This study examined individual differences in spatial memory performance in 12-month-old infants using brain electrical activity and walking experience. Greenough's experience-expectant and experience-dependent model of development was used to examine EEG power values among infants with different levels of walking experience (non-walkers, novice, experienced). In accordance with this model, a trend was shown for novice walkers to have higher EEG power values than both non-walkers and experienced walkers only in the central region. Walkers were also found to score higher on an object retrieval (OR) spatial memory task than non-walkers, with amount of walking experience being inconsequential. In addition, infants who scored higher on the OR spatial memory task showed a trend for higher EEG power values in medial frontal, central and parietal areas than infants scoring lower on the OR task. This was not the case for the manual search spatial memory task (AB). There was no interaction among spatial memory performance, walking experience and brain electrical activity. The utility of OR as a spatial memory task that requires the integration of relevant perceptual-motor integration is discussed. / Master of Science

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Humans have a strong natural ability to remember item locations. In graphical user interfaces, this ability is one of the primary mechanisms by which users become efficient. However, there are two ways in which modern applications often fail to exploit the potential of spatial memory. First, they overuse hierarchical structures such as cascading menus, which slows down interaction for expert users who already know item locations; and second, they move items around, most commonly in response to changing display geometry. The three goals of this thesis are therefore to (1) develop a better understanding of human spatial memory in the context of user interfaces; (2) design and validate efficient command-selection interfaces based on the strength of spatial memory; and (3) design and validate interface strategies that allow users to maintain spatial memory even when display geometry changes. Addressing goal (1), a comprehensive literature review of spatial memory for user interfaces is presented. The review covers underlying psychological models of spatial memory, the observable properties of spatial memory, and existing applications of spatial memory to human-computer interaction. In addition to informing the research in this thesis, the review is intended to provide a useful summary of the state of spatial memory research for scientists in HCI, as well as providing a set of design guidelines on spatial memory for practitioners. Addressing goal (2), this thesis presents the design and evaluation of two related user interface techniques, CommandMaps and StencilMaps. The CommandMap is a spatially stable interface with a flattened hierarchy, intended as a replacement for cascading menu systems. Theoretical performance predictions indicate that CommandMaps should be significantly faster than traditional user interfaces such as menus and the Microsoft Office Ribbon, and laboratory-based empirical studies of command selection confirm these predictions. These positive results motivated the design and implementation of two real-world CommandMap user interfaces based on Microsoft Word and Pinta (an open-source image editing application). Evaluation results confirmed that CommandMaps continue to demonstrate performance and subjective advantages in the context of actual tasks, including interleaved command selection, typing, and direct manipulation. Qualitative data gathered from interviews, questionnaires, and conversations provide substantial insight into users' reactions to CommandMaps, leading to a set of design recommendations regarding when and how they should be implemented in real applications. One design limitation identified during CommandMap evaluations was that novice users could be initially overwhelmed by the number of controls displayed at once. To address this concern, an extension to the CommandMap, called a StencilMap, was designed and evaluated. By using a stencil overlay to de-emphasise more advanced controls, the StencilMap directs users' visual search to a subset of controls they are most likely to need. Then, when novice users progress to the full interface, they can utilise their existing knowledge of command locations. An initial study shows that stencils are more effective at guiding visual search than ephemeral adaptation, another subset emphasis technique; however, users' spatial learning decreases as the amount of guidance increases. A second study compared StencilMaps to a palette-based subset interface, which displays the most likely commands in a ready-to-hand tool panel. Results show that StencilMaps enable stronger learning of the full UI compared to the palette approach. Addressing goal (3), this thesis presents an investigation of how interfaces can be adapted to changing interface constraints while still supporting the user's memory for item locations. A human factors study on spatially consistent transformations was conducted, with results showing that people's spatial memory is only minimally disrupted by geometric transformations (such as scaling, translation, or perspective distortion), as long as the set of items in a display is transformed as a whole. This idea is then applied to a file browser layout: by scaling the item grid when the parent window is resized, rather than reflowing items, memory for item locations can be maintained. A second study validates this idea, showing that a scaling interface outperforms both reflow and scrolling-based techniques for revisitation when windows are resized. In summary, the contributions of this thesis are: (1) an in-depth literature review of spatial memory in psychology and HCI, which is intended to inform designers and future researchers as well as the material in this thesis; (2) the design, implementation and evaluation of a new interface, the CommandMap, which shows that spatial stability and hierarchy flattening enable a high ceiling of expert performance; (3) the design of a stencil overlay technique to help novice users find commands, and an evaluation highlighting the key trade-off between helping users and allowing them to learn; and (4) empirical evidence showing that most types of whole-interface transformations have a small effect on spatial memory, and that correspondingly, scaling interfaces outperform reflowing interfaces under changing window constraints.

