The evolution of multicellularity is an example of an evolutionary transition in individuality, in which a group of lower-level biological units (cells, in this case) emerges as a higher-level unit (the multicellular organism) with its own fitness, heritability and individuality. The volvocine green algae are a model system for the transition to multicellularity and for the evolution of cellular differentiation. Some of the developmental changes that collectively make up this transition have occurred more than once in the volvocine lineage; others have reverted from derived to ancestral states. The transition from cells to multicellular organisms began over 200 million years ago in this lineage, and the subsequent changes have been sporadic, with several important changes occurring early in the transition and some body plans remaining largely unchanged over long evolutionary time scales. Two suites of characters that differ among species within the genus Volvox have each evolved convergently or in parallel in lineages that diverged at least 175 million years ago. This complex history suggests that other origins of multicellularity may have involved important roles for cooperation, conflict and conflict mediation; parallel evolution of some traits; sporadic rather than constant change; and long-term coexistence of forms with different levels of complexity. Data from one species, Pleodorina starrii, support motility as a major selective pressure driving the the origins of cellular differentiation. Optimization of the proportion of soma in this species appears to be prevented by a constraint that prevents independent change in colonies with different numbers of cells. Finally, P. starrii presents an exceptionally high level of phenotypic variability, suggesting that the genotype-phenotype map has not completely shifted from the cell to the colony and that the transition to a new, higher-level individual in this species is incomplete.

The usual method of designing a solution for a problem, which applies general principles to a specific situation, tends to overlook the unique features of each situation and so must inevitably efface the very structure of what it means to create, and so resolve diversity and plurality into blank uniformity. This is grave problem which a renewed attention to the individuality of things might help resolve. This project considers the criticism of several thinkers (including John Duns Scotus, Martin Heidegger, Theodor Adorno, and J.C. Jones) on the schema of general and particular that undergirds the engineering design method. It then seeks to open up further the suggestions these thinkers have for a new approach to the design method not enthralled to an understanding of general categories, but grounded in a contemplation of the individual.

Computer models are used to simulate pedestrian behaviour for safety at mass events. Previous research has indicated differences between physical crowds of co-present individuals, and psychological crowds who mobilise collective behaviour through a shared social identity. This thesis aimed to examine the assumptions models use about crowds, conduct two studies of crowd movement to ascertain the behavioural signatures of psychological crowds, and implement these into a theoretically-driven model of crowd behaviour. A systematic review of crowd modelling literature is presented which explores the assumptions about crowd behaviour being used in current models. This review demonstrates that models portray the crowd as either an identical mass with no inter-personal connections, unique individuals with no connections to others, or as small groups within a crowd. Thus, no models have incorporated the role of self-categorisation theory needed to simulate collective behaviour. The empirical research in this thesis aimed to determine the behavioural effects of self-categorisation on pedestrian movement. Findings from a first study illustrate that, in comparison to a physical crowd, perception of shared social identities in the psychological crowd motivated participants to maintain close proximity with ingroup members through regulation of their speed and distance walked. A second study showed that collective self-organisation seemed to be increased by the presence of an outgroup, causing ingroup members to tighten formation to avoid splitting up. Finally, a computer model is presented which implements the quantified behavioural effects of self-categorisation found in the behavioural studies. A self-categorisation parameter is introduced to simulate ingroup members self-organising to remain together. This is compared to a physical crowd simulation with group identities absent. The results demonstrate that the self-categorisation parameter provides more accurate simulation of psychological crowd behaviour. Thus, it is argued that models should implement self-categorisation into simulations of psychological crowds to increase safety at mass events.

