to the next within the sentence whereas others propose distributed attention allocating processing resources to more than one word at a time. As attention is assumed to drive word recognition processes one major difference between these models is that word processing must either occur in strict serial order, or that word processing is achieved in parallel. In spite of this crucial difference in the time course of word processing, both model classes perform well on explaining many of the benchmark effects in reading. In fact, there seems to be not much empirical evidence that challenges the models to a point at which their basic assumptions could be falsified. One issue often perceived as being decisive in the debate on serial and parallel word processing is how not-yet-fixated words to the right of fixation affect eye movements. Specifically, evidence is discussed as to what spatial extent such parafoveal words are previewed and how this influences current and subsequent word processing. Four experiments investigated parafoveal processing close to the spatial limits of the perceptual span. The present work aims to go beyond mere existence proofs of previewing words at such spatial distances. Introducing a manipulation that dissociates the sources of long-range preview effects, benefits and costs of parafoveal processing can be investigated in a single analysis and the differing impact is tracked across a three-word target region. In addition, the same manipulation evaluates the role of oculomotor error as the cause of non-local distributed effects. In this respect, the results contribute to a better understanding of the time course of word processing inside the perceptual span and attention allocation during reading.},
  language  = {en}
}
@phdthesis{Meinke2006,
  author    = {Meinke, Anja},
  title     = {Nikotineffekte auf r{\"a}umliche Aufmerksamkeitsprozesse bei Nichtrauchern},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-7659},
  school      = {Universit{\"a}t Potsdam},
  year      = {2006},
  abstract  = {Nikotin in den unterschiedlichsten Darreichungsformen verringert bei verschiedenen Spezies im r{\"a}umlichen Hinweisreizparadigma die Kosten invalider Hinweisreize. Welcher Teilprozess genau durch Nikotin beeinflusst wird, ist bislang nicht untersucht worden. Die g{\"a}ngige Interpretation ist, daß Nikotin das Losl{\"o}sen von Aufmerksamkeit von einem bisher beachteten Ort erleichtert. In f{\"u}nf Studien, drei elektrophysiologischen und zwei behavioralen wurden drei m{\"o}gliche Mechanismen der Nikotinwirkung an Nichtrauchern untersucht. Experiment 1 und 2 gingen der Frage nach, ob Nikotin eine Modulation sensorischer gain Kontrolle bewirkt. Dazu wurden ereigniskorrelierte Potentiale (EKP) im Posner-Paradigma erhoben und die Wirkung von Nikotin auf die aufmerksamkeitsassoziierten Komponenten P1 und N1 betrachtet. Nikotin verringerte die Kosten invalider Hinweisreize bei Aufmerksamkeitslenkung durch endogene Hinweisreize, nicht aber bei exogenen Hinweisreizen. Die P1 und N1 Komponenten zeigten sich unbeeinflusst von Nikotin, damit findet also die Annahme einer Wirkung auf sensorische Suppression keine Unterst{\"u}tzung. In Experiment 3 und 4 wurde untersucht, ob Nikotin einen Effekt auf kostentr{\"a}chtige unwillk{\"u}rliche Aufmerksamkeitsverschiebungen, Distraktionen, hat. In Experiment 3 wurden in einem r{\"a}umlichen Daueraufmerksamkeitsparadigma Distraktionen durch deviante Stimulusmerkmale ausgel{\"o}st und die Wirkung von Nikotin auf eine distraktionsassoziierte Komponente des EKP, die P3a, betrachtet. In Experiment 4 wurde in einem Hinweisreizparadigma durch zus{\"a}tzliche Stimuli eine Distraktion ausgel{\"o}st und die Nikotinwirkung auf die Reaktionszeitkosten untersucht. Nikotin zeigte keinen Einfluss auf Distraktionskosten in beiden Studien und auch keine Wirkung auf die P3a Komponente in Experiment 3. In Experiment 4 wurde zus{\"a}tzlich die Wirkung von Nikotin auf das Losl{\"o}sen von Aufmerksamkeit untersucht, indem die Schwierigkeit des Losl{\"o}sens variiert wurde. Auch hier zeigte sich keine Nikotinwirkung. Allerdings konnte in beiden Studien weder die h{\"a}ufig berichtete generelle Reaktionszeitverk{\"u}rzung noch die Verringerung der Kosten invalider Hinweisreize repliziert werden, so dass zum Einen keine Aussage {\"u}ber die Wirkung von Nikotin auf Distraktionen oder den Aufmerksamkeitslosl{\"o}seprozess gemacht werden k{\"o}nnen, zum Anderen sich die Frage stellte, unter welchen Bedingungen Nikotin einen differentiellen Effekt {\"u}berhaupt zeigt. Im letzten Experiment wurde hierzu die H{\"a}ufigkeit der Reaktionsanforderung einerseits und die zeitlichen Aspekte der Aufmerksamkeitslenkung andererseits variiert und der Effekt des Nikotins auf den Validit{\"a}tseffekt, die Reaktionszeitdifferenz zwischen valide und invalide vorhergesagten Zielreizen, betrachtet. Nikotin verringerte bei Individuen, bei denen Aufmerksamkeitslenkung in allen Bedingungen evident war, in der Tendenz den Validit{\"a}tseffekt in der ereignis{\"a}rmsten Bedingung, wenn nur selten willentliche Aufmerksamkeitsausrichtung notwendig war. Dies k{\"o}nnte als Hinweis gedeutet werden, dass Nikotin unter Bedingungen, die große Anforderungen an die Vigilanz stellen, die top-down Zuweisung von Aufmerksamkeitsressourcen unterst{\"u}tzt.},
