The maximum number of pumps possible was set to 128 for each balloon with an explosion a priori equally likely to occur on any given pump subject to the constraint that within each sequence of ten balloons the average explosion point was on pump 64. All participants were presented the same balloons in the same order to limit extraneous variability. A balloon that did not explode was encoded as a “positive feedback” trial; a balloon that exploded was encoded as a “negative feedback” trial. The two types of feedback were used for analyses of FRN and P300 activity during completion of the BART.
