Search

This thesis investigates various deviations from rational beliefs by combining methods from psychology and experimental economics. The first two studies focused on the jumping-to-conclusions bias, where delusional and delusion-prone individuals tend to make decisions based on less data than controls. In an incentivised and adapted "beads task" probability-reasoning paradigm, the effects of delusion-proneness on decisions and on probability ratings were investigated. All participants, but especially more delusion-prone participants, made their decisions too early. Moreover, high delusion-prone participants' probability ratings were less affected by incentives than low delusion-prone participants'. The same paradigm was used to explore an inaccurate, but potentially evolutionarily advantageous, belief: the sexual over-perception bias, where men perceive more sexual interest in women's behaviour than women report or perceive. No evidence was found for men's over-perception of a male character's appeal to women in a belief-updating paradigm, which may reflect conceptual and methodological limitations of previous work on this topic. Perhaps, people deviate from rationality for certain purposes (e.g., evolutionary goals), while also holding an accurate, rational belief. The fourth study examined whether people are, at some level, aware that their optimistic beliefs are inaccurate, by combining two distinct belief-updating paradigms. Participants provided repeated answers to neutral questions and questions about undesirable future outcomes. Participants were equally accurate for neutral items, but were even more optimistic on the second guess for undesirable items, suggesting that optimism involves "real" self-deception. The last study investigated another phenomenon where people may want to avoid undesirable information. Investors are less willing to invest when playing the trust game with another player than when playing a computerised lottery with the same odds of the outcomes, which suggests that observing potential betrayal carries an additional, emotional cost. It was found that beliefs about others' trustworthiness could predict the level of such betrayal aversion.

This thesis investigates individual and interpersonal predictions of future affect and explores their relation to implicit theories of emotion, prediction recall, debiasing, and focalism. Studies 1, 2, and 3 assessed affect predictions to upcoming reasoning tests and academic results, and Studies 4, 5, and 6 concerned predictions for self-identified events. The first study investigated the influence of implicit theories of emotion (ITE; Tamir, John, Srivastava, & Gross, 2007) on impact bias and prediction recall manipulating ITE between participant pairs who predicted and reported their affective reactions to feedback on a test of reasoning skills. Neither impact bias nor recalled predictions were affected by the manipulation. Recalled affect predictions differed from original affect predictions, but were not influenced by experienced affect. Study 2 further investigated the effects of target event timing on impact bias and affect prediction recall. The results showed no differences between individual and interpersonal impact biases across conditions. Again, recalled predictions differed from original predictions, and were not influenced by experienced affect. Study 3 investigated the influence of prior information about impact bias on interpersonal affective forecasting involving real-world exam results. The results demonstrated no differences in predictions due to information, however, significantly less unhappiness was predicted for participants’ friends compared to self-predictions. Study 4 examined the effect of different de-biasing information on affective predictions. The results demonstrated no differences in affective predictions by condition and found that participants’ ITE were not associated to affect predictions. Study 5 examined individual and interpersonal affect predictions using a between-subjects design in place of the within-subjects design. The results demonstrated no differences between the affect predictions made for self and for friends, and ITE were not associated with predictions. Study 6 examined the impact bias in interpersonal affective forecasting and the role of focalism. The results demonstrated distinctions between individual and interpersonal affecting forecasting with individual impact bias for positive reactions for negative events and individual and interpersonal reverse impact bias for calm emotional reactions to positive events. Immune neglect was found not to be associated with predictions. Overall, the studies found evidence for similar individual and interpersonal predictions which are resistant to influence.

