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Les persévérants (Ferron et Baer, 2014) est une série-documentaire originairement diffusée sur ICI RDI en 2014. Elle propose de suivre l’expérience de neuf élèves du premier cycle du secondaire en difficulté scolaire dans le cadre d’un programme en Santé globale de promotion de la persévérance scolaire. Les persévérants est envisagé comme une production exemplaire qui interroge les effets des pratiques actuelles en psychologie dans le contexte télévisuel. D’abord, cette thèse élabore un « laboratoire d’étonnement » comme méthodologie originale pour l’analyse de ce matériau télévisuel. Cette méthodologie implique un ensemble d’instruments d’analyse qualitative et de discussions collectives afin d’assurer la rigueur de l’étude. Ensuite, les pratiques des « experts » du programme ainsi que la qualité de la participation des élèves sélectionnés sont analysées en termes d’expériences de domination (Martuccelli, 2004), de Student voice (Cook-Sather, 2006; Fielding, 2004) et d’agir volitionnel (Leont’ev, 2005). Nos résultats mettent en lumière différents mécanismes contraignant la participation et la prise de parole des élèves en difficulté dans le programme télévisuel. _____________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : décrochage scolaire, élèves en difficultés, programme télévisé, Laboratoire d’étonnement, Voix de l’élève, domination, agir volitionnel

This thesis aims to further our understanding of the role that intuition plays in human reasoning when making probability judgements. It attempts to: a) gain a better understanding of the cognitive processes underlying these judgements, b) determine how individual differences impacts the logicality of these judgements, and c) test original and theoretically-driven ways to increase logical intuitions in probability judgements. Classically, it is assumed that people make biased judgements because they rely on an intuitive thinking system (System 1) and apply the representativeness heuristic to make conjunctive probability judgements. In contrast, logical judgements are assumed to arise from the use of deliberation (System 2) to overrule the prepotent heuristic response and replace it with a logical one. Recent research; however, has challenged this claim and instead proposes that our intuitions do not always lead us astray. In fact, they can reflect a sensitivity to logic that is implicit, and potentially happens automatically and outside of awareness. This thesis takes this notion one step further and asks whether it is the slower, more deliberative, thinking system which may be vulnerable to prior beliefs and biases. A series of five experiments examined the relative impact of heuristic and logical considerations on probability judgements. The results indicated that people are readily able to detect the conflict underlying intuitive and deliberative assessments, and that people effortlessly engage in deliberative processing, which suggests they are not simply cognitive misers who fail to reason in line with the principles of logic because they either lack the cognitive ability or the motivation to do so. The results also supported the idea that people can intuit logical judgements (i.e., judgements in accordance with the laws of probability) when they rely on System 1 thinking; however, when they deliberate or use System 2 thinking, that is when the heuristic biases their judgements.

Le trouble du spectre de l'autisme (TSA) se définit par des difficultés sociocommunicationnelles et par la présence de comportements ou d'intérêts restreints ou répétitifs (Association américaine de psychiatrie [APA], 2013). Ainsi, les parents doivent s'investir dans la réadaptation de leur enfant et réorganiser leur quotidien de manière à pallier l'altération fonctionnelle liée au TSA (des Rivières Pigeon, Courcy, Boucher, Laroche, & Poirier, 2015). Afin de soutenir les parents dans ces nombreuses responsabilités, les grands-parents sont souvent amenés à s'impliquer dans la prise en charge des soins de l'enfant (Rousseau, 2009). Les interactions entre les grands-parents et l'enfant présentant un TSA peuvent toutefois comporter des particularités, en raison même des déficits sociaux de l'enfant. Par contre, des études ont démontré que ces enfants présentent une sensibilité aux stimuli sociaux envers des adultes significatifs, et ce, en dépit de l'altération sociocommunicationnelle observée (Caron, Royer, & Forget, 2014). Ainsi, les enfants ayant un TSA présentent une tendance à varier leur comportement en fonction de l'attention reçue des parents, des éducateurs et des enseignants (Duval & Forget, 2005; Forget & Rivard, 2010; Poirier & Forget, 1996). Bien que les grands-parents soient identifiés comme des personnes significatives, aucune étude ne s'est intéressée à la sensibilité sociale des enfants présentant un TSA lorsqu'ils interagissent avec leur grand-parent. Cette étude vise à quantifier la sensibilité sociale d'enfants âgés de trois à six ans lorsqu'ils interagissent avec leur grand-parent (n = 6 dyades) dans une situation autonome, pratique et sociale. Les comportements de