Sequence of trial events in (A) learning and (B) generalization phases. Each trial began with the presentation of a fixation cross at the center of the screen for a random duration between 400 and 600 msec. A colored word then appeared around the center location for 1000 msec or until the participant reported the color of the word, followed by a 1000-msec blank screen. We used a trial-to-trial spatial uncertainty of 100 pixels around the center location (to present words) in order to limit opportunities for using strategies (e.g., fixating on a small portion of the print to avoid reading words; Ben-Haim et al. 2014). In the learning phase, correct responses resulted in the delivery of monetary reward feedback (displayed for 1500 msec) including the amount of reward earned on the current trial (10¢, 2¢, or 0¢ for high, low, or no reward, respectively), as well as the total accumulated reward. Next, a 1000-msec blank screen was presented before the start of a new trial. Participants did not receive a reward in the generalization phase. In each phase, for incorrect responses and misses, a 1500-msec feedback display indicated “incorrect” or “miss,” respectively, at the center location just after the presentation of the word, and a 1000-msec blank screen appeared before the next trial. Throughout the experiment, the background of the screen was dark gray while the fixation cross and feedback appeared in white. Written information was presented in 60-point Arial font.