This thesis addresses decision mechanisms in foraging situations, using laboratory experiments with European starlings (Sturnus vulgaris). Building on previous work from the Behavioural Ecology Research Group, I chose the Sequential Choice Model (SCM; reviewed in Kacelnik et al., 2011 − Appendix 1) as a starting point, and tested its premises and predictions generalising it to different experimental protocols. Classical decision models do not relate choice preferences to behaviour towards isolated options, and assume that choices involve time-consuming evaluations of all alternatives. However, previous work found that starlings’ responses to isolated options predict preference in choices, and that response times to single-option encounters are not reliably longer than response times in choices. Since, in the wild, options are normally encountered sequentially, dealing with isolated options can be considered of greater biological, and possibly psychological, significance than simultaneous decisions. Following this rationale, the SCM postulates that when multiple simultaneous stimuli are met they are processed in parallel, each competing against the memory of background opportunities, rather than comparing present options to each other. At the time of launching this research, these ideas had only been applied to protocols involving just two deterministic alternatives and offering no chance to explore the influence of learning history (i.e., how animals learn to choose; see Chapter 4). To increase their relevance and offer more rigorous tests, I generalised them to situations with multiple (see Chapters 2, 4 and 5), and in some cases probabilistic alternatives (see Chapter 3), controlling the learning regime. I combined these extensions with tests of economic rationality (see Chapter 6), a concept that is presently facing sustained debates. Integrating the result of all experimental chapters (see Chapter 7), my results support the notion that behaviour in single-option encounters is fundamental to understand choice behaviour. The important issue of whether choices involve a decision time cost or the opposite, a shortening of response times, remains unsolved, as neither could be evidenced reliably.

This thesis aims to investigate the secondary transfer effect of contact, a phenomenon whereby contact with one outgroup leads to improved attitudes towards other, non-contacted outgroups. While evidence mounts for the existence of secondary transfer effects, its underlying mediation processes remain poorly conceptualised and thus, poorly understood. Thus, in this thesis, I aimed to clarify the conditions under and the processes by which the secondary transfer effect works. Chapter 1 introduces intergroup contact theory and traces its development from the contact hypothesis (Allport, 1954) to the uncovering of the secondary transfer effect. Based on theory from all aspects of intergroup contact research, Chapter 1 proposes a theoretically reformulated approach to understanding the deprovincialization hypothesis by way of (1) diversity beliefs, (2) the development of a multicultural outlook on intergroup relations, and (3) a more nuanced understanding of when ingroup identity is likely to relate ethnocentrically to outgroup attitudes. Point three more specifically looks at the role of social dominance orientation as a moderator of the relationship between ingroup identification and outgroup attitude. Chapter 1 also provides an extension to the attitude generalization hypothesis by considering the role that similarity gradients play. Chapter 2 discusses methodological considerations important to the analysis strategy used throughout the thesis. Six empirical investigations across three contexts—England (Studies 1 and 2), Northern Ireland (Studies 3 and 4) and South Africa (Studies 5 and 6) set out to test the secondary transfer effect and the hypotheses offered in Chapter 1. Across three cross-sectional studies (Studies 1, 2, 3, and 4), a three-wave longitudinal study (Study 5) and an experimental study (Study 6), I was able to show the following: (a) that attitude generalization is a robust mediator of the secondary transfer effect (Studies 1, 2, 3, 4, and 5); (b) similarity gradients qualify the attitude generalization process such that attitudes generalize more strongly between outgroups that are perceived to be similar (Studies 3, 4, and 5); (c) that diversity beliefs (Study 2) and multiculturalism (Study 4), as alternative interpretations of the deprovincialization effect, mediate the secondary transfer effect; (d) social dominance orientation moderates the relationship between ingroup identification and outgroup attitude (Study 3); (e) that the deprovincialization and attitude generalization hypotheses are not independent, but rather interrelated processes of the secondary transfer effect (Studies 2, 3, and 4); (f) that experimentally manipulated forms of extended contact can lead to the secondary transfer effect because group categories and membership are made salient during the extended contact experience (Study 6); and (g) that it is contact that leads to wider attitude generalization rather than less prejudiced people seeking contact from a wider pool of social groups (Study 5). Furthermore, owing to their three-wave longitudinal (Study 5) and experimental (Study 6) designs, these two studies provide the most convincing evidence of the causal nature—from contact to reduced prejudice—of the secondary transfer effect to date. Taken together, these six studies provide a wealth of critical support for the secondary transfer effect as well as for the reformulated deprovincialization and the extended attitude generalization hypotheses.