Neural representations of social and non-social uncertainty in human decision making

The social landscape is filled with an intricate web of species-specific desired objects and course of actions. Humans are highly social animals and, as they navigate this landscape, they need to produce adapted decision-making behaviour. Traditionally social and non-social neural mechanisms affecting choice have been investigated using different approaches. Recently, in an effort to unite these findings, two main theories have been proposed to explain how the brain might encode social and non-social motivational decision-making: the extended common currency and the social valuation specific schema (Ruff & Fehr 2014). One way to test these theories is to directly compare neural activity related to social and non-social decision outcomes within the same experimental setting. Here we address this issue by focusing on the neural substrates of social and non-social forms of uncertainty. Using functional magnetic resonance imaging (fMRI) we directly compared the neural representations of reward and risk prediction and errors (RePE and RiPE) in social and non- social situations using gambling games. We used a trust betting game to vary uncertainty along a social dimension (trustworthiness), and a card game (Preuschoff et al. 2006) to vary uncertainty along a non-social dimension (pure risk). The trust game was designed to maintain the same structure of the card game. In a first study, we exposed a divide between subcortical and cortical regions when comparing the way these regions process social and non-social forms of uncertainty during outcome anticipation. Activity in subcortical regions reflected social and non-social RePE, while activity in cortical regions correlated with social RePE and non-social RiPE. The second study focused on outcome delivery and integrated the concept of RiPE in non-social settings with that of fairness and monetary utility maximisation in social settings. In particular these results corroborate recent models of anterior insula function (Singer et al. 2009; Seth 2013), and expose a possible neural mechanism that weights fairness and uncertainty but not monetary utility. The third study focused on functionally defined regions of the early visual cortex (V1) showing how activity in these areas, traditionally considered only visual, might reflect motivational prediction errors in addition to known perceptual prediction mechanisms (den Ouden et al 2012). On the whole, while our results do not support unilaterally one or the other theory modeling the underlying neural dynamics of social and non-social forms of decision making, they provide a working framework where both general mechanisms might coexist.

Volunteering for the Commonwealth Games: what can realist synthesis contribute to health policy making?

The aim of this thesis was to investigate, using the real-time test case of the 2014 Commonwealth Games, whether the realist synthesis methodology could contribute to the making of health policy in a meaningful way. This was done by looking at two distinct research questions: first, whether realist synthesis could contribute new insights to the health policymaking process, and second, whether the 2014 Commonwealth Games volunteer programme was likely to have any significant, measurable, impact on health inequalities experienced by large sections of the host population. The 2014 Commonwealth Games legacy laid out ambitious plans for the event, in which it was anticipated that it would provide explicit opportunities to impact positively on health inequalities. By using realist synthesis to unpick the theories underpinning the volunteer programme, the review identifies the population subgroups for whom the programme was likely to be successful, how this could be achieved and in what contexts. In answer to the first research question, the review found that while realist methods were able to provide a more nuanced exposition of the impacts of the Games volunteer programme on health inequalities than previous traditional reviews had been able to provide, there were several drawbacks to using the method. It was found to be resource-intensive and complex, encouraging the exploration of a much wider set of literatures at the expense of an in-depth grasp of the complexities of those literatures. In answer to the second research question, the review found that the Games were, if anything, likely to exacerbate health inequalities because the programme was designed in such a way that individuals recruited to it were most likely to be those in least need of the additional mental and physical health benefits that Games volunteering was designed to provide. The following thesis details the approach taken to investigate both the realist approach to evidence synthesis and the likelihood that the 2014 Games volunteer programme would yield the expected results.