This dissertation consists of three research papers on Preference models of decision making, all of which adopt an axiomatic approach in which preference conditions are studied so that the models in this dissertation can be verified by checking their conditions at the behavioral level. The first paper “Utility Functions Representing Preference over Interdependent Attributes” studies the problem of how to assess a two attribute utility function when the attributes are interdependent. We consider a situation where the risk aversion on one attribute could be influenced by the level of the other attribute in a two attribute decision making problem. In this case, the multilinear utility model—and its special cases the additive and multiplicative forms—cannot be applied to assess a subject’s preference because utility independence does not hold. We propose a family of preference conditions called nth degree discrete distribution independence that can accommodate a variety of dependencies among two attributes. The special case of second degree discrete distribution independence is equivalent to the utility independence condition. Third degree discrete distribution independence leads to a decomposition formula that contains many other decomposition formulas in the existing literature as special cases. As the decompositions proposed in this research is more general than many existing ones, the study provides a model of preference that has potential to be used for assessing utility functions more accurately and with relatively little additional effort. The second paper “On the Axiomatization of the Satiation and Habit Formation Utility Models” studies the axiomatic foundations of the discounted utility model that incorporates both satiation and habit formation in temporal decision. We propose a preference condition called shifted difference independence to axiomatize a general habit formation and satiation model (GHS). This model allows for a general habit formation and satiation function that contains many functional forms in the literature as special cases. Since the GHS model can be reduced to either a general satiation model (GSa) or a general habit formation model (GHa), our theory also provides approaches to axiomatize both the GSa model and the GHa model. Furthermore, by adding extra preference conditions into our axiomatization framework, we obtain a GHS model with a linear habit formation function and a recursively defined linear satiation function. In the third paper “Hope, Dread, Disappointment, and Elation from Anticipation in Decision Making”, we propose a model to incorporate both anticipation and disappointment into decision making, where we define hope as anticipating a gain and dread as anticipating a loss. In this model, the anticipation for a lottery is a subjectively chosen outcome for a lottery that influences the decision maker’s reference point. The decision maker experiences elation or disappointment when she compares the received outcome with the anticipated outcome. This model captures the trade-off between a utility gain from higher anticipation and a utility loss from higher disappointment. We show that our model contains some existing decision models as its special cases, including disappointment models. We also use our model to explore how a person’s attitude toward the future, either optimistic or pessimistic, could mediate the wealth effect on her risk attitude. Finally, we show that our model can be applied to explain the coexistence of a demand for gambling and insurance and provides unique insights into portfolio choice and advertising decision problems. / text

This dissertation examines what motivates individuals to prefer certain types of product attributes over others. It is proposed that consumer preference regarding product attributes is fundamentally connected to an individual’s future orientation, i.e., how a person perceives, thinks about, and copes with time left in life. Specifically, it is posited that future orientations play key roles in shaping a person’s criteria in product evaluation. Thus, this dissertation seeks to integrate the study of future orientation with research on socio-emotional selectivity influences on consumption. Building on past research, this study proposes a conceptual model including four constructs: future orientations, chronological age, product evaluation, and preferences. An experimental study was used to investigate the research objectives and calibrate and validate the model. The experiment examines the moderating effect of future orientations and chronological age on consumer preference for hedonic vs. utilitarian attributes. The subjects were randomly assigned to one of two future orientations (expansive and limited) and one of two attributes contexts (hedonic and utilitarian). The sample for this study was drawn from consumers in Metropolitan Atlanta, Georgia. The research results will lead to an improved understanding of how preference varies from individual to individual and changes over time. In particular the research will provide insights about the impact of an individual’s future orientation on product attitude. The findings will advance current theory in both the new product evaluation and preference literature and have implications for the practice of marketing at levels of marketing strategy, product development, integrated marketing communications and loyalty programs.

