TY - JOUR A1 - Rothkegel, Lars Oliver Martin A1 - Trukenbrod, Hans Arne A1 - Schütt, Heiko Herbert A1 - Wichmann, Felix A. A1 - Engbert, Ralf T1 - Temporal evolution of the central fixation bias in scene viewing JF - Journal of vision N2 - When watching the image of a natural scene on a computer screen, observers initially move their eyes toward the center of the image—a reliable experimental finding termed central fixation bias. This systematic tendency in eye guidance likely masks attentional selection driven by image properties and top-down cognitive processes. Here, we show that the central fixation bias can be reduced by delaying the initial saccade relative to image onset. In four scene-viewing experiments we manipulated observers' initial gaze position and delayed their first saccade by a specific time interval relative to the onset of an image. We analyzed the distance to image center over time and show that the central fixation bias of initial fixations was significantly reduced after delayed saccade onsets. We additionally show that selection of the initial saccade target strongly depended on the first saccade latency. A previously published model of saccade generation was extended with a central activation map on the initial fixation whose influence declined with increasing saccade latency. This extension was sufficient to replicate the central fixation bias from our experiments. Our results suggest that the central fixation bias is generated by default activation as a response to the sudden image onset and that this default activation pattern decreases over time. Thus, it may often be preferable to use a modified version of the scene viewing paradigm that decouples image onset from the start signal for scene exploration to explicitly reduce the central fixation bias. KW - eye movements KW - dynamic models KW - visual scanpath KW - visual attention Y1 - 2017 U6 - https://doi.org/10.1167/17.13.3 SN - 1534-7362 VL - 17 SP - 1626 EP - 1638 PB - Association for Research in Vision and Opthalmology CY - Rockville ER - TY - THES A1 - Rothkegel, Lars Oliver Martin T1 - Human scanpaths in natural scene viewing and natural scene search T1 - Menschliche Blickspuren beim Betrachten und Durchsuchen natürlicher Szenen BT - the role of systematic eye-movement tendencies N2 - Understanding how humans move their eyes is an important part for understanding the functioning of the visual system. Analyzing eye movements from observations of natural scenes on a computer screen is a step to understand human visual behavior in the real world. When analyzing eye-movement data from scene-viewing experiments, the impor- tant questions are where (fixation locations), how long (fixation durations) and when (ordering of fixations) participants fixate on an image. By answering these questions, computational models can be developed which predict human scanpaths. Models serve as a tool to understand the underlying cognitive processes while observing an image, especially the allocation of visual attention. The goal of this thesis is to provide new contributions to characterize and model human scanpaths on natural scenes. The results from this thesis will help to understand and describe certain systematic eye-movement tendencies, which are mostly independent of the image. One eye-movement tendency I focus on throughout this thesis is the tendency to fixate more in the center of an image than on the outer parts, called the central fixation bias. Another tendency, which I will investigate thoroughly, is the characteristic distribution of angles between successive eye movements. The results serve to evaluate and improve a previously published model of scanpath generation from our laboratory, the SceneWalk model. Overall, six experiments were conducted for this thesis which led to the following five core results: i) A spatial inhibition of return can be found in scene-viewing data. This means that locations which have already been fixated are afterwards avoided for a certain time interval (Chapter 2). ii) The initial fixation position when observing an image has a long-lasting influence of up to five seconds on further scanpath progression (Chapter 2 & 3). iii) The often described central fixation bias on images depends strongly on the duration of the initial fixation. Long-lasting initial fixations lead to a weaker central fixation