The goal of this thesis is to understand how children and adults scale distance. My preliminary work has shown that young children can accurately scale distances along a single dimension (i.e., length) even when the magnitude of the scale difference is very large. In these studies, 4- and 5-year-olds and adults first saw a location marked on a narrow mat placed on the floor of one testing space. They then reproduced that location on another narrow mat that was either the same length (i.e., the memory task) or a different length (i.e., the memory + scaling task) placed on the floor of an adjacent testing space. These experiments illustrated that both children and adults had more difficulty scaling up than scaling down (i.e., had more difficulty going from a small to a large mat than from a large to a small mat). In the present thesis, I used this difference between scaling up and scaling down as a tool to examine the processes underlying the ability to scale distance more generally. I predicted that the difficulty children and adults have scaling up can be attributed to mapping relative distances onto spaces that are too large to be viewed from a single vantage point. Experiment 1 demonstrated that although a visible boundary dividing a large space influenced how children and adults remember locations, scaling up was still more difficult than scaling down. Experiments 2 and 3 examined the influence of absolute size on mapping relative distance. When the absolute size of the test space was reduced, scaling up was no longer more difficult than scaling down. In contrast, when the absolute size was large, both scaling up and scaling down were more difficult, illustrating the importance of absolute size in using relative distance to scale. These findings suggest that when the absolute size of the space is large, children and adults have more difficulty using multiple edges of the space to accurately scale distance. More generally, these experiments underscore how the cognitive system and task structure interact to give rise to the ability to use relative distance to scale.

Recent research has revealed many similarities between episodic memory, scene construction, and imagination of the future. It has been suggested that scene construction is the common process underlying memory and imagination, but no study to date has directly compared all three abilities. The present study compared retrieval time, ratings of detail and vividness for episodic memories, remembered scenes and imagined future events cued by landmarks of high and low familiarity. Memories, scenes, and imagined episodes based on a more familiar landmark as a cue were more quickly retrieved, more detailed, and more vivid. This study was the first to demonstrate the effects of frequent encounters with a cue on memory, scene construction and imagination of the future. Additionally, consistent results across conditions, as well as stronger effects in the scene construction condition, provide further evidence of a possible interdependence of episodic memory, imagination of the future, and scene construction.

Recent research has revealed many similarities between episodic memory, scene construction, and imagination of the future. It has been suggested that scene construction is the common process underlying memory and imagination, but no study to date has directly compared all three abilities. The present study compared retrieval time, ratings of detail and vividness for episodic memories, remembered scenes and imagined future events cued by landmarks of high and low familiarity. Memories, scenes, and imagined episodes based on a more familiar landmark as a cue were more quickly retrieved, more detailed, and more vivid. This study was the first to demonstrate the effects of frequent encounters with a cue on memory, scene construction and imagination of the future. Additionally, consistent results across conditions, as well as stronger effects in the scene construction condition, provide further evidence of a possible interdependence of episodic memory, imagination of the future, and scene construction.

Kindling involves the progressive development of epileptiform activity that culminates in generalized seizures in response to repeated electrical stimulation of the brain. Kindling induces widespread changes in synaptic sensitivity and neuronal reactivity. These neuroplastic changes are evident in altered memory and behavior. This research was designed to further our understanding of kindling-induced deficits in spatial cognition. Two questions were examined: 1)does entorhinal cortex kindling disrupt spatial cognition; and 2)can bilateral bifocal kindling, of two brain regions known to participate in spatial cognition, produce larger cognitive deficits than unifocal kindling? This research attempted to confirm the spatial cognitive effects produced by unifocal dorsal hippocampal (dHPC) kindling, as a positive control. In contrast, the spatial cognitive effects produce by unifocal entorhinal cortex (EC) and bifocal kindling (i.e., EC kindling with subsequent contralateral dHPC kindling) are unknown and were examined here. Rats were subjected to unifocal EC kindling, unifocal dHPC kindling, or bifocal kindling. Rats exhibited fully generalized seizures prior to Morris water maze training from days 2 to 31. Visible platform trials were used to examine escape motivation and gross motor coordination, and all groups performed adequately. Consistent with previous research, dHPC kindling disrupted performance during acquisition trials; however, EC and bifocal kindling failed to disrupt acquisition. During retention trials, the bifocal kindling group displayed a disruption in performance; however, dHPC and lateral EC kindling failed to affect retention. The bifocal kindled group failed to display larger deficits than the unifocal kindled groups. These data suggest that the number of kindling stimulations given to a particular site may play a critical role in site-dependent disruption of memory.

