This investigation examined whether children can code the relative proximity of two objects to a landmark and whether they use verbal or nonverbal strategies to remember a target location. Two- to 2.5-year-olds completed a memory task where they watched an experimenter hide two different toys in two identical containers placed 2 and 12 inches from a landmark. The experimenter either used neutral language (e.g., “here”; Experiment 1) or spatial labels (e.g., “close/far”; Experiment 2) to describe objects’ hiding locations. After hiding, children were carried outside the enclosure to a new viewpoint during a 10-second delay and then looked for a target toy. Experiment 2 also included language measures: parent reports of children’s general and relational vocabularies and performance on a language task, which measured children’s understanding of spatial (close/far) and color (red/blue) terms. We found that children successfully coded relative to proximity to a landmark in the memory task. However, hearing spatial labels during hiding in Experiment 2 did not improve performance relative to Experiment 1, and children’s spatial term comprehension in the language task did not predict memory task performance. We also found that children’s productive relational vocabulary predicted memory task performance; however, children’s color term comprehension in the language task was the strongest overall predictor of memory task performance. Collectively, these results suggest that children initially rely on a nonverbal strategy when coding relative proximity to a landmark in a memory task and that children who are better at forming abstract categories may code relative proximity more successfully.

The purpose of this thesis was to determine whether asymmetry in metric and topological spatial judgments could be attributed to the spatial frequency of the stimulus or the size of the attended receptive field. A left hemisphere advantage has been found for topological judgments and a right hemisphere advantage for metric judgments. This asymmetry has been attributed to asymmetrical processing of input conditions, namely size of attended receptive field (called the attentional bin) and spatial frequency of the stimulus. The larger a stimulus, the higher the proportion of low spatial frequencies, so large stimuli are thought to facilitate the extraction of lower spatial frequencies while small stimuli are thought to facilitate the extraction of higher spatial frequencies. A left hemisphere advantage has been reported for high spatial frequencies and small attentional bins and a right hemisphere advantage has been reported for low spatial frequencies and large attentional bins. A method for pitting asymmetrically distributed input conditions against each other using asymmetrically distributed tasks was developed. Three studies were conducted. In the first study, a lack of hemisphere effects suggested bilateral processing of the stimuli. Using an eye tracker, participants were easily able to saccade to the stimulus as was shown in Experiment 2. In Experiment 3, effective exposure duration was reduced so that unilateral viewing was ensured. Under these conditions, bin size and spatial frequency were not dissociable due to a lack of hemisphere effects for spatial frequency and because of task dependency for bin size and spatial frequency processing. Although the assumptions of the double double dissociation were not met, asymmetry in spatial judgments under conditions comparable to those used by Kosslyn et al.(1989) was attributable to a right hemisphere advantage for processing through small attentional bins.

The purpose of this thesis was to determine whether asymmetry in metric and topological spatial judgments could be attributed to the spatial frequency of the stimulus or the size of the attended receptive field. A left hemisphere advantage has been found for topological judgments and a right hemisphere advantage for metric judgments. This asymmetry has been attributed to asymmetrical processing of input conditions, namely size of attended receptive field (called the attentional bin) and spatial frequency of the stimulus. The larger a stimulus, the higher the proportion of low spatial frequencies, so large stimuli are thought to facilitate the extraction of lower spatial frequencies while small stimuli are thought to facilitate the extraction of higher spatial frequencies. A left hemisphere advantage has been reported for high spatial frequencies and small attentional bins and a right hemisphere advantage has been reported for low spatial frequencies and large attentional bins. A method for pitting asymmetrically distributed input conditions against each other using asymmetrically distributed tasks was developed. Three studies were conducted. In the first study, a lack of hemisphere effects suggested bilateral processing of the stimuli. Using an eye tracker, participants were easily able to saccade to the stimulus as was shown in Experiment 2. In Experiment 3, effective exposure duration was reduced so that unilateral viewing was ensured. Under these conditions, bin size and spatial frequency were not dissociable due to a lack of hemisphere effects for spatial frequency and because of task dependency for bin size and spatial frequency processing. Although the assumptions of the double double dissociation were not met, asymmetry in spatial judgments under conditions comparable to those used by Kosslyn et al.(1989) was attributable to a right hemisphere advantage for processing through small attentional bins.

Thesis (M.S.) in Spatial Information Science and Engineering--University of Maine, 2001. / Includes vita. Bibliography: leaves 74-79.

