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The present study evaluated the effectiveness of and preference for choice during a response-acquisition tasks with children who have a developmental disability. The conditions compared involved (a) delivery of a high-preferred item identified at the start of the study (high preferred), (b) delivery of a high-preferred item identified immediately prior to each session (pre-session), (c) delivery of a high-preferred item identified immediately following each session (post-session), and (d) no delivery of a high-preferred item (control). The results regarding effectiveness were inconclusive due to high levels of responding during the control condition. The results regarding choice showed both participants preferred the pre-session choice condition, and one participant also preferred the high-preferred condition.

Thesis submitted by Jinrui Pan for the Degree of Doctor of Philosophy in the University of Manchester, and entitled, “Time and Risk Preferences: Theoretical Models and Applications.” Date of submission 2014.This thesis makes contributions to two important areas of behavioural economics, namely individual decision making over time and under risk. Following the Introduction, Chapter 2 presents a new discounting function for analysing intertemporal choice. Liminal discounting, the model developed here, generalises exponential discounting in a parsimonious way. It allows for well-known departures, whilst maintaining its elegance and tractability. It also can be seen as an extension of quasi-hyperbolic discounting to continuous time. A liminal discounter has a constant rate of time preference before and after some threshold time; the liminal point. A preference foundation is provided, showing that the liminal point is derived endogenously from behaviour. Chapter 3 proposes an axiomatic model featuring a differential treatment of attitudes towards risk and time. Such distinction has been strongly suggested by experimental research when studying intertemporal choice, since the future is inherently risky. In the proposed model, non-linear probability distortions are incorporated into a dynamic model with discounted utility. Time is captured by a general discounting function independent of probabilities and outcomes. Utility of outcomes is captured by standard vNM utility independent of time. A two-parameter probability weighting function captures intertemporal probabilistic risk attitudes, with one parameter being constant over time, the other being time-dependent. An index of optimism is derived that depends on both parameters, which allows to model the observed high risk tolerance for delayed lotteries. Further, a preference foundation is provided. Interestingly, the model allows behaviour to be consistent with discounted expected utility, when risk is sufficiently distant from the present.

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Class of 2009 Abstract / OBJECTIVES: To determine patient preference for the type of visit for the receipt of the influenza vaccine from the pharmacist and to determine patient preference for contact method for annual notification of the influenza vaccine program. METHODS: This was a descriptive study using a short telephone survey. The first dependent variable was the preferred type of visit comparing appointment-based and predetermined walk-in clinics. The second dependent variable was the preferred method of contact for annual notification of a pharmacist administered influenza vaccination program (telephone, US post mail, email). RESULTS: The telephone survey was completed by 206 patients. Overall, study participants preferred appointment-based visits ( 81.2 %; p < 0.05) compared to a predetermined walk-in clinic (18.8%). Overall, study participants significantly preferred to be contacted for annual notification of a pharmacist administered influenza vaccination program via telephone (75.7%; p< 0.05) compared with US post mail and email. Based on the percentages observed, the second preferred method of contact was email (12.6%) and US post mail was the third preferred method of contact (11.7%). CONCLUSIONS: Patient preference for type of visit for pharmacist-administered influenza vaccine was appointment-based as opposed to predetermined walk-in clinic based. Patient preference for contact method for annual notification was telephone as opposed to email or postal mail.

In this thesis I address several fundamental questions in sexual selection and mate choice theory, using the sandfly Lutzomyia longipalpis. I show that L. iongipalpis satisfies the criteria for a lek-breeding species. Males aggregated at sites near hosts which females visited to mate and feed, but a male's access to a resource did not appear to detennine his mating success. Females were free to reject unwanted males and male mating success was typically skewed. Field data suggest that the mating system may have evolved because of female preferences for larger leks, coupled with a hotspot-type mechanism: male distribution was correlated with resources availability, while females distribution was correlated with lek size. In the laboratory, females preferentially mated with middle-aged males. Within this age class, mating success was correlated with increased amounts of pheromone and increased investment in wing-fluttering. Across age classes, females appeared to gain a direct fitness payoff from their choice of mate through increased probability of fertilisation, but the presence of other mechanisms was not investigated. By testing simultaneously the predictions of current models using similar age males, I was able to assess their relative importance for the maintenance of female choice. I found weak evidence to support direct benefits: females that chose to mate with successful males survived longer post-oviposition than females with less successful mates. This did not translate into increased total longevity or increased fecundity. I found no evidence in favour of good-genes models: offspring of preferred males did not survive longer than offspring of less preferred males, nor were their daughters more fecund. Male attractiveness was, however, heritable: sons sired by preferred males achieved higher mating success than sons of less preferred fathers. These results suggest that a Fisherian mechanism is in part responsible for the maintenance of female mating preferences in L. iongipaipis.

Preference assessments are used in clinical settings to identify stimuli with reinforcing potential. The progressive-ratio schedule has shown to be useful in clinical assessments in identifying stimuli with stronger reinforcer efficacy that corresponds to formalized assessments.The current study utilized a progressive-ratio schedule to compare videos of high and low preference assessed by verbal reports of preference with college students. Results indicated breakpoints were higher for high preferred videos than low preferred videos for three out of five participants, but preference was not indicative of performance.

Many studies of natural landscape preference have demonstrated that qualities such as 'complexity' and 'naturalness' are associated with preference, but have struggled to define the key characteristics of these qualities. Recently, the development of software programs and digital techniques has offered researchers new ways of quantifying the landscape qualities associated with preference. Among them fractal geometry offers the most promising approach. Fractals have been defined as mathematical models of organic objects and patterns as opposed to the straight lines and perfect circles of Euclidean geometry found in man-made environments. Fractal patterns are mainly characterized by their dimension, which could be described as a statistical quantification of complexity. By applying this mathematical concept to digital images, several studies claim to have found a correlation between the fractal dimensions of a set of images and the images' preference ratings. Such studies have particularly focussed on demonstrating support for the hypothesis that patterns with a fractal dimension of around 1.3 induce better responses than others. However, much of this research so far has been carried out on abstract or computer-generated images. Furthermore, the most commonly used method of fractal analysis, the box-counting method, has many limitations in its application to digital images which are rarely addressed. The aim of this thesis is to explore empirically the suggestion that landscape preference could be influenced by the fractal characteristics of landscape photographs. The first part of this study was dedicated to establishing the robustness and validity of the box-counting method, and apply it to landscape images. One of the main limitations of the box-counting method is its need for image pre-processing as it can only be applied to binary (black and white) images. Therefore, to develop a more reliable method for fractal analysis of landscapes, it was necessary to compare different methods of image segmentation, i.e the reduction of greyscale photographs into binary images. Each method extracted a different structure from the original photograph: the silhouette outline, the extracted edges, and three different thresholds of greyscale. The results revealed that each structure characterized a different aspect of the landscape: the fractal dimension of the silhouette outline could quantify the height of the vegetation, while the fractal dimension of the extracted edges characterized complexity. The second part of the study focused on collecting preference ratings for the landscape images previously analysed, using an online survey disseminated in France and the UK. It was found that different groups of participants reacted differently to the fractal dimensions, and that some of those groups were significantly influenced by those characteristics while others were not. Unexpectedly, the variable most correlated with preference was the fractal dimension of the image's extracted edges, although this variable's predictive power was relatively low. The study concludes by summarising the issues involved in estimating the fractal dimensions of landscapes in relation to human response. The research offers a set of reliable and tested methods for extracting fractal dimensions for any given image. Using such methods, it produces results which challenge previous hypotheses and findings in relation to fractal dimensions that predict human preference, identifying gaps in understanding and promising future areas of research.