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This dissertation investigated the effects of complex backgrounds on mental rotation. Stimulus familiarity and background familiarity were manipulated. It systematically explored how familiarizing participants to objects and complex backgrounds affects their performance on a mental rotation task involving complex backgrounds. This study had 113 participants recruited through the UCF Psychology SONA system. Participants were familiarized with a stimulus in a task where they were told to distinguish the stimulus from 3 other stimuli. A similar procedure was used to familiarize the backgrounds. The research design was a 2 stimulus familiarity (Familiarized with the Target Stimulus, not familiarized with the Target Stimulus) by 2 background familiarity (Familiarized with Target Background, not familiarized with Target Background 1) by 2 stimulus response condition (Target Stimulus, Non-Target Stimulus) by 3 background response condition (Target Background, Non-Target Background, Blank Background) by 12 degree of rotation (0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330) mixed design. The study utilized target stimulus and target background familiarity conditions as the between-subjects variables. Background, stimulus, and degree of rotation were within-subjects variables. The participants' performance was measured using reaction time and percent of errors. Reaction time was computed using only the correct responses. After the familiarization task, participants engaged in a mental rotation task featuring stimuli and backgrounds that were present or not present in the familiarization task. A 2 (stimulus familiarization condition) by 2 (background familiarization condition) by 2 (stimulus response condition) by 3 (background response condition) by 12 (degree of rotation) mixed ANOVA was computed utilizing reaction time and percent of errors. Results suggest that familiarity with the Target Background had the largest effect on improving performance across response conditions. The results also suggest that familiarity with both the Target Stimulus and Target Background promoted inefficient mental rotation strategies which resulted in no significant differences between participants familiarized with neither the Target Stimulus nor the Target Background. Theoretical conclusions are drawn about stimulus familiarity and background familiarity. Future studies should investigate the effects of long term familiarity practice on mental rotation and complex backgrounds.

Kangaroo rats (Dipodomys spp.) are frequently characterized as keystone species for their role in altering soil characteristics, changing habitat structure through seed consumption and dispersal, and being important primary consumers in their ecosystem. They are arid adapted and known to forage in areas with sparse vegetation. Studies suggests densely vegetated habitat to be unsuitable for kangaroo rats because plants are an impediment to their locomotion and predator avoidance behaviors. This study focuses on an invasive grass, South African Veldt (Ehrharta calycina), that converts landscapes with sparse vegetation into dense grassland habitats, and the Lompoc kangaroo rat (Dipodomys heermanni arenae) that occupies some of those modified landscapes. I explored the proximate effects of Veldt grass by assessing the locomotion of D.h. arenae in three Veldt grass densities. I hypothesized that Veldt grass influences kangaroo rat locomotion, but that performance could also be influenced by experience with the grass. Kangaroo rats with long-term experience with Veldt grass (i.e., those occupying a habitat containing Veldt grass) and short-term experience (two-night habituation in an artificial Veldt grass patch) were tested by pursing the animals through runways of different grass densities and measuring the amount of time spent crossing the runway, amount of time spent stopped, average velocity, and amount of motivation required to initiate and sustain movement. I also monitored habitat use during the two-night habituation period in order to assess habitat utilization among three Veldt grass density habitat patches. I hypothesized that Veldt grass may influence normal habitat utilization patterns in D.h. arenae: specifically, the avoidance of the densest habitats and preference or disproportionate utilization of the most open habitat. I found, when the animals were left alone to forage and explore, they spent significantly more time in habitat patches containing Veldt grass than in a control patch containing zero percent cover. However, in locomotion trials, Veldt grass had a negative effect on locomotory performance. These effects seem to scale with grass density, and were ameliorated to some degree by familiarization: animals from a Veldt grass habitat of origin performed better in novel Veldt grass templates than animals from a non-Veldt habitat of origin; however, both groups performed equally well after two nights’ habituation to the templates. These results suggest that learning occurred in two nights and that it increased the kangaroo rats’ ability to locomote through the grass when pursued. I note that performance studies often do not take into account the amount of motivation employed to initiate and sustain running of the test animals, and suggest that this be considered in future studies. Furthermore, the learning capacity of a kangaroo rat, as well as a community level perspective that considers neutral or even positive trophic interactions among natives and invasives, must be considered in conservation and management decisions in the future.

The task of navigating and orienting oneself in an unknown environment might seem arbitrary to most people. For a person with a visual impairment however, it can prove to be a challenge. Much research has been conducted to provide useful software solutions to aid this problem. Nevertheless, not enough research has been put into studying the use of our everyday sounds for such software. The present thesis is aimed at evaluating the usefulness of utilising diegetic spatial audio. After a real environment was replicated in a virtual audio environment without visual input, 16 sound students from the University of Skövde were asked to perform the same set of tasks in the virtual and the real environment. The results indicated that diegetic spatial audio is an important part of navigating without vision and that the experiment would be interesting to perform on a larger scale with visually impaired participants.