Maternal consumption of alcohol during pregnancy is associated with alterations in fetal development that negatively impact the offspring causing neurochemical and neurobehavioural dysfunction termed fetal alcohol spectrum disorders; the most severe outcome is fetal alcohol syndrome. Changes in maternal and fetal hypothalamic-pituitary-adrenal (HPA) axis activation, induction of cytochrome P450 2E1 (CYP2E1) enzyme activity and alterations in micronutrient status, including folate, following chronic ethanol exposure (CEE) are key contributors to the neuroendocrine and neurobehavioural effects observed in offspring. This study tested the following hypotheses: Maternal consumption of ethanol throughout pregnancy can: alter maternal and fetal HPA axis function and induce CYP2E1 enzyme activity in the third-trimester-equivalent; decrease folate status in the maternal-fetal unit, which can be mitigated by folic acid supplementation; and cause neurobehavioural deficits in offspring at low-moderate dose of maternal ethanol consumption. These hypotheses were tested in the guinea pig, a well established model of ethanol neurobehavioural teratogenicity. CEE had no effect on maternal HPA axis function at any gestational day (GD). Fetal cortisol was unaffected by CEE, but did increase with gestational age in both CEE and control. CEE increased maternal and GD 65 fetal liver CYP2E1 enzyme activity. Maternal supplementation with folic acid did not mitigate CEE fetal growth restriction, but did increase maternal red blood cell (RBC) folate at term. At term, maternal supplementation prevented the CEE-induced decrease in fetal liver folate, did not affect fetal RBC folate, and did not mitigate the nutritional-deficit-induced decrease in fetal hippocampal folate. Maternal consumption of 5% (v/v) ethanol decreased offspring birth weight, increased spontaneous locomotor activity, increased preference for ethanol, and delayed learning on day two of Morris water maze testing in young adult offspring. These data indicate that, in the guinea pig: there is a threshold blood ethanol concentration for HPA axis activation; CEE can induce CYP2E1 in the GD 65 fetus; folic acid supplementation is not protective in this model of CEE; and low-moderate CEE can cause neurobehavioural perturbations in offspring. / Thesis (Ph.D, Pharmacology & Toxicology) -- Queen's University, 2012-05-31 14:38:44.391

When assessing preferences of individuals with developmental disabilities, choices can be described vocally or presented using objects or pictures in preference assessments. For individuals who are unable to perform auditory-visual discriminations and visual identity matching, objects instead of pictures or vocalizations need to be used for preference assessments to be effective. Considering the practical advantages of using pictures over objects, recent research has begun to focus on identifying and teaching skills needed for picture preference assessments. Although object-to-picture, picture-to-object, and generalized matching have been implicated as possible skills needed for picture preference assessments, further systematic studies are needed. The present study examined the relation between preference assessments (object vs. picture groups) and 5 discrimination skills. Based on direct paired-stimulus preference assessments completed at the beginning of the study, participants who could indicate their preferences with objects, but not with picture or vocal presentation, were assigned to the Object Group (n = 11); and participants who could indicate their preferences with both objects and pictures, but not vocal presentation, were assigned to the Picture Group (n = 9). The 5 discrimination tasks included: (a) object-picture matching and (b) its symmetry, picture-object matching; (c) generalized object-picture matching and (d) its symmetry, generalized picture-object matching; and (e) generalized identity picture-picture matching. All task stimuli were parts from everyday objects. Independent sample t-tests with Bonferroni correction showed that the percentages of correct responses were significantly higher in the Picture Group than in the Object Group on 4 of the 5 tasks (p < .01). Individual data showed that 8 of the 9 Picture Group participants met the pass criterion (80% or higher correct responses) on at least 1 discrimination task, with 6 participants passing 2 or more tasks. In contrast, only 1 of the 11 Object Group participants met the pass criterion on 1 discrimination task. The findings suggest that the effectiveness of picture preference assessments is not dependent on one specific discrimination, but possibly the ability to perform generalized matching.

Past research has shown that preference for a stimulus is correlated positively with reinforcer efficacy – more preferred stimuli tend to be more potent reinforcers. Researchers have recently examined the use of progressive ratio (PR) reinforcement schedules to evaluate preference. However, research on the concordance between preference and performance under a progressive ratio schedule is limited. Therefore, two experiments were conducted to extend this research. In Experiment 1 I compared the relative reinforcing efficacy of six stimuli obtained under a PR schedule to the mean preference hierarchy obtained through paired-stimulus preference assessments conducted before and after PR reinforcement sessions. In Experiment 2 I evaluated the PR schedule for quantifying the reinforcing value of three stimuli from Experiment 1 (i.e., one high, one medium, and one low preference stimulus). The results of Experiment 1 indicated that items that yielded higher breaking points and responses per minute were also more preferred. However, concordance between percent preference and breaking points and response rates for less preferred items was more variable. The results of Experiment 2 showed that high preference stimuli increased responding over baseline for all participants. However, low preference reinforcers also increased responding over baseline for some participants.

