Experimental design and tasks.

<p>(A) tDCS conditions and tasks were independently randomly ordered across participants. Encoding and recognition, as well as tDCS conditions were separated by ∼72 hours to test long-term recognition and avoid cross-over cortical excitability modulation effects. (B) Example of one encoding task block. Encoding tasks consisted of three blocks, each comprising 15 different unfamiliar faces presented 15 times consecutively. (C) Example of a corresponding recognition task. The 45 unfamiliar faces encoded ∼72 hours earlier are presented amongst 45 novel faces. For each face, participants responded either "known" or "unknown" (here, correct answers are indicated on the intertrial interval). Stimuli in this figure are not the originals, but similar stimuli used for illustrative purposes only.