We will study metacognition and using and weighing ability through theoretical and experimental work.

Philosophy-led research will develop a theoretical framework that connects the legal test of ‘use and weigh’ and metacognition. For example, it will entail analysis of how rationality requires account of other peoples’ judgements (but not just agreeing with consensus) and ‘social epistemology’(35).

Experimental work will start with healthy volunteers moving on to people with conditions such as early dementia, brain injury, mood disorders and psychosis.

We will use tasks pioneered by Fleming which measure confidence in decisions at a given level of accuracy. This measure (“meta-d’”) has a specific neural instantiation and we will apply paradigms (adjusted for difficulty) to enable comparison between healthy and clinical groups. The work will quantify disorder-related deficits and examine whether these are common across disorders or disorder-specific.

There are three important aspects of metacognition which underlie ‘use and weigh’: (i) the mapping of values/desires onto decision-making; (ii) the construction of beliefs about the decision process; (iii) integration of social feedback. To operationalise (i), we will test for violations of utility theory; for (ii) we will employ decision and confidence tasks, and to examine (iii) we will design a bespoke extension (incorporating social feedback) to the metacognitive measure.

To deepen links between neuroscience and DMC we will also explore other paradigms with collaborators including neuroeconomic, moral reasoning and mood-manipulation paradigms. We will also devise novel ecologically valid methods of testing real-world decision-making using dialogic methods and large-scale internet surveys.

Finally, we will correlate metacognitive parameters (eg.,meta-d’) with clinical measures including insight, self-reflection and self-certainty scales, ‘theory of mind’ reasoning and executive functioning.

All experimental approaches will be refined in the light of our theoretical work and informed by the functional test of DMC.

We will innovate interdisciplinary working in mental health, cognitive neuroscience and law and pave the way for future functional imaging and neurocomputational studies. The work-stream will also provide a practical synthesis of clinical measures relevant to assessment of DMC. These will be generalised enough so as to be useful to clinicians across a number of real-life settings yet informed by the work of Work Stream 4. To demonstrate the importance of metacognition for DMC in an accessible way for the public, we will produce web-based, interactive demonstrations - including YouTube videos, animations, online tests and ‘games’.