L'objectif de cette thèse est d'étudier le développement des mécanismes sous-tendant l'exploration d'une scène visuelle. Les résultats montrent que les stratégies d'attention ambiante et focale émergent vers l'âge de 12 mois. La saillance détermine davantage les mouvements oculaires chez les enfants de moins de 6 ans que chez les plus âgés. En outre, les objets sémantiquement inconsistants avec le contexte visuel attirent similairement le regard des jeunes enfants et des adultes. Cependant, seuls les enfants sont plus rapidement attirés par les objets à saillance élevée que par ceux à saillance réduite. L'effet du niveau de vocabulaire sur l'analyse des scènes visuelles se trouve uniquement dans la condition objets consistants. Toutefois, la latence et la topographie des PEs sont modulées selon le niveau de vocabulaire. Nos résultats suggèrent que le contrôle des mouvements oculaires liés à l'analyse d'une scène visuelle se développe de la petite enfance jusqu'à l'enfance. Bien que les modes ambiant et focal soient présents durant la petite enfance, l'exploration d'une scène visuelle est surtout influencée par le mode focal. De plus, les jeunes enfants utilisent - semblablement aux adultes - le contexte visuel pour orienter leur attention visuelle. Aux stades précoces du développement, la saillance paraît un facteur déterminant pour l'allocation du regard. L'attention visuelle est également influencée par les compétences linguistiques des jeunes enfants. / This dissertation investigated developmental mechanism underlying scene exploration. The results showed that ambient and focal attention strategies emerge by 12 months of age. Saliency guided eye movements more in children younger than 6 years compared with older children. Additionally, objects that were semantically inconsistent with the scene context equally attracted the gaze in young children and adults. Children were, however, attracted faster to high salient than to low salient objects. High-producers looked longer to consistent objects than low-producers while both groups looked equally long to inconsistent objects. The N400 ERP component was more pronounced for inconsistent than for consistent scene-word pairs. Low-producers exhibited a later N400 effect over the right frontal recording sites while in high-producers the N400 effect was observed earlier over the left frontal sites. Our results suggest that eye movement control during scene viewing mature from infancy to childhood. Even though ambient and focal modes are present in early infancy, scene exploration is dominated by focal mode. Additionally, young children use scene context, similarly to adults, in guidance of their visual attention. However, during early stages of development saliency has a stronger effect on gaze allocation compared with adults. Visual attention was also influenced by linguistic skills in young children.

Recent research makes use of biologically inspired computation and artificial intelligence as efficient means to solve real-world problems. Humans show a significant performance in extracting and interpreting visual information. In the cases where visual data is not available, or, for example, if it fails to provide comprehensive information due to occlusions, tactile exploration assists in the interpretation and better understanding of the environment. This cooperation between human senses can serve as an inspiration to embed a higher level of intelligence in computational models. In the context of this research, in the first step, computational models of visual attention are explored to determine salient regions on the surface of objects. Two different approaches are proposed. The first approach takes advantage of a series of contributing features in guiding human visual attention, namely color, contrast, curvature, edge, entropy, intensity, orientation, and symmetry are efficiently integrated to identify salient features on the surface of 3D objects. This model of visual attention also learns to adaptively weight each feature based on ground-truth data to ensure a better compatibility with human visual exploration capabilities. The second approach uses a deep Convolutional Neural Network (CNN) for feature extraction from images collected from 3D objects and formulates saliency as a fusion map of regions where the CNN looks at, while classifying the object based on their geometrical and semantic characteristics. The main difference between the outcomes of the two algorithms is that the first approach results in saliencies spread over the surface of the objects while the second approach highlights one or two regions with concentrated saliency. Therefore, the first approach is an appropriate simulation of visual exploration of objects, while the second approach successfully simulates the eye fixation locations on objects. In the second step, the first computational model of visual attention is used to determine scattered salient points on the surface of objects based on which simplified versions of 3D object models preserving the important visual characteristics of objects are constructed. Subsequently, the thesis focuses on the topic of tactile object recognition, leveraging the proposed model of visual attention. Beyond the sensor technologies which are instrumental in ensuring data quality, biological models can also assist in guiding the placement of sensors and support various selective data sampling strategies that allow exploring an object’s surface faster. Therefore, the possibility to guide the acquisition of tactile data based on the identified visually salient features is tested and validated in this research. Different object exploration and data processing approaches were used to identify the most promising solution. Our experiments confirm the effectiveness of computational models of visual attention as a guide for data selection for both simplifying 3D representation of objects as well as enhancing tactile object recognition. In particular, the current research demonstrates that: (1) the simplified representation of objects by preserving visually salient characteristics shows a better compatibility with human visual capabilities compared to uniformly simplified models, and (2) tactile data acquired based on salient visual features are more informative about the objects’ characteristics and can be employed in tactile object manipulation and recognition scenarios. In the last section, the thesis addresses the issue of transfer of learning from vision to touch. Inspired from biological studies that attest similarities between the processing of visual and tactile stimuli in human brain, the thesis studies the possibility of transfer of learning from vision to touch using deep learning architectures and proposes a hybrid CNN that handles both visual and tactile object recognition.