l'enfant et de son grand-parent sont d'abord observés en milieu naturel à huit reprises à raison de 90 minutes chaque fois. La sensibilité sociale est mesurée par une analyse de régression linéaire simple à l'aide de la loi généralisée de l'appariement et des analyses descriptives sont utilisées pour documenter les comportements observés. Les résultats indiquent que les enfants de cette étude ont une préférence pour les comportements sociaux comparativement aux comportements non-sociaux. La préférence pour les comportements sociaux correspond à la notion de biais dans le cadre de la loi généralisée de l'appariement. Parmi les comportements recensés, les enfants manifestent le plus souvent des réponses aux demandes des grands-parents et ils cherchent à maintenir l'échange avec eux. Dans une plus faible mesure, ils vont eux-mêmes initier l'interaction avec le grand-parent. Le taux de comportements sociaux varie selon les conditions; les enfants interagissent ainsi davantage lorsque le contexte est favorable à un échange soit lors d'une condition sociale. Par contre, ils ne modifient pas leurs comportements en fonction de l'attention donnée par leur grand-parent. Il n'y a pas de différence de sensibilité sociale selon les conditions, qu'elles soient autonome, pratique ou sociale. Par ailleurs, les tâches ont été choisies en fonction de la capacité de l'enfant et non pas pour induire des apprentissages. Il est donc possible que les enfants ne modifient pas leurs comportements en fonction de l'attention du grand-parent lorsqu'il s'agit d'une tâche acquise comme le font les personnes avec un TSA de niveau léger en contexte de classe (Poirier & Forget, 1996). En effet, un enfant qui maîtrise une tâche peut la faire de manière indépendante, et ce, peu importe les contingences présentes dans l'environnement au même moment. Cet essai est composé d'une recension des écrits scientifiques sur les grands-parents d'enfants ayant un TSA et sur la sensibilité sociale des enfants. Ensuite, un article reprend les points centraux de cette recension et présente la méthode et les résultats obtenus. L'ensemble des résultats est discuté de manière plus approfondie dans la dernière partie abordant les apports et les limites de cette étude de même que des recommandations pour de futures recherches. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : autisme, grand-parent, sensibilité sociale, comportements sociaux

Judging the truth of incoming information is one of the most challenging and important tasks that people face every day. How do people decide what is true and what is not? When constructing truth judgements, people use both declarative information and the subtler cues that accompany information processing. These subtle, non-content-based cues that make information feel truer are termed "truth effects". This thesis uses trivia statements to investigate the robustness of two such non-probative truth effects driven by repetition (the illusory truth effect) and concrete language (the linguistic concreteness effect). Neither concreteness nor repetition provide substantive evidence, yet people believe repeated statements more than new ones, and concretely worded statements feel truer than their abstract counterparts. Truth effects can have direct implications in our digital world, where information may be spurious, and communicators can enlist subtle cues to persuade the addressee without detection. Throughout the thesis I apply open methods that have the potential to increase the quality, replicability, and transparency of research. In Chapter 2, I set out to replicate and extend the linguistic concreteness effect. Across two experiments I did not observe an effect larger than the smallest effect size of interest. Therefore the remainder of the thesis focuses on the illusory truth effect. Chapter 3 uses systematic mapping to synthesise and catalogue the entire illusory truth literature in terms of methods, findings, and transparency. The results reveal a lack of standardisation in the methodology employed, and of transparency in reporting. I also find that greater diversity of stimuli and participants is required for generalisability. In Chapter 4, my final study used a longitudinal design to test whether the delay between repetitions moderates illusory truth. Contrary to previous claims, I find that across four intervals (immediately, one day, one week, one month) the effect diminishes as delay increases. This thesis contributes to knowledge by providing an overview of the current state of truth effects research. It demonstrates that there is considerable cause to doubt the existence of a linguistic concreteness effect, and by implication, there is reason to be sceptical about other truth effects based on subtle manipulations. In contrast, this thesis establishes confidence that the illusory truth effect is robust but reduces with time. This finding has implications for the mechanisms thought to underlie truth effects. Overall, the results suggest that when truth effects research uses rigorous, transparent, and unbiased methods, it paints a different picture from that of the existing literature.

