How do citizens form and update their opinion about political topics? While the literature generally

agrees that new information has to be received and accepted to affect political preferences,

research on the exact mechanism of information acquisition and the condition under

which this process is more or less likely remains scarce. This is what we tackle in this paper by

paying special attention to the active search for information as well as to the source of it. We

designed and pre-registered an experiment that isolates the process of information acquisition

and especially differentiates between outcomes both as change in salience, persuasion and

changes in intended behavior. Importantly, we also take the source of information (experts

vs citizens) into account. While both passive and active encounters with information makes

individuals more knowledgeable about the topic, an active information search makes them

attributing a greater importance, making them more likely to adapt their attitudes and also

become more willing to take action around it. By studying the influence of an active search for

two new topics and by leveraging several countries in our research, we provide a robust basis

for how the process of information acquisition shapes attitudes. Our findings have important

implications for the public opinion formation literature but also for designers of survey experiments

more broadly.