Funding for this research was provided by:
Directorate for Computer and Information Science and Engineering (1452854)
Directorate for Social, Behavioral and Economic Sciences (1449351)
Received: 10 August 2016
Accepted: 7 March 2017
First Online: 28 March 2017
Compliance with Ethical Standards
: Shilton has received research grants from Google. Google has not approved or influenced the results of this study.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.