Influenza (flu) is a highly infectious respiratory virus, posing a serious and increased risk for health complications and premature death. To protect against the spread of the virus, 'at-risk' groups such as Healthcare Professionals should be vaccinated. Ensuring improved immunity within this target group may help to reduce the risk of nosocomial transmission to patients (Goins et al., 2011). Yet, despite annual flu campaigns, the recommended 75% vaccine coverage rate remains a challenge. Typically, psychological frameworks such as the health belief model and the theory of planned behaviour are used to understand, predict and explain psychological, social and environmental factors of vaccination decisions. However, research often only goes as far as to predict vaccination uptake, and there is a need for an increase in scientifically-led theory-based interventions (Corace et al., 2016). This thesis applies the theoretical lens of self-determination theory (SDT), a general theory of human motivation (Ryan & Deci, 2000), to investigate the role of autonomy in Healthcare Professionals' decisions to get vaccinated against the flu. In addition, it seeks to understand how encouraging an autonomous decision may impact behavioural intentions to receive the flu vaccination. Its contribution begins with a systematic review identifying and assessing the effectiveness of existing health-related behavioural interventions rooted in SDT, highlighting that autonomy is an important factor for positive behavioural outcomes and sustained behaviour change. It provides insight into strategies and measures for the development of behavioural interventions, contrasting environments which support choice or force change. Based on these findings, four cross-sectional survey studies are reported, which all contributed to the development of a psychometric scale measuring Healthcare Professionals' flu vaccine motivations. The scale was distinct from, and contributed over and beyond, other psychosocial measures of flu vaccination behaviour and can be used to understand the motivation of both vaccine acceptors and vaccine deniers. Findings support the recommendation that assessing autonomous regulation is essential for understanding the psychological drivers of vaccine uptake (Denman et al., 2016), adding that additional regulations of autonomy, such as introjection (guilt avoidance) and external control are also important for assessing healthcare professionals' flu vaccine decisions. The final contribution of the thesis, in response to the increased need for scientifically led theory-based interventions, includes a pilot and an experimental study which developed and tested different communication styles aimed at promoting healthcare professionals' vaccine uptake. Reported findings reveal that communication messages supporting the need for autonomy, compared to messages using high controlling language, reduce the threat to freedom of choice. Autonomy-supportive messages have a positive impact on the change in behavioural intentions to vaccinate against the flu when autonomous and introjection regulations are low. Thus, the present thesis provides a new and important avenue to understand the motivation driving healthcare professionals' flu vaccine decisions, and it provides theoretically driven foundations for a future behaviour change intervention, incorporating autonomy-supportive communication styles.

