published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / Educational Psychology / Master / Master of Social Sciences

published_or_final_version / Clinical Psychology / Master / Master of Social Sciences

published_or_final_version / Psychology / Doctoral / Doctor of Philosophy

The fractionation of zircons by sedimentary processes into continental margin sandstone deposits results in a biased preservation of pre-existing continental crust in the form of zircon in those sequences. This provides a unique opportunity to distinguish between the contrasting theories of episodic growth versus constant volume of continental crust over geologic time through Hf isotope ratios of detrital zircons. ¹⁷⁶Hf/¹⁷⁷Hf ratios were determined for detrital zircon fractions from 2.6-3.0 Ga old sedimentary sequences from the Canadian Shield, North Atlantic, Wyoming, and Kaapvaal Cratons. Hf T(CHUR) ages are less than 3.0 Ga and ε(Hf) values are positive or slightly negative at the time of deposition for most of the Malene, Canadian Shield, Wyoming and upper portions of the Kaapvaal sediments. Notable exceptions are basal samples of the Pongola (3.32 Ga), Dominion (3.11 Ga) and Witwatersrand (3.13 Ga), an arkose from Michigan (3.20 Ga) and one Malene sample (2.97 Ga), all of which either unconformably overlie or are closely associated with pre-3.0 Ga crust. Nd data for shales from the same sequences in the Canadian Shield and Kaapvaal sequences mimic the Hf results. The late Archean sequences appear to be dominated by zircon populations of late Archean age. Hf model ages, from pre-3.0 Ga strata (Upernavik of Labrador and quartzites from Montana), range from 3.1 to 3.6 Ga and are broadly consistent with ages of coexisting volcanics or intrusives, suggesting little inheritance of significantly older material. 2.0-2.5 Ga old quartzites from the Canadian Shield, Wyoming and South Africa have 2.58 to 2.84 Ga model Hf ages indicative of a large expanse of late Archean crust exposed at the time of deposition. The data strongly suggest inheritance of pre-3.0 Ga zircons only in areas where pre-3.0 Ga old crust exists today, and imply that the quantity of continental crust prior to 3.0 Ga ago was not much greater in extent than the pre-3.0 Ga crust exposed today. Small amounts of continental crust prior to 3.0 Ga ago and rapid addition of continental crust between 2.5 and 3.0 Ga ago are consistent with the episodic growth theory of crustal evolution.

Individual differences in problem-solving have been studied from both information-processing and developmental psychology perspectives. The purpose of the present research was to use an information-processing approach to investigate the effects of both age and intelligence on the performances by young persons on experimental tasks which required systematic application of appropriate solution rules. Eighty 10- and 15-year-old subjects were assigned to one of eight groups on the bases of their ages, sex, and intelligence levels. The testing condition was the same for all groups. Stimulus materials consisted of a two-pan balance and a variety of different-density cubes. Subjects' responses to the materials were their predictions of equilibrium or imbalance. Correct solutions required understanding of the physical science concepts of volume and density, and the mathematics concept of proportionality. From analysis of variance performed on the data, it was found that males and females did not differ in their abilities to problem-solve. The highly-intelligent subjects had a greater frequency of correct responses in both age groups, and the older subjects outperformed younger subjects. The equilibrium problems presented in the study were of six separate types, and the interaction effects in the data revealed that the six types were of varying levels of difficulty. It was in the analyses of the subjects' patterns of responses to the several types that the most theoretically interesting results appeared. Examination of the response patterns led to assignment of the respondents to categories of probable rule-usage. The less sophisticated problem-solvers did not take density into account and consistently relied on their knowledge of the volume concept in making their decisions. Solvers functioning at higher rule-levels were able to consider density as well before making their predictions, although a substantial number failed to use cues present in the experiment to reckon the respective densities correctly. Fully-functional problem-solvers gave responses which showed their mastery of the mathematics of proportionality. Twenty-four subjects participated in a second experiment which was a short demonstration-oriented training study providing feedback, although the algorithm for correct problem solution was not directly taught. Results were discussed in terms of the efficacy of the rule-usage model.

For gender-related information, previous studies have shown that children of preschool age are more likely to remember schema-consistent information over schema-inconsistent information. In this study, an attempt was made to boost children's recognition for inconsistent information. In order to do this, children were presented with pictures of both gender-consistent and inconsistent content. Group one was presented with the pictures and an accompanying label. For group two, children were given a label and asked to describe only the pictures where an actor was performing counter-schematic behavior. The postulated mechanism responsible for the expected change in memory for group two involved an augmentation of the schematic structure. The children's description would encourage schematic growth, and the memory benefits that are derived from schematic organization would have been the result. Group three was added to test for the memory changes that may occur when describing consistent information as well. These children were asked to describe both consistent and inconsistent information. Overall results indicated that for children not describing the stimuli, previous research went unsupported and children did not have a better memory for either type of information. Children in group two also did not have a memory preference for either type of information. Children in the third group which described both inconsistent and consistent information, though, did have a memory preference for consistent information. The results are described in terms of social change and schematic complexity, and their effects on memory. / Graduation date: 1998

Thesis (Ph. D.)--University of North Carolina at Greensboro, 2006. / Title from PDF title page screen. Advisor: Terri Shelton; submitted to the Dept. of Psychology. Includes bibliographical references (p. 69-83).

Thesis (Ph.D.)--York University, 2004. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 104-113). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99239

Thesis (M.A.)--York University, 2004. Graduate Programme in Film and Video. / Typescript. Includes bibliographical references (leaves 33-34). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL:http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss&rft%5Fval%5Ffmt=info:ofi/fmt:kev:mtx:dissertation&rft%5Fdat=xri:pqdiss:MQ99298