An increasing amount of freely available Geographic Information System (GIS) data on the Internet has stimulated recent research into Spatial Information Retrieval (SIR). Typically, SIR looks at the problem of retrieving spatial data on a dataset by dataset basis. However in practice, GIS datasets are generally not analysed in isolation. More often than not multiple datasets are required to create a map for a particular analysis task. To do this using the current SIR techniques, each dataset is retrieved one by one using traditional retrieval methods and manually added to the map. To automate map creation the traditional SIR paradigm of matching a query to a single dataset type must be extended to include discovering relationships between different dataset types. This thesis presents a Bayesian inference retrieval framework that will incorporate expert knowledge in order to retrieve all relevant datasets and automatically create a map given an initial user query. The framework consists of a Bayesian network that utilises causal relationships between GIS datasets. A series of Bayesian learning algorithms are presented that automatically discover these causal linkages from historic expert knowledge about GIS datasets. This new retrieval model improves support for complex and vague queries through the discovered dataset relationships. In addition, the framework will learn which datasets are best suited for particular query input through feedback supplied by the user. This thesis evaluates the new Bayesian Framework for SIR. This was achieved by utilising a test set of queries and responses and measuring the performance of the respective new algorithms against conventional algorithms. This contribution will increase the performance and efficiency of knowledge extraction from GIS by allowing users to focus on interpreting data, instead of focusing on finding which data is relevant to their analysis. In addition, they will allow GIS to reach non-technical people.

The process of decision making is best undertaken with the consideration of as much information as possible. One way to maximise the amount of information that is being used in the process is to use metadata engines. Metadata engines can be used to create virtual databases which are a collection of individual datasets located over a network. Virtual databases allow decisions to be made using data from many different data bases at many different locations on a network. They shield the user from this fact. From the users point of view they are only using data from the one location. This thesis investigates some of the concepts behind metadata engines for Internet based Spatial Data Infrastructures. The thesis has a particular emphasis on how metadata engines can be used to create virtual databases that could be of use in the planning and decision making processes. The thesis also investigates some current spatial data technologies such as SDIs, data warehouses, data marts and clearing houses, their interoperability and their relationship to metadata engines. It also explores some of the more recent spatial data applications that have been developed in the context of metadata engines and Spatial Data Infrastructures.

This article summarizes the ideas behind a few programs we developed for spatial data analysis in EViews and MATLAB. They allow the user to check for spatial autocorrelation using Moran's I and provide a spatial filtering procedure based on the Gi statistic by Getis and Ord (1992). We have also implemented graphical tools like Moran Scatterplots for the detection of outliers or local spatial clusters.

This thesis encompasses five chapters. Chapter 1 details the background literature for how the inhibition of return effect manifests in 3D environments. Additional summary is provided about how positioning cues and targets within the boundary of the same objects affects the spread of IOR when compared to when attention is cued in empty space. Finally, the literature review also provides a background for whether the IOR effect is affected by a viewer-centered or world-centered frame of reference. Chapters 2-4 are empirical chapters. Chapter 2 observes a depth-specific IOR effect in a 3D composed of pictorial depth cues. Chapter 3 suggests that this depth-specificity can only occur when cues and targets are positioned in different objects rather than when positioned within a single object. Chapter 4 investigates how the distances between viewer and cue, viewer and target, and cue and target affect the magnitude of IOR, suggesting that the world-centered reference frame influences IOR. Chapter 5 serves as a general discussion and conclusion chapter, discussing the findings and implications of each empirical chapter. / The distribution of human attention in space can be modulated by spatial and temporal factors. This dissertation studied inhibition of return (IOR), a robust behavioural effect obtained through a spatial cueing paradigm where observers exhibit slower detection times to a target appearing over 300 ms after a cue in a previously cued location. Most research has studied the IOR effect in two-dimensional space; thus, it remains unclear whether, in three-dimensional space (3D) space, slower reaction times occur due to a target appearing in the same world location (defined in 3D coordinates) or in the same retinal location as the cue (i.e., anywhere along an observer’s line of sight to the cue). My thesis examines IOR in a computer-simulated 3D environment, with the location of the cue and target residing in the same versus different depth/distance position either within the same or different object and either relative to the observer or to the world environment. Following a general literature review (Chapter 1), the first empirical chapter (Chapter 2) demonstrates that IOR is depth-specific when the direction of depth switch between cue to target occurs from far-to-near space, suggesting a behavioural advantage for near space in the human attention system. Chapter 3 shows that this depth-specificity and depth-asymmetry of IOR is maintained only when cues and targets are not part of the same object; object membership can therefore override the depth-specific property of IOR in 3D scenes. Chapter 4 introduces motion of the viewpoint, showing that IOR is depth-specific when the cue and target appear in different depth locations in the world environment even when located at the same relative distance from the observer’s viewpoint. Thus, IOR could be the result of an inhibitory tag placed at a location relative to the environment rather than at a location relative to the viewpoint. / Dissertation / Doctor of Science (PhD) / Human attention can be distributed over space and affected by external events. Prior research using 2D environments has shown that some time after the first stimulus (a cue), the reaction time to a subsequent stimulus (a target) appearing in the same location is typically slower compared to when this target appears elsewhere. Thus, attention likely moves away from a previously observed to more novel location of interest. I examined, in a 3D environment, whether this “location” of reduced attention resides in the same 3D location or retinal location as that of the cue. I also assessed the impact on reaction time for when the cue and target belong to the same or different object and when their locations differ in reference to the observer or world environment. My research suggests that humans maintain a higher level of attention for nearer space when the cue previously appears at a farther location.

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