A key question in the investigation of awareness is whether it can occur without attention, or vice versa. Most evidence to date suggests that attention is necessary for awareness of visual stimuli, but that attention can sometimes be present without corresponding aware-ness. However, there has been some evidence that natural scenes in general, and in particular scenes including animals, may not require visual attention for a participant to become aware of their gist. One relatively recent paradigm for providing evidence for animal awareness without attention (Li, VanRullen, Koch, & Perona, 2002) requires participants to perform an attention demanding primary task while also determining whether a photograph displayed briefly in the periphery contains an animal as a secondary task. However, Cohen, Alvarez, and Nakayama (2011) questioned whether the primary task in these experiments used up all the available attentional capacity. Their experiments used a more demanding primary task to be sure attention really was not available for the image-recognition task, and the results indicated that attention was contributing to the animal detection task. However, in addition to changing the primary task, they displayed the stimuli for the two tasks superimposed on each other in the same area of the visual field. The experiment reported here is similar to the one by Cohen et al., but with the stimuli for the two tasks separated spatially. Animal recognition with separated stimuli was impaired by additionally performing the attention-demanding task, leaving no good evidence that it is possible to recognize natural scenes without attention, in turn removing this support for awareness without attention.

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The purpose of this study was to determine whether a measure of viewing time that uses non-erotic visual stimuli can differentiate between frequent users and infrequent users of pornography. Thirty-six male participants were classified as infrequent pornography users and 37 as frequent users. Participants completed a questionnaire and were asked to rate a variety of images, both male and female of varying ages, on their sexual attractiveness. Individuals were timed as to how long they looked at each image. The groups were then compared based upon their viewing time of several categories. No statistically significant differences were detected. The temporal stability of the measure was also investigated. Researchers found that for the two groups, high correlations were found with juvenile females and adult females, somewhat strong correlations for small male child and pre-juvenile female, and relatively weak correlations for adult males, small female child, juvenile male, and pre-juvenile male. Researchers also attempted to differentiate the two groups based upon their temporal stability. A statistically significant difference between the groups was found with their viewing times of pre-juvenile females; however, the researchers caution the readers about its interpretation. Researchers concluded that perhaps the viewing time measure used in this study was not sufficiently sensitive enough to differentiate on pornography use. They indicated that perhaps viewing time measures utilizing erotic visual stimuli may be more effective in detecting such a difference. The researchers also speculated that there may be differences between pornography users and non pornography users and that pornography may not be the factor responsible for causing callousness towards women, acceptance of rape myths, and a reduction in sexual and marital satisfaction. The researchers suggested that there may be another factor responsible for causing these negative effects and also predisposes an individual to heavy pornography use.

