Wachter et al., 2009, Sequence/sequential learning: learn a number sequence and assessing the reaction time in completing the sequence as fast as the can, Participants get better when sequence is repeated over and over again. Results showed that reward enhanced retention and punishment enhances performance not particularly learning. Brain Imaging showed striatum was activated during the task, with reward this increased activity, with punishment this decreased activity suggesting an opposing effect/encoded differently in the brain. Maybe reward increase dopamine, and punishment causes a dip.