bias than short fixations (Chapter 2 & 3). iv) Human observers adjust their basic eye-movement parameters, like fixation dura- tions and saccade amplitudes, to the visual properties of a target they look for in visual search (Chapter 4). v) The angle between two adjacent saccades is an indicator for the selectivity of the upcoming saccade target (Chapter 4). All results emphasize the importance of systematic behavioral eye-movement tenden- cies and dynamic aspects of human scanpaths in scene viewing. N2 - Die Art und Weise, wie wir unsere Augen bewegen, ist ein bedeutender Aspekt des visuellen Systems. Die Analyse von Augenbewegungen beim Betrachten natürlicher Szenen auf einem Bildschirm soll helfen, natürliches Blickverhalten zu verstehen. Durch Beantwortung der Fragen wohin (Fixationsposition), wie lange (Fixationsdauern) und wann (Reihenfolge von Fixationen) Versuchspersonen auf einem Bild fixieren, lassen sich computationale Modelle entwickeln, welche Blickspuren auf natürlichen Bildern vorhersagen. Modelle sind ein Werkzeug, um zugrunde liegende kognitive Prozesse, insbesondere die Zuweisung visueller Aufmerksamkeit, während der Betrachtung von Bildern zu verstehen. Das Ziel der hier vorliegenden Arbeit ist es, neue Beitr¨age zur Modellierung und Charakterisierung menschlicher Blickspuren auf natürlichen Szenen zu liefern. Speziell systematische Blicksteuerungstendenzen, welche größtenteils unabhängig vom betrachteten Bild sind, sollen durch die vorliegenden Studien besser verstanden und beschrieben werden. Eine dieser Tendenzen, welche ich gezielt untersuche, ist die Neigung von Versuchspersonen, die Mitte eines Bildes häufiger als äußere Bildregionen zu fixieren. Außerdem wird die charakteristische Verteilung der Winkel zwischen zwei aufeinanderfolgenden Sakkaden systematisch untersucht. Die Ergebnisse dienen der Evaluation und Verbesserung des SceneWalk Modells für Blicksteuerung aus unserer Arbeitsgruppe. Insgesamt wurden 6 Experimente durchgeführt, welche zu den folgenden fünf Kernbefunden führten: i) Ein örtlicher inhibition of return kann in Blickbewegungsdaten von Szenenbetrachtungsexperimenten gefunden werden. Das bedeutet, fixierte Positionen werden nach der Fixation für einen bestimmten Zeitraum gemieden (Kapitel 2). ii) Die Startposition der Betrachtung eines Bildes hat einen langanhaltenden Einfluss von bis zu fünf Sekunden auf die nachfolgende Blickspur (Kapitel 2 & 3). iii) Die viel beschriebene zentrale Fixationstendenz auf Bildern hängt davon ab, wie lange die erste Fixation dauert. Lange initiale Fixationen führen zu deutlich geringerer zentraler Fixationstendenz als kurze Fixationen (Kapitel 2 & 3). iv) Menschliche Betrachter passen Fixationsdauern und Sakkadenamplituden an die visuellen Eigenschaften eines Zielreizes in visueller Suche an (Kapitel 4). v) Der Winkel zwischen zwei Sakkaden ist ein Indikator dafür, wie selektiv das Ziel der zweiten Sakkade ist (Kapitel 4). Alle Ergebnisse betonen die Wichtigkeit von systematischem Blickbewegungsverhalten und dynamischen Aspekten menschlicher Blickspuren beim Betrachten von natürlichen Szenen. KW - eye movements KW - scene viewing KW - computational modeling KW - scanpaths KW - visual attention KW - Augenbewegungen KW - Szenenbetrachtung KW - Computationale Modellierung KW - Blickspuren KW - Visuelle Aufmerksamkeit Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-420005 ER - TY - JOUR A1 - Sekerina, Irina A. A1 - Sauermann, Antje T1 - Visual attention and quantifier-spreading in heritage Russian bilinguals JF - Second language research N2 - It is well established in language acquisition research that monolingual children and adult second language learners misinterpret sentences with the universal quantifier every and make quantifier-spreading errors that are attributed to a preference for a match in number between two sets of objects. The present Visual World eye-tracking study tested bilingual heritage Russian-English adults and investigated how they interpret of sentences like Every alligator lies in a bathtub in both languages. Participants performed a sentence-picture verification task while their eye movements were recorded. Pictures showed three pairs of alligators in bathtubs and two extra objects: elephants (Control condition), bathtubs (Overexhaustive condition), or alligators (Underexhaustive condition). Monolingual