A biological marker of the addictive state would be a major breakthrough in objectively assessing the efficacy of treatment outcomes. Given its role in the mesolimbic system and drug reward, most biological marker studies for addiction focus on measures related to dopamine (DA). Dopamine is also implicated in some disorders of visual attention and plays a modulatory role in the processing of color in the retinal DA pathway. For example, visual processing in the retina has been shown to co-vary with DA levels during cocaine withdrawal. In this electroencephalographic (EEG) study, we studied event related potentials (ERPs) and reaction time (RT) in opiate addicts—recruited from a community-based high intensity residential substance abuse and detoxification treatment program—and their age- and gender- matched controls. Using a visual color recognition Go/NoGo task with three similar blocks, participants responded in each block to a "Relevant" stimulus of one of three randomly-presented Red, Green or Blue light stimuli as instructed, while ignoring the other two "Irrelevant" stimuli. This simple task produced robust ERPs that were well-differentiated in the visual evoked potentials (VEPs) obtained by the Relevant stimulus compared to the VEPs from Irrelevant distractor stimuli. P300 ERP amplitudes from the color recognition task were significantly higher in males than females. Similar results were obtained with the frontal late positive (LP) potentials (i.e., 700 msec after stimulus onset), which occurred 200-300 msec after the average participant response/RT. While there were no significant RT differences between controls and addicts in the task, male controls had significantly greater P300 and LP potentials than female controls, suggesting sex differences in visual color processing. However, there were also significant differences in P300 amplitudes male controls and addiction participants—suggesting a difference in retinal DA production in opiate addiction. Further to the hypothesis of sex differences in visual color processing, P300s and LPs were not significantly different in female controls compared to female addicts. Changing the color wavelength of the Relevant stimulus did not significantly affect ERPs in males or females, controls or addicts at P300 but did at LP, particularly when the color blue was relevant. These findings suggest that there are significant sex differences in retinal DA production for opiate addicts and controls in visual processing for a simple Go/NoGo color recognition task.

The engagement in multiple activities in the workplace leads to the challenge of managing several tasks. When managing multiple tasks, it may be difficult to remember to complete all tasks. Within an operations team at a hedge fund, there are demands that all trades are reported by the end of the day to the correct prime brokerage. This thesis examines the research question: How can a GUI be designed to remind and aid users to verify that trade information has been managed correctly? The research was conducted at a financial company, and focused on improving the workflow for one of the company’s clients and its operations team. To identify the challenges of a financial operator, contextual inquiries were conducted, followed by a design workshop to generate design ideas. The results were used as inspiration for the prototype of a GUI. The prototype was evaluated through cognitive walkthroughs, expert review, and with end users. The prototype was found to aid financial operators to verify if there was any work left, but the reminder aspect would need to be examined with a real system during an extended period. / Att engagera sig i flertalet aktiviteter på en arbetsplats leder till utmaningen att hantera många uppgifter. När det finns många uppgifter att hantera, kan det vara svårt att komma ihåg att slutföra alla uppgifter. Inom ett operationsteam på en hedgefond finns krav att alla värdepappersaffärer ska vara rapporterade innan dagens slut till rätt huvudmäklarfirma (prime brokerage). Denna uppsats undersöker forskningsfrågan: Hur kan ett GUI designas för att påminna och underlätta för användaren att verifiera att information om värdepappersaffärer har hanterats korrekt? Forskningen genomfördes på ett finansiellt företag och fokuserade på att underlätta arbetsflödet för en av företagets kunder och dess operationsteam. För att identifiera utmaningarna för en finansiell operatör genomfördes kontextuella intervjuer, vilka följdes av en designworkshop för att generera designidéer. Resultaten användes som inspiration till en prototyp för ett GUI. Prototypen utvärderades genom kognitiv genomgång (cognitive walkthrough), expertgranskning och med slutanvändare. Prototypen ansågs underlätta för finansiella operatörer att verifiera om det fanns kvarvarande uppgifter, men påminnelseaspekten skulle behöva undersökas ytterligare med ett fullt utvecklat system under en längre period.

