Participants were studied over 3 consecutive days (see Figure 1). On Day 1, all participants underwent partial discrimination fear conditioning, in which they were presented with two neutral visual conditioned stimuli on a computer screen (CS+s; e.g., blue and yellow squares) that co-terminated with an aversive white noise burst US through a pair of headphones (500 ms, 100dB; (Dunsmoor et al., 2008)) at a partial reinforcement rate of 35%. Fear acquisition consisted of 15 non-reinforced presentations of each of the CSs, intermixed with an additional 8 presentations of each CS+ that co-terminated with the US. A third CS (e.g. red square) was presented during fear conditioning but never paired with the US (CS−; adapted from (Schiller et al., 2010)).
