Аннотация:The project examined behavioral and electrophysiological brain responses to auditory deepfakes that were created for two well-known speakers and investigated participants with pro-vaccination and anti-vaccination attitudes. Our analysis focused on EEG activity taking into account congruence or incongruence of internal attitudes and the degree of analytical thinking, need for cognition and conformity of participants. We found that the level of trust to deepfakes was significantly influenced by the interaction between internal attitudes and speaker and need for cognition. The higher negative evoked brain response, alike to the N600 component, was observed for anti-vaccination group in mismatch to public opinion of the speaker.