  Scepticism towards childhood vaccines and genetically modified food has grown
despite scientific evidence of their safety. Beliefs about scientific issues
are difficult to change because they are entrenched within many related moral
concerns and beliefs about what others think. We propose a cognitive network
model which estimates the relationships, dissonance, and randomness between all
related beliefs to derive predictions of the circumstances under which beliefs
change. Using a probabilistic nationally representative longitudinal study, we
found support for our model's predictions: Randomness of the belief networks
decreased over time, for many participants their estimated dissonance related
positively to their self-reported dissonance, and individuals who had high
estimated dissonance of their belief network were more likely to change their
beliefs to reduce this dissonance. This study is the first to combine a
unifying predictive model with an experimental intervention and sheds light on
dynamics of dissonance reduction leading to belief change.