The ability to accurately interpret facial emotion is crucial to social being and our capacity to correctly interpret threat-related expressions has obvious adaptive value. Healthy individuals appear to process facial emotions rapidly, accurately and effortlessly, while individuals with schizophrenia often present with marked impairment in emotion processing. The hypothesis of continuity between schizophrenia and normal behaviour suggests that the signs and symptoms of the disorder also occur to varying, lesser degrees in the general population. This thesis presents a series of studies that explore the limits of facial emotion processing in healthy individuals, and its relationship with schizotypal personality traits. The first paper describes a set of three studies that use eye tracking techniques to explore the limits of rapid emotion processing. It is shown that we can quickly orient attention towards emotional faces even when the faces are task-irrelevant, presented for very brief intervals, and located well into peripheral vision. The remaining studies explore whether high schizotypes have similarities to individuals with schizophrenia in the way that they process facial emotion. High schizotypes were significantly less accurate at discriminating facial emotions and significantly more likely to misperceive neutral faces as angry, offering support for continuum models of visual hallucinatory experiences. A further study revealed that high relative to low schizoptypes feel as though they are exposed to angry faces for longer. It is argued that this experience itself may serve to maintain hypervigilance to social threat. Finally, laterality biases during face perception were explored. Contrary to the predictions of continuum models of schizophrenia, high schizotypes had an increased left side / right hemisphere bias for face processing. In summary, the thesis offers partial support for the hypothesis of continuity between the impairments in emotion discrimination observed in individuals with schizophrenia, and normal, healthy variation in facial emotion processing.

Self-affirmation has been successfully applied as a technique to promote open processing of health-risk information. However, much research in this area has explored the uniform effectiveness of self-affirmation interventions. The current thesis adds to existing literature by exploring whether different aspects of self-regard moderate self-affirmation effects. Study 1 (N = 328) investigated whether global self-esteem moderated the effectiveness of self-affirmation at promoting openness to a message highlighting the risks of insufficient exercise. Global self-esteem was found to be a significant moderator. Self -affirmed individuals with low global self-esteem reported more positive attitudes and intentions towards increasing their exercise behaviour, together with less message derogation; there was no effect of self-affirmation for those high in global self-esteem. Study 2 (N = 166) extended this research by exploring the moderating impact of a variety of self-regard aspects on self-affirmation effects. Contingent self-esteem emerged as a significant moderator. Thus self-affirmed individuals with low contingent self-esteem reported more positive attitudes and perceptions of control towards increasing their exercise behaviour; there was no evidence that self-affirmation promoted openness for those high in contingent self-esteem. Study 3 (N = 139) explored whether experimentally induced contingent self-esteem moderated the effectiveness of a self-affirmation manipulation at promoting open processing of a message detailing the risks of insufficient exercise. There was no evidence of this for any of the outcome variables. Lastly, study 4 (N = 125) investigated whether the moderating impact of global and/or contingent self-esteem on self-affirmation effects would extend to a message detailing the risks of alcohol consumption. Both self-esteem aspects moderated the impact of the self-affirmation manipulation on perceptions of behavioural control regarding reducing the amount of alcohol consumed. Moreover, self-affirmation was associated with lower levels of alcohol consumption at follow-up for those with low global self-esteem, and with higher alcohol consumption at follow-up for those with high global self-esteem.

Exercising to improve one's appearance has been consistently associated with negative body image (e.g., Tiggemann & Williamson, 2000). However, little is known about either the processes underlying this association, or the causal direction of the effects. This thesis draws upon both self-determination theory (SDT; Deci & Ryan, 2000) and objectification theory (Fredrickson & Roberts, 1997) in order to investigate the role of regulations for exercise and self-objectification in the link between appearance goals and body image. The thesis examines both individual variations in these constructs, and their influences on body image among young women, utilising cross-sectional, longitudinal and experimental methodologies with both student samples and a community sample of gym-users (Chapter 2 and 3). It also considers factors in the exercise environment that can influence regulations of behaviour and feelings of self-objectification, using the physical education classes of adolescent girls as an exemplar (Chapter 4 and 5), drawing upon recent work on objectifying environments (Moffitt & Syzmanski, 2011) and the existing self-determination theory literature on motivation in physical education. The four empirical papers highlight in particular the importance of introjected, or guilt-based, regulation in the link between appearance goals and negative body image, and illuminate the associations with self-objectification. Furthermore, they highlight the negative impact that an objectifying and non-autonomy supportive environment can have on girls' engagement in and enjoyment of physical education, and on their body image. The theoretical and practical implications of these findings are discussed, in relation to an integration of self-determination and objectification theories as well as the potential for autonomy-supportive, non-objectifying exercise interventions that de-emphasise guilt and emphasise the intrinsic value and joy of physical activity.

