Abstract
Arbitrating between timely choice and extended information gathering is critical for effective decision making. Aberrant information gathering behaviour is thought to be a feature of psychiatric disorders, such as schizophrenia and obsessive-compulsive disorder, but we know little about the underlying neurocognitive control mechanisms. In a double-blind placebo-controlled drug study involving 60 healthy human subjects (30 female), we examined the effects of noradrenaline and dopamine antagonism on information gathering during performance of an information sampling task. We show that modulating noradrenaline function with 40 mg of the beta-blocker propranolol leads to decreased information gathering behaviour. Modulating dopamine function via a single dose of 400 mg amisulpride revealed some effects that were intermediate between those of propranolol and placebo. Using a Bayesian computational model, we show sampling behaviour is best explained by inclusion of a nonlinear urgency signal that promotes commitment to an early decision. Noradrenaline blockade promotes the expression of this decision-related urgency signal during information gathering. We discuss the findings with respect to psychopathological conditions that are linked to aberrant information gathering.
SIGNIFICANCE STATEMENT
Knowing when to stop gathering information and commit to a choice option is non-trivial. This is an important element in arbitrating between information gain and energy conservation. In this double-blind, placebo-controlled drug study, we investigated the role of catecholamines noradrenaline and dopamine on sequential information gathering. We found that blockade of noradrenaline led to a decrease in information gathering. Dopamine blockade showed an intermediate, but non-significant, effect. Using a Bayesian computational model, we show that this noradrenaline effect is driven by an increased decision urgency, a signal that reflects an escalating subjective cost of sampling. The observation that noradrenaline modulates decision urgency suggests new avenues for treating patients that show information gathering deficits.
Footnotes
The authors declare no competing financial interests.
The Wellcome Trust's Cambridge-UCL Mental Health and Neurosciences Network grant (095844/Z/11/Z) supported RJD, TUH and MM. TUH is supported by the Jacobs Foundation. RJD holds a Wellcome Trust Senior Investigator Award (098362/Z/12/Z). MM was also supported by the Biomedical Research Council. PD was supported by the Gatsby Charitable Foundation. The Max Planck UCL Centre is a joint initiative supported by UCL and the Max Planck Society. The Wellcome Trust Centre for Neuroimaging is supported by core funding from the Wellcome Trust (091593/Z/10/Z).
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