A peer-reviewed study conducted by a trio of Princeton and NYU political scientists and published in Science Advances systematically examined the proliferation of fake news in the 2016 election cycle and found that, contrary to earlier reports, disinformation did not get shared very widely, and that most of it was right-wing, and that the people who shared disinformation of all political orientation were over 65.
Users over 65 were seven times more likely to share hoaxes than users aged 18-29, but the vast majority of users never shared hoaxes, and not because they weren't sharing anything — they simply did not share disinformation.
Within this cohort, lower levels of digital literacy could be compounded by the tendency to use social endorsements as credibility cues (19). If true, this would imply a growing impact as more Americans from older age groups join online social communities. A second possibility, drawn from cognitive and social psychology, suggests a general effect of aging on memory. Under this account, memory deteriorates with age in a way that particularly undermines resistance to "illusions of truth" and other effects related to belief persistence and the availability heuristic, especially in relation to source cues (20–22). The severity of these effects would theoretically increase with the complexity of the information environment and the prevalence of misinformation.
We cannot definitively rule out the possibility that there is an omitted variable biasing our estimates, although we have included controls for many individual-level characteristics theoretically related to acceptance of misinformation and willingness to share content online. Even if our models are correctly specified, we use observational data that cannot provide causal evidence on the determinants of fake news sharing. This study takes advantage of a novel and powerful new dataset combining survey responses and digital trace data that overcomes well-known biases in sample selection and self-reports of online behavior (8, 9). However, we are still limited in our ability to collect these data unobtrusively. Despite our high response rate, half of our respondents with Facebook accounts opted not to share their profile data with us. Any inferences are therefore limited insofar as the likelihood of sharing data is correlated with other characteristics of interest.
Less than you think: Prevalence and predictors of fake news dissemination on Facebook [Andrew Guess, Jonathan Nagler and Joshua Tucker/Science Advances]
People older than 65 share the most fake news, a new study finds [Casey Newton/The Verge]