Metal oxide materials are a broad class of materials found in many current technologies due to their interesting properties such as magnetism and ferroelectricity. Material properties can be tuned and heavily influenced by disorder at the atomic level, as has been shown in the ferrimagnetic and ferroelectric Al2-x-yGaxFeyO3 materials, which adopt the non-centrosymmetric, orthorhombic GaFeO3 crystal structure-type (Pna21). The significant cation disorder and non centrosymmetric nature of the crystal structure underlie the multiferroic properties in these materials and make them one of the few chemical systems to possess multiferroic ordering near room temperature. Unfortunately, while cation site disorder is responsible for the multiferroic properties observed in these compounds, their complex crystal structure has led to inconsistent reports in the ternary Al2-xFexO3 and Ga2-xFexO3 compounds. X-ray absorption near-edge spectroscopy (XANES) is an element specific technique, which can be used to examine cation site disorder as a function of changes in the average coordination environment around the metal, providing a means of studying these complex materials. In this thesis, XANES was used to investigate factors affecting cation site disorder in a series of Al1-xGaxFeO3 materials (0 ≤ x ≤ 1) adopting the GaFeO3 crystal structure-type. The GaFeO3 crystal structure has four cation sites, of which, the distorted octahedral Fe1 and Fe2 sites are primarily occupied by Fe3+, and the less distorted tetrahedral A1 and octahedral A2 sites are primarily occupied by Al3+ or Ga3+. These materials were initially synthesized using a high temperature ceramic method, and it was found that with increasing Ga3+ content (x) these materials show a decrease in the amount of cation site disorder between the tetrahedral site and the three octahedral sites. This decrease is attributed to the tetrahedral site preference of Ga3+, which inhibits cation site disorder at the A1 site, as opposed to the octahedral site preference observed for Al3+. Additionally, Fe3+ was found to predominantly occupy the three octahedral sites over the tetrahedral site in these materials, likely because of its large ionic size and the strong magnetic coupling between those three sites. The quaternary Al1-xGaxFeO3 materials (0 ≤ x ≤ 1) were synthesized again via two other techniques: a citrate sol-gel method and a co-precipitation method. The oxide network binding the binary metal oxide precursors limits ion mobility in the high temperature ceramic method. The citrate sol-gel and co-precipitation methods were used to generate mixed-metal precursors with a more homogeneous distribution of the metal cations than the binary metal oxide precursors commonly used by the high temperature ceramic method. Mixed-metal precursors reduce the distance the ions have to diffuse, while the nature of the amorphous matrix was found to affect disorder in the resulting material. From analysis of the XANES spectra, the ceramic method showed the least amount of cation site disorder, followed by the citrate sol-gel method and co-precipitation method, respectively. Greater annealing temperatures resulted in an increase in cation site disorder, with the average coordination number of Al3+ and Ga3+ increasing while the average coordination number of Fe3+ decreased. Al1-xGaxFeO3 materials synthesized via the co-precipitation method showed the greatest amount of cation disorder, followed by the citrate sol-gel and high temperature ceramic techniques, respectively. The research presented in this thesis is among the first to examine a large number of materials from the relatively unexplored Al1-xGaxFeO3 system, and has contributed to the growing body of knowledge on the factors affecting cation site disorder in these materials and potentially other systems. Further, despite a simple rationale for understanding the features present in Al L2,3- and Ga K-edge spectra, these studies have shown how effectively XANES can be used to understand subtle changes in the atomic structure of solid-state materials.

A self-instructional training manual for conducting a multiple-stimulus without replacement (MSWO) preference assessment procedure was evaluated. The manual describes the MSWO procedure and how to summarize and interpret its results. Review questions that highlighted the key target behaviours were included at the end of each section of the manual, followed by an answer key. The manual was compared to a method description, adapted from the method sections of research articles published by DeLeon and Iwata (1996) and Roscoe, Fisher, Glover, and Volkert (2006). Eighteen undergraduate university students were assigned to two groups using a matched-pairs random assignment for the first 10 participants and random assignment for the next eight participants. Group 1 received the manual training first, followed by a crossover to the method description training if the pre-determined mastery criterion (85% correct or higher) was not met during simulated assessments. Group 2 received the training procedures in reverse order. The self-instructional manual was statistically significantly more effective than the method description in improving performance accuracy for conducting the MSWO procedure with an actor (a graduate student) simulating a person with an intellectual disability. Four out of nine participants in Group 1 met the mastery criterion after studying the manual only and one participant achieved mastery after the crossover. In contrast, none of the nine participants in Group 2 met the mastery criterion after studying the method description only and seven participants achieved mastery after the crossover. The remaining six participants all met the mastery criterion after observing a live demonstration of the procedure. Within each group, interventions were implemented in a modified multiple-baseline design across participants and the results showed that improvements occurred only after an intervention had been introduced. All participants who achieved mastery showed strong retention and generalization performances with novel actors and clients. On the social validity questionnaire, mean participant ratings showed that the manual was easier to follow and understand, and provided the necessary information for the assessment compared with the method description. The self-instructional manual has considerable potential as a low cost and effective tool to teach individuals to conduct the MSWO procedure.