adults performed at ceiling in all conditions. Heritage language (HL) adults made 20% q-spreading errors, but only in the Overexhaustive condition, and when they made an error they spent more time looking at the two extra bathtubs during the Verb region. We attribute q-spreading in HL speakers to cognitive overload caused by the necessity to integrate conflicting sources of information, i.e. the spoken sentences in their weaker, heritage, language and attention-demanding visual context, that differed with respect to referential salience. KW - eye-tracking KW - heritage language KW - quantifier-spreading KW - Russian KW - universal quantifiers KW - visual attention Y1 - 2015 U6 - https://doi.org/10.1177/0267658314537292 SN - 0267-6583 SN - 1477-0326 VL - 31 IS - 1 SP - 75 EP - 104 PB - Sage Publ. CY - London ER - TY - JOUR A1 - Kliegl, Reinhold A1 - Wei, Ping A1 - Dambacher, Michael A1 - Yan, Ming A1 - Zhou, Xiaolin T1 - Experimental effects and individual differences in linear mixed models estimating the relationship between spatial, object, and attraction effects in visual attention JF - Frontiers in psychology N2 - Linear mixed models (LMMs) provide a still underused methodological perspective on combining experimental and individual-differences research. Here we illustrate this approach with two-rectangle cueing in visual attention (Egly et al., 1994). We replicated previous experimental cue-validity effects relating to a spatial shift of attention within an object (spatial effect), to attention switch between objects (object effect), and to the attraction of attention toward the display centroid (attraction effect), also taking into account the design-inherent imbalance of valid and other trials. We simultaneously estimated variance/covariance components of subject-related random effects for these spatial, object, and attraction effects in addition to their mean reaction times (RTs). The spatial effect showed a strong positive correlation with mean RT and a strong negative correlation with the attraction effect. The analysis of individual differences suggests that slow subjects engage attention more strongly at the cued location than fast subjects. We compare this joint LMM analysis of experimental effects and associated subject-related variances and correlations with two frequently used alternative statistical procedures. KW - linear mixed model KW - individual differences KW - visual attention KW - spatial attention KW - object-based attention Y1 - 2011 U6 - https://doi.org/10.3389/fpsyg.2010.00238 SN - 1664-1078 VL - 2 PB - Frontiers Research Foundation CY - Lausanne ER - TY - GEN A1 - Kliegl, Reinhold A1 - Wei, Ping A1 - Dambacher, Michael A1 - Yan, Ming A1 - Zhou, Xiaolin T1 - Experimental effects and individual differences in linear mixed models: Estimating the relationship between spatial, object, and attraction effects in visual attention N2 - Linear mixed models (LMMs) provide a still underused methodological perspective on combining experimental and individual-differences research. Here we illustrate this approach with two-rectangle cueing in visual attention (Egly et al., 1994). We replicated previous experimental cue-validity effects relating to a spatial shift of attention within an object (spatial effect), to attention switch between objects (object effect), and to the attraction of attention toward the display centroid (attraction effect), also taking into account the design-inherent imbalance of valid and other trials. We simultaneously estimated variance/covariance components of subject-related random effects for these spatial, object, and attraction effects in addition to their mean reaction times (RTs). The spatial effect showed a strong positive correlation with mean RT and a strong negative correlation with the attraction effect. The analysis of individual differences suggests that slow subjects engage attention more strongly at the cued location than fast subjects. We compare this joint LMM analysis of experimental effects and associated subject-related variances and correlations with two frequently used alternative statistical procedures T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 236 KW - linear mixed model KW - individual differences KW - visual attention KW - spatial attention KW - object-based attention Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-56859 ER -