  subject      = {Nicotin},
  language  = {de}
}
@phdthesis{Ehrlenspiel2006,
  author    = {Ehrlenspiel, Felix},
  title     = {Choking under pressure : attention and motor control in performance situations},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-12377},
  school      = {Universit{\"a}t Potsdam},
  year      = {2006},
  abstract  = {When top sports performers fail or "choke" under pressure, everyone asks: why? Research has identified a number of conditions (e.g. an audience) that elicit choking and that moderate (e.g. trait-anxiety) pressure - performance relation. Furthermore, mediating processes have been investigated. For example, explicit monitoring theories link performance failure under psychological stress to an increase in attention paid to a skill and its step-by-step execution (Beilock \& Carr, 2001). Many studies have provided support for these ideas. However, so far only overt performance measures have been investigated which do not allow more thorough analyses of processes or performance strategies. But also a theoretical framework has been missing, that could (a) explain the effects of explicit monitoring on skill execution and that (b) makes predictions as to what is being monitored during execution. Consequently in this study, the nodalpoint hypothesis of motor control (Hossner \& Ehrlenspiel, 2006) was taken to predict movement changes on three levels of analysis at certain "nodalpoints" within the movement sequence. Performance in two different laboratory tasks was assessed with respect to overt performance (the observable result, for example accuracy in the target), covert performance (description of movement execution, for example the acceleration of body segements) and task exploitation (the utilization of task properties such as covariation). A fake competition (see Beilock \& Carr, 2002) was used to invoke pressure. In study 1 a ball bouncing task in a virtual-reality set-up was chosen. Previous studies (de Rugy, Wei, M{\"u}ller, \& Sternad, 2003) have shown that learners are usually able to "passively" exploit the dynamical stability of the system. According to explicit monitoring theories, choking should be expected either if the task itself evokes an "active control" (Experiment 1) or if learners are provided with explicit instructions (Experiment 2). In both experiments, participants first went through a practice phase on day 1. On day 2, following the Baseline Test participants were divided into a High-Stress or No-Stress Group for the final Performance Test. The High-Stress Group entered a fake competition. Overt performance was measured by the Absolute Error (AE) of ball amplitudes from target height; covert performance was measured by Period Modulation between successive hits and task exploitation was measured by Acceleration (AC) at ball-racket impact and Covariation (COV) of impact parameters. To evoke active control in Exp. 1 (N=20), perturbations to the ball flight were introduced. In Exp. 2 (N=39) half of the participants received explicit skill-focused instructions during learning. For overt performance, results generally show an interaction between Stress Group and Test, with better performance (i. e. lower AE) for the High-Stress group in the final Performance Test. This effect is also independent of the Instructions that participants had received during learning (Exp. 2). Similar effects were found for COV but not for AC. In study 2 a visuomotor tracking task in which participants had to pursuit a target cross that was moving on an invisible curve. This curve consisted of 3 segments of 6 turning points sequentially ordered around the x-axis. Participants learned two short movement sequences which were then concatenated to form a single sequence. It was expected that under pressure, this sequence should "fall apart" at the point of concatenation. Overt Performance was assessed by the Root Mean Square Error between target and pursuit cross as well as the Absolute Error at the turning points, covert performance was measured by the Latency from target to pursuit turning and task exploitation was measured by the temporal covariation between successive intervals between turning points. Experiment 3 (intraindividual variation) as well as Experiment 4 (interindividual variation) show performance enhancement in the pressure situation on the overt level with matching results on covert and task exploitation level. Thus, contrary to previous studies, no choking under pressure was found in any of the experiments. This may be interpreted as a failure in the experimental manipulation. But certainly also important characteristics of the task are highlighted. Choking should occur in tasks where performers do not have the time to use action or thought control strategies, that are more relevant to their "self" and that are discrete in nature.},
  language  = {en}
}