The brief introductory chapter attempts to motivate the project by pointing to (a) the intuitive appeal and importance of the notion of an object (that is, a “paradigmatic” individual), and (b) the need – for the sake of progress in at least two important debates in ontology – to replace this notion with a series of related notions of individuals of different sorts. Section One of Chapter Two aims to accomplish two primary tasks. The first is to clarify the intensions of three often employed but ambiguous categorical terms: ‘individual’, ‘particular’ and ‘object’, with emphasis on the third, which is often taken to be of particular philosophical significance. I carry out this clarificatory task by weighing various positions in the literature and arguing for explications of each notion that are maximally economical and neutral, that is, explications which (a) overlap as little as possible with other important ontological notions and (b) do not require us to take a stand on any apparently intractable (but not directly relevant) debates (e.g. on the problem of realism vs. nominalism about universals). The second task of 2.1 is to delineate the various ontological distinctions that will be turned, in Chapter Four, into the “dimensions” of which the ontological framework I will be advocating there is composed. The delineation of these distinctions takes place naturally in the course of attempting to characterize the notion of an object (an intrinsically unified, independent concrete particular) and to distinguish it from the notions of an individual and a particular, in spite of the fact that objects are both individuals and particulars. In the second section of Chapter Two I illustrate the centrality of the notion of an object in Ontology by showing how that notion figures in the debate over the existence of artifacts. I argue that progress in this debate has been hindered by the way it has been framed, and that seeing the issue as concerning not whether artifacts exist but whether artifacts are objects (in the sense outlined in 2.1) enables us to better appreciate and accommodate the different perspectives of the debate’s participants. At the same time, this way of dissolving the dispute makes clear that existence is not limited to entities that fall under the relevant concept of an object, foreshadowing the pluralistic ontological framework to be developed in Chapter Four. Chapter Three pronounces on a second debate in ontology, in which three positions concerning the correct ontological assay of the class of intrinsically unified independent concrete particulars (objects) are in competition with each other. My conclusion is that none of the three positions succeeds, since each faces fairly serious difficulties. I suggest that the (or at least one major) root of our inability to locate the correct ontological assay is the inclination to treat all ontologically significant entities as objects in the indicated sense, and the corresponding inclination to attempt to give an ontological assay that covers all objects, neglecting important differences between distinct types of individuals. Chapter Four begins by displaying in greater detail the considerations (canvassed very briefly in the introductory chapter) that make the notion of an object appear to be indispensible. However, the results of the second section of Chapter Two and of the entirety of Chapter Three have already shown two areas in which the notion of an object tends to lead to confusion. So a tension emerges between the prima facie necessity of the notion and the reasons we have found for thinking that this notion either is itself problematic or at least tends to cause problems for other issues in Ontology. The remainder of Chapter Four consists in explaining my strategy for moving forward. Briefly, this strategy involves replacing the notion of an object with a series of concepts applicable to individuals of various types. Each of the components belonging to a given “individual-concept” is drawn from one or another side of one of the ontological distinctions that together form an overall ontological framework, and which components are involved is a matter to be determined by examining the conceptual demands imposed by the various practices (explanatory or otherwise) which we engage in, that require us to appeal to individuals of the type in question. The resulting “pluralistic” ontological framework provides a way of situating and relating types of individuals that both avoids the confusions that the single general concept of an object leads to, and is capable of indicating the varying degrees of “ontological robustness” or “object-like-ness” of any given type of individual. I conclude by suggesting how the framework I am advocating can be elaborated on and put to use in further research.

