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Wednesday, June 1, 2022

The ConTraSt database for analysing and comparing empirical studies of consciousness theories

Yaron, I., Melloni, L., Pitts, M. et al.
Nat Hum Behav (2022).


Understanding how consciousness arises from neural activity remains one of the biggest challenges for neuroscience. Numerous theories have been proposed in recent years, each gaining independent empirical support. Currently, there is no comprehensive, quantitative and theory-neutral overview of the field that enables an evaluation of how theoretical frameworks interact with empirical research. We provide a bird’s eye view of studies that interpreted their findings in light of at least one of four leading neuroscientific theories of consciousness (N = 412 experiments), asking how methodological choices of the researchers might affect the final conclusions. We found that supporting a specific theory can be predicted solely from methodological choices, irrespective of findings. Furthermore, most studies interpret their findings post hoc, rather than a priori testing critical predictions of the theories. Our results highlight challenges for the field and provide researchers with an open-access website (https://ContrastDB.tau.ac.il) to further analyse trends in the neuroscience of consciousness.


Several key conclusions can be drawn from our analyses of these 412 experiments: First, the field seems highly skewed towards confirmatory, as opposed to disconfirmatory, evidence which might explain the failure to exclude theories and converge on an accepted, or at least widely favored, account. This effect is relatively stable over time. Second, theory-driven studies, aimed at testing the predictions of the theories, are rather scarce, and even rarer are studies testing more than one theory, or pitting theories against each other – only 7% of the experiments directly compared two or more theories’ predictions. Though there seems to be an increasing number of experiments that test predictions a-priori in recent years, a large number of studies continue to interpret their findings post-hoc in light of the theories. Third, a close
relation was found between methodological choices made by researchers and the theoretical interpretations of their findings. That is, based only on some methodological choices of the researchers (e.g., using report vs. no-report paradigms, or studying content vs. state consciousness), we could predict if the experiment will end up supporting each of the theories.

Editor's note: Consistent with other forms of confirmation bias: the design of the experiment largely determines its result.  Consciousness remains a mystery, and in the eye of the scientific beholder.