  An analysis drawing on Signal Detection Theory suggests that people may fall
for misinformation because they are unable to discern true from false
information (truth insensitivity) or because they tend to accept information
with a particular slant regardless of whether it is true or false (belief
bias). Three preregistered experiments with participants from the United States
and the United Kingdom (N = 961) revealed that (i) truth insensitivity in
responses to (mis)information about COVID-19 vaccines differed as a function of
prior attitudes toward COVID-19 vaccines; (ii) participants exhibited a strong
belief bias favoring attitude-congruent information; (iii) truth insensitivity
and belief bias jointly predicted acceptance of false information about
COVID-19 vaccines, but belief bias was a much stronger predictor; (iv)
cognitive elaboration increased truth sensitivity without reducing belief bias;
and (v) higher levels of confidence in one's beliefs were associated with
greater belief bias. The findings provide insights into why people fall for
misinformation, which is essential for individual-level interventions to reduce
susceptibility to misinformation.