The research in this thesis describes a microgenetic investigation of thought as it occurs in and through objects and informed by work in distributed cognition and interactivity. The thesis opens with a detailed survey of the arguments in cognitive philosophy around the ontological locus of cognition. I advance the conclusion that many of the open questions will not be solved by empirical methods and suggest a pragmatist approach. Four empirical studies are reported: Three laboratory-based studies which feature traditional problem-solving tasks found often in cognitive psychology and one which examines an artist solving problems which arise over the course of the artistic process. Each of the studies combines quantitative analysis with qualitative analysis of video recorded material to describe thinking in an open cognitive ecosystem. The first study reports performance on a word production task and finds that engagement with external representations is crucial to scaffold performance. The second study uses anagrams to assess the nature of that engagement and concludes a non-agentic model of mere luck is not sufficient. Study three examines performance on an insight problem and suggests that when the problem is not one which is easily scaffolded by material objects, systems form around other types of external scaffold. The final study tracks thought as it unfolds through making of a flower in an artist's atelier. The findings of all the studies support the notion that cognition emerges in the form of material traces and actions on the world. The thesis introduces and develops two concepts-microserendipity and exaptative action-that offer a new perspective on the nature of problem solving and creativity. These concepts bring in sharp relief environmental chance in creativity when it is enacted; the methodology employed in the empirical work reported here also permits the identification of events when environmental chance is unnoticed. These phenomena operate outside the conscious observation of the problem solver so they cannot be tracked through traditional methods. The work reported here introduces kinenoetic analysis that trace in micro detail the dynamic transactional coupling between thought and objects that chart the origin of new ideas. The knowledge that the participant generates through the movement of objects mirrors the knowledge gained by the experimenter by these movements. The last chapter introduces kinemorphism as part of a qualitative description of the creative trajectory of an artist working with clay: form is unstable and arises out of action. Such a perspective suggests that what is produced cannot be explained by a reductive process that focuses on only one or the other, but rather must take into account the relationship which arises through action. Creativity from this perspective is transactional and relational. In terms of theoretical contributions, I cast doubt on an agent centric view of interactivity which posits an uncomplicated augmentative relationship between things beyond and within the brain and suggests instead a transactional approach to knowledge acquisition. These lead to novel observations on the role of the experiment in research in situated cognition. Reflections on the pluralistic method of kinenoetic analysis are offered and directions for future research are outlined.

The processes involved in empathy, the ability to appreciate others’ inner experiences and respond appropriately to them, are central to the formation and maintenance of successful interpersonal relationships and communities (e.g., Castano, 2012). These skills typically emerge in childhood but can also be developed in adults (Teding van Berkhout & Malouff, 2016). Engagement with fiction may enhance adults’ empathic skills because readers mentally simulate the social experiences depicted in stories (Oatley, 1999). Several studies have identified positive relationships between exposure to fiction and empathic abilities (Mumper & Gerrig, 2017), whereas causal findings are more mixed (see Dodell-Feder & Tamir, 2018), and this may reflect heterogeneity across both fiction stimuli and empathy measures. The present research took a multidimensional approach to nvestigating the nature of relationships between fiction and empathic abilities. Study 1 examined correlations between self-report empathic abilities and fiction habits. Participants (N = 404) completed a multidimensional task measure of fiction media-exposure and answered questions about fiction-engagement and empathic tendencies. Results revealed divergent associations between narrative modes and empathic abilities, and fiction media-exposure positively predicted the tendencies to become absorbed in narratives and to behave altruistically. Study 2 (N = 308) assessed the relationship between fiction-exposure and performance on a behavioural measure of empathic accuracy (the ability to accurately interpret mental state content) when using mentalising or experience-sharing inferencing processes. Results showed that the two strategies entailed similar levels of error but in opposite directions. Empathic accuracy varied as a function of target and valence and was positively predicted by lifetime fiction-exposure. Study 3 investigated the causal impact of immersion. An initial pilot study, a text pretest, two manipulation pilots, and an experiment (total N = 224), were conducted. Ultimately, immersion levels, measured across three dimensions, were not successfully manipulated. Immersion dimensions correlated with self-report and behavioural empathic ability measures, and an exploratory analysis revealed an effect of reading on empathic accuracy for story characters’ mental states. Collectively, the studies provide support for the hypothesis that fiction-exposure and empathic abilities are associated, but limited evidence of causation. ethodological limitations, other influential variables, and research implications are discussed. The assumption that fiction and empathy are beneficial is critiqued, and future research avenues suggested.

