Issued also as the authors' Thesis--Yale.

Thesis (M.A.)--Carleton University, 2001. / Includes bibliographical references (p. 90-96). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Chicago, Committee on Human Development, Dept. of Psychology, Aug. 2002. / Includes bibliographical references (p. 113-126). Also available on the Internet.

Issued also as the authors' Thesis--Yale.

No description available.

Dopamine and 3',5'-cyclic adenosine monophosphate-regulated neuronal phosphoprotein (DARPP-32) is a critical mediator of neuroplasticity in striatal medium spiny neurons (MSNs). The work presented in this thesis used a global gene knockout (KO) construct to investigate the role of DARPP-32 in reward-based learning and performance. Global deletion of the DARPP-32 gene disturbed performance during the intertemporal (delay) discounting procedure. DARPP-32 KO mice were less sensitive than their wildtype (WT) littermates during long delays to reinforcement. In comparison to WT mice, DARPP-32 KO mice also developed a risk-sensitive pattern of choices during a probability discounting task. Unlike the effects of DARPP-32 deletion on reinforcement along dimensions of time and risk, DARPP-32 knockout did not affect the degree of effort that subjects were willing to invest during food-reinforced progressive ratio testing. DARPP-32 KO mice also failed to exhibit Pavlovian-to-instrumental transfer and this impairment could not be rescued by administering methylphenidate prior to test. Finally, DARPP-32 KO mice were indistinguishable from WT mice during an amphetamine psychomotor sensitisation study. Overall, the data in this thesis suggest DARPP-32 is involved in adaptive reward-based learning and performance.

The purpose of this library research thesis is to review the "longitudinal study" in terms of problems and present use. A preliminary search of the literature on longitudinal method revealed problems centering around two areas: (1) definition of "longitudinal study" and (2) practical problems of method itself. The purpose of this thesis then is to explore through a search of books and journals the following questions: 1. How can “longitudinal study” be defined? 2. What problems are inherent in the study of the same individuals over time and how can these problems be solved? A third question which emerges from these two is: 3. How is “longitudinal study” being used today? This thesis differentiates traditional longitudinal study from other methods of study: the cross-sectional study, the time-lag study, the experimental study, the retrospective study, and the study from records. Each of these methods of study is reviewed according to its unique problems and best uses and compared with the longitudinal study. Finally, the traditional longitudinal study is defined as the study: (1) of individual change under natural conditions not controlled by the experimenter, (2) which proceeds over time from the present to the future by measuring the same individuals repeatedly, and (3) which retains individuality of data in analyses. Some problem areas of longitudinal study are delineated which are either unique to this method or especially difficult. The following problems related to planning the study are reviewed: definition of study objectives, selection of method of study, statistical methods, cost, post hoc analysis and replication of the study, time factor in longitudinal study, and the problem of allowing variables to operate freely. Cultural shift and attrition are especially emphasized. The dilemma is examined which is posed by sample selection with its related problems of randomization and generalizability of the study, together with the problems of repeated measurements and selection of control groups. These problems are illustrated with studies from the literature. Not only are these problems delineated cut considerable evidence is shown that we have already started to accumulate data that will permit their solution. This paper presents a number of studies which have considered these problems separately or as a side issue of a study on some other topic. Some recommendations for further research in problem areas are suggested. At the same time that this thesis notes differentiation of the longitudinal study from other studies, it also notes integration of results of longitudinal studies with results of other studies. The tenet adopted here is: scientific knowledge is cumulative and not dependent on one crucial experiment. Trends in recent longitudinal studies are found to be toward more strict observance of scientific protocols and toward limitation of time and objectives of the study. When objectives of the study are well defined and time is limited to only enough for specified change to take place, many of the problems of longitudinal study are reduced to manageable proportions. Although modern studies are of improved quality, longitudinal method is not being sufficiently used today to supply the demand for this type of data. Longitudinal study is necessary to answer some of the questions in developmental psychology. We have no alternative but to continue to develop this important research tool.

Scholars in diverse disciplines are currently engaged in debates concerning the causes and consequences of human social interaction in areas including personality development, interpersonal characteristics, social attachments and support, family life, religious involvement, civic engagement, socioeconomic attainment, and health and wellbeing, among others. Unfortunately, researchers in these areas are compartmentalized into two, largely isolated, camps: (1) social scientists who base their research on the assumption that social outcomes are primarily, if not exclusively, the products of social-environmental influences; and (2) biologists, geneticists, psychiatrists, and some psychologists, all of whom assume that genetic factors are important as well. The purpose of this dissertation, therefore, is to begin integrating sociological and biomedical research on social life. To facilitate this task, four specific research questions are addressed: Do genetic and environmental factors both influence social life, and if so, what is the relative contribution of each? Why and how do genetic factors influence social life, and what are the pathways by which they operate? Are genetic and environmental influences on social life correlated (i.e., non-additive), and do genetic factors bias social scientific studies that do not take them into consideration? Do genetic and environmental factors interact to produce social outcomes? To answer these questions, twin sibling data from the National Survey of Midlife Development in the United States (MIDUS) is analyzed. In response to the first question, results reveal that both genetic and environmental factors are indeed important predictors of individual-level variation on several different aspects of social life, including religious involvement, civic engagement, personality and interpersonal characteristics, family relations, socioeconomic status, community attachment, neighborhood quality, and psychological distress. Further, genetic effects on several of these outcomes (e.g., civic engagement, psychological distress) are mediated by personality, interpersonal characteristics, and social relationships, which provides insight into the second and third research questions. With respect to the final question, the findings presented here suggest that genetic and environmental influences on at least one social outcome--health and well-being--function in both a correlated and interactive manner. Overall, the theoretical and empirical research provided in this dissertation highlights a growing need for research that integrates sociological and biological approaches to the study of social life. / text

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

No description available.