During twelve 80-trial blocks (960 trials total), participants listened to a series of either tones or syllables (6 blocks each) consisting of 20% target and 80% nontarget stimuli (fixed 2,000 ms SOA). The assignment of target and nontarget stimulus was systematically alternated in two consecutive blocks (A4 vs. B4, /da/ vs. /ta/). Participants were instructed to respond to infrequent target stimuli as quickly and accurately as possible using one of three response modes: 1) a right-hand button press (R); 2) a left-hand button press (L); or 3) by silently counting (S) the targets (participants reported their target count at the end of the block). These response modes were systematically crossed with task type (T, P), and assignment order was counterbalanced across participants (e.g., PL-TL-PR-TR-PS-TS or TL-PL-TS-PS-TR-PR). To reduce ocular artifacts, participants were instructed to fixate a cross on a monitor while listening to the stimuli.