The present Thesis explored spatial reorientation behaviour of three species of fish (the zebrafish Danio rerio, the redtail splitfin fish Xenotoca eiseni, the goldfish Carassius auratus) and one species of reptiles (the Hermann tortoise Testudo hermanni) to widely assess three issues: 1) the use of environmental geometry with and without landmarks; 2) the role of two geometric tasks, one driven by spontaneous behaviour (“social-cued memory task”) and the other by learning processes (“rewarded exit task”); 3) the involvement of extra-visual sensory channels in visual transparency conditions, and motion patterns. The present Thesis applied behavioural assessments and analyses to pursue a line of comparison, across species, methodologies, and sensory systems. As regards environmental geometry and landmarks in fish and tortoises (Chapter 2), the studies were carried out within several apparatuses, that is, a rectangular opaque arena or two different sized square opaque arenas or a transparent square arena, with conspicuous or local landmarks: Study 1, Conspicuous landmark (blue wall) in zebrafish; Study 2: Local landmarks (corner panels) in zebrafish; Study 3, Environmental geometry in tortoises; Study 4, Conspicuous landmark (blue wall) in tortoises. As regards spontaneous vs. acquired geometric spatial reorientation in fishes (Chapter 3), the studies were carried out within a rectangular or square transparent arena, with or without geometric cues or a 3D landmark: Study 5, Nonvisual environmental geometry in zebrafish, redtail splitfin fish, and goldfish; Study 6, Isolated environmental geometric cues in zebrafish; Study 7, 3D outside landmark (blue cylinder) in zebrafish. As regards extra-visual sensory systems and motion patterns in fish (Chapter 4), one study was carried out within a rectangular transparent arena: Study 8, Lateral line pharmacological ablation in zebrafish. In respect of comparisons among species, overall results suggested that zebrafish, redtail splitfin fish, and goldfish reoriented similarly through transparent surfaces, which defined a distinctive global shape, supporting spatial reorientation under undefined situations (e.g., seek out food within a visually lacking and unenriched environment) as a shared skill among teleosts, despite ecological specificities. Likewise, the Hermann tortoise reoriented within a geometric environment with precision to meet a survival need, suggesting that even non-nomadic species that hibernate for long can benefit from orientation by extended terrain surfaces. In respect of memory tests (“working” vs. “reference”, spontaneous vs. acquired), overall results indicated that the rewarded exit task designed to train fish and tortoise to reorient required learning processes allowing them to overcome natural predispositions to improve other related abilities, such as landmark-use. The dissociation between working and reference memory in spatial domain must be considered highly dependent on task’s demands where attentional factors determine short-term memories and motivational states long-term ones. In respect of sensory channels and motion patterns, overall results revealed that fish and tortoises used modalities driven by touch, in synch with sight, to determine geometric parameters during spatial reorientation. Therefore, a promising link between other vertebrates and humans takes place, in consideration of orientation mechanisms used to face situations of visual deprivation or impairments. The present Thesis may even contribute to a general understanding of reorientation behaviour in phylogenetically remote vertebrate species, thus supporting the widespread use of geometry-grounded tools in everyday activities. This also provides comparative support among species that inhabit on Earth and share cognitive adaptations to deal with similar requests.

This research examined the processes involved when one is acquiring spatial knowledge while traversing an environment, integrating that knowledge into mental representations, and subsequently relying on that knowledge to successfully perform wayfinding. Particularly, the conducted studies aimed to provide evidence reflecting on two ongoing debates: the distinctions between types of knowledge embedded in mental maps, and the unconfirmed sequential or simultaneous nature of the acquisition and integration of those types. The experiments reported in this manuscript addressed drawbacks in existing research by manipulating opportunities for the acquisition of point and route knowledge (two of the potentially distinct knowledge types), and by testing participants' capacity to integrate their acquired knowledge in the context of environmental affordances. Participants in the conducted studies underwent environmental training exposures targeted at providing a) primarily point knowledge or b) route knowledge acquisition, and they also completed a set of knowledge measures tapping point, route, and configuration knowledge. Finally, participants completed tests of wayfinding capacity to demonstrate their ability to rely on integrated mental maps for successful wayfinding. Results of the two conducted studies provided substantial evidence that there are distinct types of knowledge that may be acquired and quantifiably measured, and that spatial knowledge can be acquired in parallel, not necessarily in sequence, across knowledge types. Critically, some knowledge types may also develop in exclusion to others especially for individuals with particular spatial abilities and predispositions. Accordingly, it is likely that previous research indicating sequential spatial knowledge development may be reflecting differential acquisition as a combination of population capabilities and knowledge measurement research methodologies. Finally, the results demonstrate that individual differences, training modalities, and environment iv features have complex, interacting effects on spatial cognition and that no one factor predominantly determines individuals' ability to acquire, integrate, or employ spatial knowledge.