Transcranial direct current stimulation (tDCS) is used as a noninvasive tool to modulate brain excitability in humans. Recently, several studies have demonstrated that tDCS applied over the motor cortex also modulates spinal neural network excitability and therefore can be used to explore the corticospinal control acting on spinal neurons. Previously, we showed that reciprocal inhibition directed to wrist flexor motoneurons is enhanced during contralateral anodal tDCS, but it is likely that the corticospinal control acting on spinal networks controlling wrist flexors and extensors is not similar. The primary aim of the study was to explore the effects of anodal tDCS on reciprocal inhibition directed to wrist extensor motoneurons. To further examine the supraspinal control acting on the reciprocal inhibition between wrist flexors and extensors, we also explored the effects of the tDCS applied to the ipsilateral hand motor area. In healthy volunteers, we tested the effects induced by sham and anodal tDCS on reciprocal inhibition pathways innervating wrist muscles. Reciprocal inhibition directed from flexor to extensor muscles and the reverse situation, i.e., reciprocal inhibition, directed from extensors to flexors were studied in parallel with the H reflex technique. Our main finding was that contralateral anodal tDCS induces opposing effects on reciprocal inhibition: it decreases reciprocal inhibition directed from flexors to extensors, but it increases reciprocal inhibition directed from extensors to flexors. The functional result of these opposite effects on reciprocal inhibition seems to favor wrist extension excitability, suggesting an asymmetric descending control onto the interneurons that mediate reciprocal inhibition.

In the absence of effective treatments for memory disorders including dementia, NIBS methods are being tested for studying and enhancing memory. Anodal transcranial direct-current stimulation (atDCS) is a safe, non-invasive method of stimulating the brain and modulating neural activity through electrodes placed on the scalp. Controversy has surrounded the implementation of atDCS as a research and clinical tool because of inconsistency in effects and a limited understanding of atDCS parameters and mechanisms. Heterogeneity in atDCS parameters across studies could contribute to the inconsistency in effects. Thus, the current research included a systematic ethodological investigation of atDCS as a potential research and clinical tool. Two meta-analyses and a set of five methodological experiments analysed the efficacy of atDCS given a consistent set of parameters. In younger adults, atDCS led to a weak and volatile effect under certain conditions that fluctuated with modifications to verbal stimuli and sample size. While there was a robust improvement in memory following atDCS over the left PFC in Experiment 1, this effect did not remain consistent in direct and conceptual replications. The metaanalyses provided support to this investigation by demonstrating that when effect sizes were pooled together across all eligible published studies, the average effect size was close to zero. When only the studies in the current investigation were pooled together, the effect size was larger but also non-significant. Thus, the results inform future considerations of atDCS as a research and clinical tool and provide recommendations for the limited applications of atDCS with a framework for applying effective parameters that take into account individual differences. Furthermore, through the course of the investigation of atDCS, novel findings about episodic memory processes and neural correlates were revealed, confirming the importance of activity in the ventrolateral prefrontal cortex (VLPFC) to episodic memory formation. These findings on VLPFC function were further extended with an investigation of the cognitive mechanisms of atDCS effects on VLPFC 3 function in Chapter 6 and an examination of the time window and process in the VLPFC that was most crucial to memory formation with repetitive transcranial magnetic stimulation (rTMS) in Chapter 7. Together, the findings contributed to developing a clearer understanding of atDCS effects on episodic memory and the episodic processes that occur in the VLPFC. This understanding can inform future research in NIBS with other cognitive functions and the development of memory nterventions that can target the VLPFC.