No / In this paper, we investigate how controlled changes to image properties and orientation affect eye movements for repeated viewings of images of natural scenes. We make changes to images by manipulating low-level image content (such as luminance or chromaticity) and/or inverting the image. We measure the effects of these manipulations on human scanpaths (the spatial and chronological path of fixations), additionally comparing these effects to those predicted by a widely used saliency model (L. Itti & C. Koch, 2000). Firstly we find that repeated viewing of a natural image does not significantly modify the previously known repeatability (S. A. Brandt & L. W. Stark, 1997; D. Noton & L. Stark, 1971) of scanpaths. Secondly we find that manipulating image features does not necessarily change the repeatability of scanpaths, but the removal of luminance information has a measurable effect. We also find that image inversion appears to affect scene perception and recognition and may alter fixation selection (although we only find an effect on scanpaths with the additional removal of luminance information). Additionally we confirm that visual saliency as defined by L. Itti and C. Koch's (2000) model is a poor predictor of real observer scanpaths and does not predict the small effects of our image manipulations on scanpaths.

This dissertation explores how children with and without developmental coordination disorder (DCD) ‘look’ and ‘see’: how they integrate vision and attention to guide arm and hand movements during a visuomotor task. Chapter 1 provides the thesis context, reviewing the vision and attention literature, outlining the role of these processes in motor performance, and reviewing what is known about vision and attention in children with DCD. Chapter 1 includes a discussion on eye tracking to measure visual attention, and outlines the thesis purpose and objectives.Chapter 2 focuses on children with DCD, detailing their presentation and clinical management. This chapter serves to increase the reader’s understanding of the difficulties children with DCD experience, and to demonstrate the need for intervention to prevent the profound consequences that can impact their quality of life. Chapter 3 presents a study that explores how children with and without DCD employ vision and attention to accomplish a visuomotor task in a natural setting, using a novel eye tracking design. Highlighted here are important differences during visuomotor task performance: compared to their peers, children with DCD did not use predictive gaze to attend to relevant task objects, but rather used vision to guide their arm/hand throughout the task. Chapter 4 outlines lessons learned from using an eye tracker with children with DCD, describing the children for whom eye tracking was not reliable, and discussing equipment and participant factors that impact eye tracker use. Recommendations for future research using eye tracking with the DCD population are provided. Finally, Chapter 5 discusses the clinical and research implications of the studies conducted here. Insights gained regarding visual attention differences between children with and without DCD are discussed in the context of interventions to improve health outcomes in children with DCD and the design of future eye tracking studies. / Dissertation / Doctor of Philosophy (PhD)

Visual cues are a technique used for the purposes of guiding a viewer towards points of interest. Most commonly this is done with the use of color and contrast to make objects stick out more from its environment. Within the context of video games, visual cues are implemented to guide player actions in otherwise complex scenarios. Due to the steady increase of high-fidelity graphics in video games, visual cues are becoming more important for players so that visual clarity can still be maintained. In the video games analyzed in this thesis this is primarily done by adding a glowing outline (highlight) around the object or entity that the game designers want the player to interact with. Thus, this thesis attempts to explore two different qualities of visual cues: color and glow intensity, to see their effects on player performance and experience. To do this, an experiment was conducted in a scaled-down version of an FPS game with the purpose of testing these different qualities in four different scenarios and how they may influence both reaction time and player satisfaction. The results from this study indicate that neither of the tested qualities had any significant impact on a participant’s ability to complete their task. On the other hand: color had a big effect on player experience where one color, purple, was deemed irritating by most participants. Finally, the differences in glow intensity went unnoticed in most of the tested scenarios which points towards color being the more important quality of the ones tested in this study.