An attentional template based on a feature in visual working memory (VWM) can be used to bias attention toward feature-matching objects in the visual field. Attentional guidance based on a single feature is highly efficient and has been well characterized. It is debated, however, whether multiple features can be used to guide attention simultaneously. Some argue that only a single feature in VWM can be elevated to an “active” state and influence perceptual selection. To evaluate whether multiple features can guide attention simultaneously, eye movements were recorded while participants completed both traditional and gaze-contingent visual search tasks. Participants demonstrated guidance by multiple features by switching between relevant colors frequently and without delay. Furthermore, relevant objects of different colors actively competed for saccadic selection. These results provide compelling evidence that multiple attentional templates are able to guide selection simultaneously. Although it was originally proposed that a feature in VWM could also be used to bias attention away from irrelevant items (“template for rejection”), the evidence thus far has been mixed. Some studies report that participants were faster to find a target item after being cued with a distractor feature, suggesting participants were using this feature to avoid matching items, while other studies report a cost and find that participants actually attended to cue-matching items even though they are irrelevant. The current work demonstrates that some evidence in support of feature-guided avoidance can be explained by spatially recoding the cued feature information. Furthermore, when shown a distractor color at the beginning of a trial, participants frequently fixated a matching object early in the trial, but avoided matching objects later in the trial. Other work has suggested that this initial attentional capture by a cue-matching object facilitates later avoidance, but the current data do not support a functional relationship of this nature. In sum, it may not be possible to implement an exclusionary template directly as feature-guided avoidance, but it may be possible to implement indirectly by converting the irrelevant feature information into relevant feature or spatial information.

<p>MobileMe is a recently developed system for monitoring and recording physiological variables. It is wireless, and can therefore be suitable for field research, for example when measuring motion sickness symptoms.</p><p>The aim of this thesis was to conclude whether the MobileMe recording system was valid for research studies. A validation study, consisting of two parts and including 10 subjects, was performed. The first part was a laboratory study, where data from MobileMe and a reference equipment were compared. A field study was also performed, onboard a combat boat, to determine the equipment’s validity in uncontrolled environments. Furthermore, the field study included an investigation of motion sickness symptoms, and provided data for evaluation of motion sickness rating scales.</p><p>Statistical results from the laboratory study, and results from evaluation of data from the field study, showed that MobileMe was valid in both controlled and uncontrolled environments.</p>

Dichoptic presentation of vernier stimuli, i.e., one segment to each eye, yielded three times higher thresholds than binocular presentation, mainly due to uncorrelated movements of both eyes. Thresholds allow one to calculate an upper estimate for the amplitudes of uncorrelated eye movements during fixation. This estimate matches the best results from direct eye position recording, with the calculated mean amplitude of eye tremor corresponding to roughly one photoreceptor diameter. The combined amplitude of both correlated and uncorrelated eye movements was also measured by delaying one segment of the vernier relative to its partner under monocular or dichoptic conditions.

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. / Die kognitive Psychologie beschäftigt sich traditionell mit dem Zusammenspiel von Wahrnehmung, Kognition und Verhaltenssteuerung. Die Untersuchung von Blickbewegungen beim Lesen bildet dabei ein Forschungsfeld, in dem die Prozesse und Interaktionen dieser Subsysteme in einem klar definierten Rahmen untersucht werden können. Dabei geht es speziell um die Frage, wie viel Information visuell wahrgenommen wird, wie die kognitive Weiterverarbeitung der visuellen Buchstabeninformation über lexikalische Wortverarbeitung hin zu einem inhaltlichen Satzverständnis zeitlich koordiniert ist, und wie sich diese Prozesse auf das Verhalten – die Steuerung der Blickbewegung – auswirken. Verschiedene Modelle zur Erklärung des spezifischen Blickbewegungsverhaltens beim Lesen wurden vorgeschlagen (für einen Überblick siehe Reichle, Rayner, & Pollatsek, 2003). Einige Modelle basieren auf der Annahme serieller Aufmerksamkeitsverschiebung von Wort zu Wort, wohingegen andere verteilte Aufmerksamkeit auf eine Region mehrerer Wörter im Satz gleichzeitig annehmen. Da Aufmerksamkeit eng mit der eigentlichen Wortverarbeitung assoziiert ist, besteht ein wesentlicher Unterschied zwischen den Modellen darin, dass die eigentlichen Wortverarbeitungsprozesse entweder ebenfalls strikt seriell oder parallel erfolgen. Trotz solch entscheidender Unterschiede im zeitlichen Verlauf der Wortverarbeitung können beide Modellklassen viele der Benchmark-Effekte beim Lesen hinreichend erklären. Tatsächlich scheint es nicht viel empirische Evidenz zu geben, die die Grundannahmen der Modelle falsifizieren könnte. Die Frage, ob und wie noch nicht direkt angesehene Wörter rechts der Fixation die Blickbewegung beeinflussen, wird in der Debatte über serielle oder parallele Wortverarbeitung oft als entscheidend betrachtet. Insbesondere wird diskutiert, bis zu welcher Entfernung parafoveale Wörter vorverarbeitet werden und wie das die gegenwärtige und folgende Wortverarbeitung beeinflusst. In einer Serie von vier Leseexperimenten wurde die Vorverarbeitung von Wörtern an den Grenzen der Wahrnehmungsspanne untersucht. Die vorliegende Arbeit versucht zudem, über einen einfachen Existenzbeweis der Vorverarbeitung von Wörtern in solchen Distanzen hinaus zu gehen. Mit einer Manipulation, die verschiedene Quellen solcher weitreichenden Vorverarbeitungseffekte dissoziiert, können Nutzen und Kosten der parafovealen Vorschau in einer einzigen Analyse untersucht und über eine Zielregion von drei Wörtern hinweg verfolgt werden. Dieselbe Manipulation überprüft gleichzeitig die Rolle okulomotorischer Fehler als Ursache für nicht lokale, verteilte Effekte beim Lesen. Die Ergebnisse tragen zu einem differenzierteren Verständnis der Wortverarbeitung in der Wahrnehmungsspanne und der zeitlich-räumlichen Verteilung der Aufmerksamkeit beim Lesen bei.

