(A) Example trial sequence. On each trial, one of four different colored robots appeared on the screen (750 ms). Then a fixation cross was shown (250 ms), followed by the robot's “button” (1500 ms). For “Go” responses, the border of the button appeared bold for the remainder of the 1500 ms. When the button disappeared, an outcome appeared on the screen (1000 ms). Each trial was followed by a fixation intertrial interval (750 ms). (B) Each robot was associated with the potential to either win or lose a ticket. Greater Pavlovian bias is reflected in a heightened tendency to take action in anticipation of reward or withhold action in anticipation of punishment (bolded diagonal). (C) Reward contingencies across conditions. In the controllable condition, a correct action for a given robot resulted in the desirable outcome 80% of the time (a ticket for Ticket Givers and nothing for Ticket Takers), whereas in the uncontrollable condition, outcomes were not contingent upon participant's actions.
