Funding for this research was provided by:
Wellcome Trust (Behaviour Change by Design: 206853/Z/17/Z)
Received: 1 April 2019
Accepted: 26 July 2019
First Online: 28 August 2019
Ethics approval and consent to participate
: Approved by the Psychology Research Ethics Committee of the University of Cambridge (Reference Number: PRE.2018.036). All participants provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.