When the eyes fixate at a point in a visual scene, small saccades rapidly shift the image on the retina. The effect of these microsaccades on the latency of subsequent large-scale saccades may be twofold. First, microsaccades are associated with an enhancement of visual perception. Their occurrence during saccade target perception should, thus, decrease saccade latencies. On the other hand, microsaccades likely indicate activity in fixation-related oculomotor neurons. These represent competitors to saccade-related cells in the interplay of gaze holding and shifting. Consequently, an increase in saccade latencies after microsaccades would be expected. Here, we present evidence for both aspects of microsaccadic impact on saccade latency. In a delayed response task, participants made saccades to visible or memorized targets. First, microsaccade occurrence up to 50 ms before target disappearance correlated with 18 ms (or 8%) faster saccades to memorized targets. Second, if microsaccades occurred shortly (i.e., < 150 ms) before a saccade was required, saccadic reaction times in visual and memory trials were increased by about 40 ms (or 16%). Hence, microsaccades can have opposite consequences for saccade latencies, pointing at a differential role of these fixational eye movements in preparation of motor programs.

Reading involves the dynamic construction of a mental model corresponding to the situation described in a text. This representation draws on the semantic and grammatical content of the text and also involves inferences for unstated information and the sequencing of events in time. In the current study, an eye-tracking methodology was used to explore the critical role of grammatical aspect in this process. The results showed that, following an event expressed in imperfective aspect, the reading of a necessarily later event was slowed compared to when the earlier event was expressed in perfective aspect. However, the effect depended on world knowledge—when the first event was typically of short duration, it did not evoke an "ongoing" interpretation to the same degree compared to when it was of long duration. The results highlight comprehenders' use of world knowledge and subtle grammatical cues in the representation of event information during on-line reading.

Reading involves the dynamic construction of a mental model corresponding to the situation described in a text. This representation draws on the semantic and grammatical content of the text and also involves inferences for unstated information and the sequencing of events in time. In the current study, an eye-tracking methodology was used to explore the critical role of grammatical aspect in this process. The results showed that, following an event expressed in imperfective aspect, the reading of a necessarily later event was slowed compared to when the earlier event was expressed in perfective aspect. However, the effect depended on world knowledge—when the first event was typically of short duration, it did not evoke an "ongoing" interpretation to the same degree compared to when it was of long duration. The results highlight comprehenders' use of world knowledge and subtle grammatical cues in the representation of event information during on-line reading.

MobileMe is a recently developed system for monitoring and recording physiological variables. It is wireless, and can therefore be suitable for field research, for example when measuring motion sickness symptoms. The aim of this thesis was to conclude whether the MobileMe recording system was valid for research studies. A validation study, consisting of two parts and including 10 subjects, was performed. The first part was a laboratory study, where data from MobileMe and a reference equipment were compared. A field study was also performed, onboard a combat boat, to determine the equipment’s validity in uncontrolled environments. Furthermore, the field study included an investigation of motion sickness symptoms, and provided data for evaluation of motion sickness rating scales. Statistical results from the laboratory study, and results from evaluation of data from the field study, showed that MobileMe was valid in both controlled and uncontrolled environments.