Kindling involves the progressive development of epileptiform activity that culminates in generalized seizures in response to repeated electrical stimulation of the brain. Kindling induces widespread changes in synaptic sensitivity and neuronal reactivity. These neuroplastic changes are evident in altered memory and behavior. This research was designed to further our understanding of kindling-induced deficits in spatial cognition. Two questions were examined: 1)does entorhinal cortex kindling disrupt spatial cognition; and 2)can bilateral bifocal kindling, of two brain regions known to participate in spatial cognition, produce larger cognitive deficits than unifocal kindling? This research attempted to confirm the spatial cognitive effects produced by unifocal dorsal hippocampal (dHPC) kindling, as a positive control. In contrast, the spatial cognitive effects produce by unifocal entorhinal cortex (EC) and bifocal kindling (i.e., EC kindling with subsequent contralateral dHPC kindling) are unknown and were examined here. Rats were subjected to unifocal EC kindling, unifocal dHPC kindling, or bifocal kindling. Rats exhibited fully generalized seizures prior to Morris water maze training from days 2 to 31. Visible platform trials were used to examine escape motivation and gross motor coordination, and all groups performed adequately. Consistent with previous research, dHPC kindling disrupted performance during acquisition trials; however, EC and bifocal kindling failed to disrupt acquisition. During retention trials, the bifocal kindling group displayed a disruption in performance; however, dHPC and lateral EC kindling failed to affect retention. The bifocal kindled group failed to display larger deficits than the unifocal kindled groups. These data suggest that the number of kindling stimulations given to a particular site may play a critical role in site-dependent disruption of memory.

While episodic and spatial memory both depend on the hippocampus, opposite gender differences in these functions suggest they are partly separate, with different neural underpinnings. The anterior and posterior hippocampus differ  in structure and whole-brain connectivity, and studies point to the posterior hippocampus being more involved in spatial memory while the anterior hippocampus’ role in episodic memory is less clear. This thesis aims to explore the role of the anterior and posterior hippocampus, and associated brain regions, in episodic and spatial memory. Paper I studied gender differences in hippocampal activation underlying differences in spatial memory performance. Better performance in men was accompanied by greater right-lateralization of hippocampal activation compared to women. Paper II investigated regions of gray matter that covaried in volume with the anterior and posterior hippocampus, and whether these covariance patterns depended on gender and were related to behavior. The anterior and posterior hippocampus showed different patterns of covariance, with the anterior hippocampus covariance pattern observed in women and the posterior hippocampus covariance pattern primarily in men. Paper III considered whether the location of hippocampal recruitment in episodic memory depends on memory content. Verbal stimuli were associated with more anterior, and left-lateralized, encoding activations than pictorial stimuli, which in turn were associated with more posterior and bilateral encoding activations. This was not observed during retrieval. Paper IV investigated whether resting-state connectivity associated with the anterior and posterior hippocampus predicts episodic and spatial memory performance, respectively. Resting-state connectivity associated with the anterior, not posterior, hippocampus predicted episodic memory performance, while resting-state connectivity associated with the posterior, not anterior, hippocampus predicted spatial memory performance. This thesis lends further support to differences in function and structure between the anterior and posterior hippocampus suggesting that these two sub–segments play different roles in episodic and spatial memory. Further, it suggests that gender differences in anterior and posterior hippocampus function underlies gender differences in episodic and spatial memory, respectively. Considering the anterior and posterior hippocampus, as well as men and women, separately, is hence important when studying the effect of age and pathology on the hippocampus and associated memory functions.

Thesis (Ph. D.)--Miami University, Dept. of Psychology, 2009. / Title from second page of PDF document. Includes bibliographical references (p. 53-59).