Trust in the European Union is strongly related to trust in national political institutions through extrapolation, i.e. cues from national politics. Most evidence for this mechanism, however, is based on surveys using question blocks that present several institutions at once in non-randomized order. We conducted six split-ballot survey experiments in five European countries, asking about trust in national and European Union institutions (a) separately or in the same question block and (b) in different question orders. Our findings demonstrate survey context effects: asking about two institutions within the same question block increases the correlation of reported levels of trust in these institutions. Furthermore, our findings indicate that national primes decrease reported trust in the European Union, providing novel micro-level evidence for extrapolation and cue-taking from national politics in the formation of public opinion about the European Union.