  Struggling to curb misinformation, social media platforms are experimenting
with design interventions to enhance consumption of credible news on their
platforms. Some of these interventions, such as the use of warning messages,
are examples of nudges -- a choice-preserving technique to steer behavior.
Despite their application, we do not know whether nudges could steer people
into making conscious news credibility judgments online and if they do, under
what constraints. To answer, we combine nudge techniques with heuristic based
information processing to design NudgeCred -- a browser extension for Twitter.
NudgeCred directs users' attention to two design cues: authority of a source
and other users' collective opinion on a report by activating three design
nudges -- Reliable, Questionable, and Unreliable, each denoting particular
levels of credibility for news tweets. In a controlled experiment, we found
that NudgeCred significantly helped users (n=430) distinguish news tweets'
credibility, unrestricted by three behavioral confounds -- political ideology,
political cynicism, and media skepticism. A five-day field deployment with
twelve participants revealed that NudgeCred improved their recognition of news
items and attention towards all of our nudges, particularly towards
Questionable. Among other considerations, participants proposed that designers
should incorporate heuristics that users' would trust. Our work informs
nudge-based system design approaches for online media.