Cette thèse porte sur la carrière et la pensée de l'artiste canadien-français Napoléon Bourassa (1827-1916), qui s'est fait connaître à titre de peintre, architecte, critique d'art, écrivain et enseignant. Cette étude cherche à retracer la position intellectuelle adoptée et le rôle culturel joué par Bourassa dans la société montréalaise de la seconde moitié du XIXe siècle. De façon plus spécifique, cette thèse vise l'évaluation de la contribution artistique, pédagogique et théorique de l'artiste à la vie culturelle montréalaise entre 1855 et 1890. Le plan de la thèse comprend deux parties principales, qui témoignent de deux étapes distinctes dans la carrière de l'artiste. La première partie de la thèse porte sur les quinze premières années (1855-1869) de la carrière de Bourassa, après un séjour d'études en Europe. À cette époque d'effervescence culturelle, les associations et les bibliothèques publiques se multiplient, le domaine de l'instruction publique connaît des réformes importantes, alors que plusieurs nouveaux périodiques paraissent. Les deux chapitres constituant cette section illustrent la participation de Bourassa à différentes entreprises culturelles et ses liens avec les autres intellectuels montréalais de la période. Le premier chapitre aborde les débuts de l'artiste dans la sphère culturelle montréalaise, en examinant sa contribution au mouvement associatif, sa production littéraire et sa participation au développement du milieu de l'art. Cette analyse montre que Bourassa prend part à un réseau d'intellectuels francophones voué à l'essor et à la promotion d'une culture canadienne-française basée sur le sentiment nationaliste et la religion catholique. Le chapitre deux étudie les diverses facettes de sa carrière dans le domaine artistique, soit sa production picturale et scuIpturale, ses activités d'enseignement du dessin et des beaux-arts, ses critiques d'art publiées dans la Revue canadienne, et sa participation à l'Exposition universelle de Paris en 1867. Ce chapitre démontre que Bourassa fait sa marque dans le domaine cuIturel montréalais moins par l'impact de sa production artistique que par sa réflexion critique sur la pédagogie et le développement des arts au Canada. La seconde partie de la thèse porte sur la période s'étendant de 1870 à 1890, alors que le mouvement associatif montréalais s'essouffle et que les effets de l'industrialisation se manifestent de plus en plus. Cette section étudie les différentes activités de Bourassa qui montrent que l'artiste désirait participer à l'essor d'une école canadienne des beaux-arts. Le chapitre trois met en lumière les principales thèses défendues par Bourassa dans ses essais sur l'esthétique et l'histoire de l'art qu'il rédige à partir de 1870. Cette étude permet de constater que la pensée de Bourassa sur l'art est teintée des idées des théoriciens français du renouveau de l'art religieux (A.-F. Rio, C.-J. Félix), qui prônent un retour à la peinture murale et le recours à une forme d'art hiératique inspirée de l'art pré-renaissant. Le chapitre quatre analyse les principales entreprises de décor mural auxquelles Bourassa prend part entre 1870 et 1890, c'est-à-dire la décoration de la chapelle de l'Institut Nazareth, celle de la chapelle Notre-Dame de Lourdes, le projet de décor du Palais législatif, et celui de la cathédrale Saint-Hyacinthe-le-Confesseur. L'examen des deux premiers décors religieux révèle l'emploi, par Bourassa, d'un style hiératique inspiré de l'art pré-renaissant en accord avec l'enseignement des théoriciens du renouveau de l'art chrétien. Les études préparatoires des deux autres projets, qui n'ont jamais été réalisés, démontrent que l'artiste désirait travailler dans un style différent, plus près du naturalisme. Le chapitre cinq rend compte des différentes contributions de Bourassa à l'enseignement des beaux-arts et des arts industriels, et met en évidence les préceptes pédagogiques soutenus par l'artiste. Cette étude montre que Bourassa met de l'avant deux modèles pédagogiques différents pour la formation des ouvriers (dans une institution d'enseignement) et des artistes (dans l'atelier d'un maître). Quant aux préceptes pédagogiques chers à l'artiste, ils reposent surtout sur le principe d'émulation et sur l'apprentissage du dessin d'après modèles. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Napoléon Bourassa, Art, Théorie, Enseignement, Peinture murale, Canada.