When assessing preferences of individuals with developmental disabilities, choices can be described vocally or presented using objects or pictures in preference assessments. For individuals who are unable to perform auditory-visual discriminations and visual identity matching, objects instead of pictures or vocalizations need to be used for preference assessments to be effective. Considering the practical advantages of using pictures over objects, recent research has begun to focus on identifying and teaching skills needed for picture preference assessments. Although object-to-picture, picture-to-object, and generalized matching have been implicated as possible skills needed for picture preference assessments, further systematic studies are needed. The present study examined the relation between preference assessments (object vs. picture groups) and 5 discrimination skills. Based on direct paired-stimulus preference assessments completed at the beginning of the study, participants who could indicate their preferences with objects, but not with picture or vocal presentation, were assigned to the Object Group (n = 11); and participants who could indicate their preferences with both objects and pictures, but not vocal presentation, were assigned to the Picture Group (n = 9). The 5 discrimination tasks included: (a) object-picture matching and (b) its symmetry, picture-object matching; (c) generalized object-picture matching and (d) its symmetry, generalized picture-object matching; and (e) generalized identity picture-picture matching. All task stimuli were parts from everyday objects. Independent sample t-tests with Bonferroni correction showed that the percentages of correct responses were significantly higher in the Picture Group than in the Object Group on 4 of the 5 tasks (p < .01). Individual data showed that 8 of the 9 Picture Group participants met the pass criterion (80% or higher correct responses) on at least 1 discrimination task, with 6 participants passing 2 or more tasks. In contrast, only 1 of the 11 Object Group participants met the pass criterion on 1 discrimination task. The findings suggest that the effectiveness of picture preference assessments is not dependent on one specific discrimination, but possibly the ability to perform generalized matching.

Past research has shown that preference for a stimulus is correlated positively with reinforcer efficacy – more preferred stimuli tend to be more potent reinforcers. Researchers have recently examined the use of progressive ratio (PR) reinforcement schedules to evaluate preference. However, research on the concordance between preference and performance under a progressive ratio schedule is limited. Therefore, two experiments were conducted to extend this research. In Experiment 1 I compared the relative reinforcing efficacy of six stimuli obtained under a PR schedule to the mean preference hierarchy obtained through paired-stimulus preference assessments conducted before and after PR reinforcement sessions. In Experiment 2 I evaluated the PR schedule for quantifying the reinforcing value of three stimuli from Experiment 1 (i.e., one high, one medium, and one low preference stimulus). The results of Experiment 1 indicated that items that yielded higher breaking points and responses per minute were also more preferred. However, concordance between percent preference and breaking points and response rates for less preferred items was more variable. The results of Experiment 2 showed that high preference stimuli increased responding over baseline for all participants. However, low preference reinforcers also increased responding over baseline for some participants.

With climate change, forest soils of British Columbia (B.C.) will likely undergo significant increases in temperature. Changes in temperature may differentially alter steps of N cycling, altering the amount of N in various pools of the cycle. Furthermore, plant species may show a preference for certain N forms available in soils, such as ammonium, nitrate or organic N. Changes in soil N forms and plant N preferences can shift competitive interactions among conifer species in B.C. forests. Using a greenhouse incubation of forest soils from two elevations, I aimed to determine how temperature affects N cycling in soils that differ in temperature adaptations. With a conifer growth experiment where ammonium, nitrate and a mix of amino acids were applied to trees, I studied N form preferences and uptake rates of three conifer species from contrasting environments (Pseudotsuga menziesii, Picea sitchensis, and Picea engelmannii), and how N uptake in these species reacted to increases in soil temperature. Results show that the abundance of all N forms increased with temperature, but the response to warming was stronger in soils from a low elevation. Furthermore, ammonium and soluble organic N in soils increased faster with warming than nitrate. Nitrification potential was higher in the low elevation soil. This indicates that rates of soil processes, producing plant available N may increase with warming and the balance of different N forms may change. Differences in the abundance, composition, or activity of soil biota at these two locations likely caused dissimilar reactions to warming in two chemically and physically similar soils. Conifers exhibited preferences towards N forms, and these preferences are likely due to adaptation to the N form most available in native soils. On average, Douglas-fir showed preference for nitrate (a N form commonly found in warmer areas), Sitka spruce preferred ammonium (a N form high in cooler areas), and Engelmann spruce showed equal preference for organic N and ammonium (organic N is usually abundant in very cold areas). Preference as indicated by plant growth changed when species were grown at different temperatures, showing ability for acclimation in these conifers. Understanding that a soil’s history greatly affects its response to perturbation is important if we are to make predictions on how N cycling in soils may change with changing climate. Knowing how conifers utilize available soil nutrients at different temperatures will help to predict species’ future performance, composition and abundance in B.C. forests as soils warm and tree lines move north or to higher elevations. / Graduate / 0481 / 0817 / boczulst@uvic.ca