Publications

Consciousness is an ethically loaded term. Learning that someone is conscious changes our beliefs not only about what it is like to be them, but also about how we should and shouldn’t treat them. In this paper, we identified 3 implications of this link between consciousness and ethics. First, empirical findings in this field should inform ethics and legislation. For example, if we identify markers of consciousness in an animal, this should affect how we treat this animal. Second, because of this link, consciousness scientists are particularly susceptible to influences from ideology and societal norms. This is because we prefer theories of consciousness that align with our prior intuitions about who is conscious and who is not, but these intuitions are biased by our moral outlook and lifestyle. And finally, this link also means that the use of animal models of consciousness produces a conflict between scientific validity and ethical justification.

When participants report being aware of a stimulus, specific regions in their prefrontal and parietal cortices are activated. In this project we asked whether this brain activity was correlated with subjective visibility or alternatively with decision confidence. Together with Nadine and Steve we explored an existing dataset and found that many of the brain activations that are commonly associated with visual awareness disappear when controlling for decision confidence.

Some searches are really easy - the thing you are looking for just pops out to your attention. Interestingly, the same kind of searches also trigger an immediate perception of the absence of a target when it is not there. In this project we investigated this phenomenon of absence pop-out and found that it is independent of task experience and explicit metacognitive knowledge about search efficiency.

In detection tasks, people are slower, less confident, and less able to identify their own errors in reporting stimulus absence than presence. We thought this might be related to a more general difficulty in making inference based on the absence of evidence, a bit like interpreting p>0.05 in statistical testing. Together with Steve and Rani, we tested this idea in a Registered Report. Our findings suggest that presence/absence asymmetries in overall confidence and RT are indeed most likely to reflect a general difficulty in interpreting absence of evidence, but that asymmetries in metacognitive sensitivity are more specific to visual nothingness.

Together with my PhD supervisors Karl and Steve, we used functional MRI to ask whether brain regions that contribute to our confidence in what we see also contribute to confidence in whether we see something at all. This is the first imaging study from my PhD, and it is also the first ever pre-registered neuroimaging study to come out of the Wellcome Centre for Human Neuroimaging. We found that the same brain regions were involved in the two types of confidence, with some unexpected differences in the translation of brain activity to subjective confidence. In a second, pre-registered replication study, most of these unexpected differences were not replicated.

Working on my Master’s thesis, I got frustrated with how easy it was to get significant results out of pure noise by overfitting the analysis plan to the data. Standard pre-registration seemed like an unsatisfying solution - if we don’t trust researchers to honestly report their original analysis plans, why should we trust them that they have pre-registered their analysis plans before data collection, and not after it? Together with my brother Noam, we invented and implemented a mechanism that prevents this sort of cheating by encoding the registration plan in experimental randomization.