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The ability to remember spatial locations is critical to human functioning, both in an evolutionary and an everyday sense. And yet, spatial memories and judgments often show systematic errors. Explanations for such errors have ranged from assumptions that memories are nonmetric, to the use of imperfect inferences, to the optimal combination of multiple sources of information. More recently, bias has been explained through the Category Adjustment Model - a Bayesian model in which fine-grained and categorical information are optimally combined (Huttenlocher, Hedges, & Duncan, 1991). However, experiments testing this model have largely used locations contained in simple geometric shapes. Use of this paradigm raises the issue of whether the results generalize to location memory in the complex natural world, as it should if it is to provide an over-arching framework for thinking about spatial memory. Here, this issue is addressed using a novel extension of the location memory paradigm that allows for testing of location memory in an everyday, 3D environment. The results support two predictions of the Category Adjustment Model - that memory for locations is biased toward central values, and that the magnitude of error increases with the retention interval. Future directions for testing the model in an increasingly ecologically valid manner are discussed. / Psychology

Navigation proficiency - the ability to find and recall new and familiar locations - varies widely among individuals (e.g., Schinazi, Epstein, Nardi, Newcombe, & Shipley, 2013; Weisberg, Schinazi, Newcombe, Shipley, & Epstein, 2014). The cognitive processes that support effective navigation have been theoretically sketched out (e.g., Wolbers & Hegarty, 2010), but how do those processes contribute to aspects of and individual differences in navigation behavior? Using a virtual environment to assess navigation proficiency (Weisberg et al., 2014), we conducted two studies to investigate whether individual differences in navigating meaningfully relate to memory capacity (Study1) and navigation strategy (Study 2). Results from Study 1 suggest that working memory capacity may limit some participants' ability to build accurate cognitive maps. Using a virtual environment paradigm based on the rodent T-maze (Marchette, Bakker, & Shelton, 2011), Study 2 shows that good navigators do not prefer to use a place-based strategy over a response-based strategy, but there was an interaction between strategy selection and goals found. Good navigators who used a place-based strategy found more goals than good navigators who used a response-based strategy; the opposite was true for bad navigators. Emerging from this set of studies is a richer picture of how individual differences in cognitive traits (i.e., working memory capacity), and strategy choice relate to navigation proficiency. / Psychology

Walking is a natural part of our lives and is also becoming increasingly common in mixed reality. Wireless headsets and improved tracking systems allow us to easily navigate real and virtual environments by walking. In spite of the benefits, walking brings challenges to the design of new systems. In particular, designers must be aware of cognitive and motor requirements so that walking does not negatively impact the main task. Unfortunately, those demands are not yet fully understood. In this dissertation, we present new scientific evidence, interaction designs, and analysis of the role of walking in different mixed reality applications. We evaluated the difference in performance of users walking vs. manipulating a dataset during visual analysis. This is an important task, since virtual reality is increasingly being used as a way to make sense of progressively complex datasets. Our findings indicate that neither option is absolutely better: the optimal design choice should consider both user's experience with controllers and user's inherent spatial ability. Participants with reasonable game experience and low spatial ability performed better using the manipulation technique. However, we found that walking can still enable higher performance for participants with low spatial ability and without significant game experience. In augmented reality, specifying points in space is an essential step to create content that is registered with the world. However, this task can be challenging when information about the depth or geometry of the target is not available. We evaluated different augmented reality techniques for point marking that do not rely on any model of the environment. We found that triangulation by physically walking between points provides higher accuracy than purely perceptual methods. However, precision may be affected by head pointing tremors. To increase the precision, we designed a new technique that uses multiple samples to obtain a better estimate of the target position. This technique can also be used to mark points while walking. The effectiveness of this approach was demonstrated with a controlled augmented reality simulation and actual outdoor tests. Moving into the future, augmented reality will eventually replace our mobile devices as the main method of accessing information. Nonetheless, to achieve its full potential, augmented reality interfaces must support the fluid way we move in the world. We investigated the potential of adaptation in achieving this goal. We conceived and implemented an adaptive workspace system, based in the study of the design space and through user contextual studies. Our final design consists in a minimum set of techniques to support mobility and integration with the real world. We also identified a set of key interaction patterns and desirable properties of adaptation-based techniques, which can be used to guide the design of the next-generation walking-centered workspaces. / Ph. D. / Until recently, walking with virtual and augmented reality headsets was restricted by issues such as excessive weight, cables, tracking limitations, etc. As those limits go away, walking is becoming more common, making the user experience closer to the real world. If well explored, walking can also make some tasks easier and more efficient. Unfortunately, walking reduces our mental and motor performance and its consequences in interface design are not fully understood. In this dissertation, we present studies of the role of walking in three areas: scientific visualization in virtual reality, marking points in augmented reality, and accessing information in augmented reality. We show that although walking reduces our ability to perform those tasks, careful design can reduce its impact in a meaningful way.