Purpose: The aim of the study was to delineate differences in saccade characteristics between a population of athletes and non athletes. Aspects specifically investigated were latency, accuracy, peak velocity, and gain adaptation of saccades using both increasing and decreasing paradigms. Methods: A sample of 28 athletes (varsity badminton and squash players) and 18 non athletes (< 3 hour/week in sports) were studied. Eye movements were recorded at 120Hz using a video based eye tracker (ELMAR 2020). Each subject participated in 2 sessions on separate days. Baseline saccade responses to dot stimuli were measured in both sessions (stimulus size: 5-25 deg). The first session involved a gain decreasing paradigm, induced by displacing the stimulus backwards by 3 degrees from the initial target step (12 deg) for 500 trials. In the 2nd session a gain increase was induced by displacing the stimuli by 3 degrees in the forward direction. The latency and accuracy were calculated from the baseline. The asymptotic peak velocity was calculated from the main sequence (amplitude vs. peak velocity). The amplitude gains, calculated from the adaptation phase, were averaged for every 100 saccade responses. The averaged gains were normalized with respect to the baseline, fitted with a 3rd order polynomial, and differentiated to obtain the rate of change. Differences between the groups were compared using a regression analysis. Results: There were no significant differences in latency, accuracy, and asymptotic peak velocity between athletes and non athletes. No significant differences were seen between the two groups in the magnitude of saccadic adaptation, both for decreasing (- 15% in both groups) and increasing (athletes + 7% and non athletes + 5%) paradigms. However, athletes showed a significantly faster rate of adaptation for the gain increasing paradigm (F = 17. 96[3,6]; p = 0. 002). A significant difference was not observed in the rate of adaptation for the gain decreasing adaptation (F = 0. 856[3,6]; p = 0. 512). Conclusions: The study showed that the athletes do not respond better in terms of reaction time or accuracy of saccades. The significant difference in the rate of change of adaptation between the groups shows that online modification of saccades in the positive direction, although not greater in magnitude, occurs quicker in athletes than non athletes.

Mit der wachsenden Notwendigkeit zur Zusammenarbeit von Personen an unterschiedlichen Standorten gewinnt eine effektive Gestaltung technisch mediierter Kommunikation an Bedeutung. Ein wesentliches Problem liegt dabei darin, nonverbale Kommunikationsinhalte so zu übertragen, dass klare Bezüge zwischen der Aufmerksamkeit des Partners und den gemeinsamen Arbeitsobjekten hergestellt werden können. Da Blickbewegungen einen räumlich und zeitlich hochauflösenden Zugang zu Aufmerksamkeitsprozessen ermöglichen, kann ihre Übertragung als Cursor auf dem Bildschirm des Partners zu Verbesserungen im gegenseitigen Verständnis und damit auch der kooperativen Leistung führen. Eine detaillierte Untersuchung der Wirkweise von Blickfeedback und vor allem ein kritischer Vergleich mit herkömmlichen Formen der Cursorübertragung stehen jedoch noch aus. In drei Studien mit insgesamt sechs Experimenten wurde in dieser Dissertation untersucht, wie sich eine Blickübertragung auf den Prozess der technisch mediierten Kommunikation auswirken kann. In der ersten Studie nutzten Personen ihren Blick zur Kommunikation von Bildinhalten. Es wurde geprüft, wie sich Blickparameter im Rahmen einer solchen intentional-kommunikativen Verwendung von Blickbewegungen unterscheiden, die lediglich der Aufnahme von Informationen dienen. Dieser Vergleich wurde bei freier Bildbetrachtung sowie im Rahmen einer restriktiver definierten Aufgabe durchgeführt, in der zu beachtende Bereiche vorab definiert waren. Die zweite Studie kontrastiert im Kontext von Puzzleaufgaben die Übertragung des Partnerblickes mit einer rein verbalen Interaktion und der Rückmeldung seiner Mausbewegungen. Während die Interaktivität zwischen den Partnern variiert wurde, standen sowohl Aufgabenleistung als auch der kommunikative Prozess an sich im Fokus der Untersuchungen. Zu diesem Zwecke wurden verbale Äußerungen der Partner, einzelne Handlungen auf dem Weg zur Lösung und Parameter der Blickbewegungen betrachtet. In der dritten Studie wurde der übertragene Blick genutzt, um mithilfe eines beweglichen Fensters diejenigen Bildbereiche sichtbar zu machen, die der Partner zur Lösung benötigte. Blickübertragung wurde auch hier mit dem Mauszeigen verglichen. Dabei wurde die Sichtbarkeit aufgabenrelevanter Objekte für den fensterverschiebenden Assistenten variiert und geprüft, wie sich dies auf die Koordination gemeinsamer Handlungen unter Verwendung beider Cursortypen auswirkte. Insgesamt zeigen die Ergebnisse, dass eine kommunikative Nutzung von Blickbewegungen in visuell-räumlichen Aufgaben zu Leistungsverbesserungen im Vergleich zur rein sprachlichen Kommunikation führen kann. Verglichen mit der Mausübertragung geht Blickübertragung mit einer geringeren Sicherheit über die Cursorintention und die damit verbundene Handlungsrelevanz des Blickes einher. Dieses Problem besteht vor allem in interaktiven, weniger strukturierten Aufgaben und in Situationen, in denen der Partnerblick nicht zu den Objekten in Bezug gesetzt werden kann, auf die er sich bezieht. Anhand der Ergebnisse werden Potentiale und Schwierigkeiten in der Übertragung von Blickbewegungen diskutiert. Es werden Vorschläge unterbreitet, in welchen Kontexten ihr Einsatz zur Verbesserung der technisch mediierten Kommunikation sinnvoll sein kann und was bei der Gestaltung solcher Anwendungen beachtet werden sollte.