The brief introductory chapter attempts to motivate the project by pointing to (a) the intuitive appeal and importance of the notion of an object (that is, a “paradigmatic” individual), and (b) the need – for the sake of progress in at least two important debates in ontology – to replace this notion with a series of related notions of individuals of different sorts. Section One of Chapter Two aims to accomplish two primary tasks. The first is to clarify the intensions of three often employed but ambiguous categorical terms: ‘individual’, ‘particular’ and ‘object’, with emphasis on the third, which is often taken to be of particular philosophical significance. I carry out this clarificatory task by weighing various positions in the literature and arguing for explications of each notion that are maximally economical and neutral, that is, explications which (a) overlap as little as possible with other important ontological notions and (b) do not require us to take a stand on any apparently intractable (but not directly relevant) debates (e.g. on the problem of realism vs. nominalism about universals). The second task of 2.1 is to delineate the various ontological distinctions that will be turned, in Chapter Four, into the “dimensions” of which the ontological framework I will be advocating there is composed. The delineation of these distinctions takes place naturally in the course of attempting to characterize the notion of an object (an intrinsically unified, independent concrete particular) and to distinguish it from the notions of an individual and a particular, in spite of the fact that objects are both individuals and particulars. In the second section of Chapter Two I illustrate the centrality of the notion of an object in Ontology by showing how that notion figures in the debate over the existence of artifacts. I argue that progress in this debate has been hindered by the way it has been framed, and that seeing the issue as concerning not whether artifacts exist but whether artifacts are objects (in the sense outlined in 2.1) enables us to better appreciate and accommodate the different perspectives of the debate’s participants. At the same time, this way of dissolving the dispute makes clear that existence is not limited to entities that fall under the relevant concept of an object, foreshadowing the pluralistic ontological framework to be developed in Chapter Four. Chapter Three pronounces on a second debate in ontology, in which three positions concerning the correct ontological assay of the class of intrinsically unified independent concrete particulars (objects) are in competition with each other. My conclusion is that none of the three positions succeeds, since each faces fairly serious difficulties. I suggest that the (or at least one major) root of our inability to locate the correct ontological assay is the inclination to treat all ontologically significant entities as objects in the indicated sense, and the corresponding inclination to attempt to give an ontological assay that covers all objects, neglecting important differences between distinct types of individuals. Chapter Four begins by displaying in greater detail the considerations (canvassed very briefly in the introductory chapter) that make the notion of an object appear to be indispensible. However, the results of the second section of Chapter Two and of the entirety of Chapter Three have already shown two areas in which the notion of an object tends to lead to confusion. So a tension emerges between the prima facie necessity of the notion and the reasons we have found for thinking that this notion either is itself problematic or at least tends to cause problems for other issues in Ontology. The remainder of Chapter Four consists in explaining my strategy for moving forward. Briefly, this strategy involves replacing the notion of an object with a series of concepts applicable to individuals of various types. Each of the components belonging to a given “individual-concept” is drawn from one or another side of one of the ontological distinctions that together form an overall ontological framework, and which components are involved is a matter to be determined by examining the conceptual demands imposed by the various practices (explanatory or otherwise) which we engage in, that require us to appeal to individuals of the type in question. The resulting “pluralistic” ontological framework provides a way of situating and relating types of individuals that both avoids the confusions that the single general concept of an object leads to, and is capable of indicating the varying degrees of “ontological robustness” or “object-like-ness” of any given type of individual. I conclude by suggesting how the framework I am advocating can be elaborated on and put to use in further research.

Thesis--M. Phil., University of Hong Kong, 1980.

Much of biology, especially evolutionary theory, makes assumptions about the individuality of living things. A population, for example, is made up of individuals. Those individuals sometimes reproduce, creating new individuals. The very use of these concepts requires that living individuals can be distinguished both synchronically and diachronically. There are many examples in nature, however, in which a living system is present, but it is not clear how to understand that system's individuality. Plants, fungi, colonial marine invertebrates, insect colonies, and symbiosis are all classic cases that have puzzled biologists interested in understanding their population structure and evolution. Scientific exploration of these issues has connections with traditional philosophical terrain, particularly the ontology of persistence and the nature of individuality broadly construed. A biologically informed philosophical literature has arisen in recent years, aimed at understanding the nature of biological individuality and its role in biological theorizing. My dissertation makes two kinds of contributions to this current literature. One contribution is theoretical, reframing our thinking about biological individuality. I distinguish between two categories of individuality and argue that they play different roles in theorizing about nature. One important kind of individual is that of the organism, understood as an entity that persists through space and time, takes in and processes resources from the environment, and maintains physiological autonomy. Another important kind of individual is that of the evolutionary individual, understood as an entity that has the capacity to participate in processes of natural selection. Distinguishing between these two types of individuality has theoretical utility, keeping clear the distinctive kinds of biological processes that individuals engage in. The other contribution of my dissertation involves detailed natural historical analysis of three kinds of problem cases. Using the framework articulated earlier in the dissertation, I assess the individuality of symbioses between larger organisms and their microbial associates, mushroom-producing fungi, and the classic case of ant colonies. The combined result of the assessments is a hierarchical pluralism about biological individuality. / Philosophy