This thesis investigates the process of decision-making in relation to complex tasks and considers the important role which dynamic information and real-time feedback play in shaping response behaviour and adaptation within such environments. Through empirical studies, the thesis explores the extent to which decision-makers can be said to act rationally when challenged by complex decision-making environments. Evidence relating to demand for information and the impact of feedback on behaviour is provided with two studies: The first uses a simulated auction platform to examine behaviour within overlapping auctions of short duration with close-to-identical items and minimal participation costs. Mouse tracking is used to capture data on relevant interactions of participants with the simulated online platform, including switching behaviour independent of bidding. The resulting data suggests that participants did behave in a manner consistent with utility maximisation, seeking to acquire the item at the lowest possible price and showing no bias in terms of auction preference. The impact of fixed-price offers in the form of a "Buy it Now" option is also examined with some evidence that participants again seek, and respond to, current information when deciding on their bidding strategy. The second study is a test of the impact of real-time feedback and demand for information within the context of financial markets. The study again uses a novel simulated environment which provides access to considerable amounts of relevant data which participants can choose to access. In addition, participants are exposed to regular feedback with regard to their own performance. Overall, demand for information is found to be dependent upon the type of feedback received and its context. Decision-makers then appear to behave objectively, apparently seeking the latest available information to support current decisions, although investor style is found to be important in determining overall trading propensity. The thesis starts by considering a number of the foundations and pathways which run through the judgment and decision-making literature. It is not a complete description, review or analysis of all of the prevailing lines of enquiry. Nevertheless, it seeks to achieve coherence in terms of bringing together some of the key themes dealing with risky choice under conditions of uncertainty and ambiguity. The field of judgment and decision-making is inevitably vast; its scope owing much to the fact that it transcends individual disciplines. The emergent behavioural sciences thus draw together important strands from various sources, notably Economics and Finance. In many areas, psychological traits can be applied to explain inconsistencies which are found in classical theory of rational behaviour. The recognition of behavioural traits has thus contributed greatly to the evolution of decisionmaking theories under conditions of uncertainty and ambiguity which are, in many cases, substantially more adaptable and robust than early normative theories of rational behaviour. The classical approach to rational decision making within Economics, together with some theoretical and empirical challenges to it, are considered in Chapter 1. It is here that we are introduced to the Rational Man. Like the mythical creatures found in Classical Antiquity, the Rational Man does not actually exist in the real world; he is nevertheless central to the concept of utility maximising rational choice which provided much of the foundation of Economics. Developments of expected utility theory (EUT) are considered, including its replacement of expected value, and the formalisation of rational behaviour within the context of axioms. When those logical axioms apply, decision-makers can be said to behave 'as if' they are utility maximises. The chapter ends with some empirical evidence, showing the types of approaches often used to explore rational decision-making. Some violations of EUT are explored, both in relation to notional gambles and consistency with regard to revealed preferences. Chapter 2 extends the narrative by considering rational decision-making in cases where there is no objective information about possible outcomes. Subjective utility theory (SEU) is then introduced, describing objective functions based upon preferences derived from combined utility and probability functions. The implications of the Allais' and Ellsberg paradoxes are discussed, along with some possible solutions. It is here that we explore the concepts of uncertainty and ambiguity in more details and consider some theoretical formulations for addressing them. Chapter 3 covers the significant contribution to decision-making under conditions of uncertainty provided by Prospect Theory and, later, Cumulative Prospect Theory (CPT). Their evolution from the pioneering work of Markowitz is discussed within the context of reference points relative to which outcomes can be evaluated. The significance of stochastic dominance and rank dependence are explored. By this stage, we have examined numerous theories which have fundamentally transformed standard EUT into much more flexible and adaptable frameworks of rational choice. The core concepts of utility maximisation remain yet the initial, strictly concave utility function describing diminishing marginal utility is now substantially replaced by more complex weighted preference functions. From this theoretical base, the process of choice reduction and the application of heuristics in decision-making are considered. We again describe axiomatic behaviour compatible with rational choice. Therefore, decision-makers faced with multiple choices about which there may be little or no objective information about likely outcomes can nevertheless develop rational beliefs and expectations which can then be applied to reduce complex tasks to more manageable proportions. As well as considering these aspects from the point of view of actual choices, we also consider the processes by which decisions are taken. Thus, process tracing methods are introduced into the discussion. The chapter also explicitly considers the role of feedback in decision making. This includes a consideration of Bayesian inference as a process for updating probabilistic expectations subject to new information. From considering theoretical formulations form which we can judge rational behaviour, Chapter 5 looks at evidence for sub-optimal decision-making and bias. Bias with regard to probability assessments are considered along with empirical evidence of bias in relation to intertemporal discounting. Sunk cost bias is also considered as a clear example of irrational behaviour, leading in to a specific discussion about a number of persistent behavioural biases identified within financial markets. As an introduction to later chapters, this also covers the basic theoretical principles of market efficiency and evidence that real markets fail to adhere to those principles in important ways. Chapters 6 and 8 describe the empirical studies with Chapter 7 providing a more detailed introduction to the financial markets experiment, considering aspects of market efficiency, models of behaviour and other empirical evidence.