FIGURE 15.1 Let Bygones Be Bygones Areas of the brain (the ventral striatal) are activated when a person feels regret. In this experiment, brain activation correlated with past loss and then unwise choices, with participants repeating behavior that had just failed. Older adults were usually wiser, as evidenced in brain activation as well as actions. However, elders who had been diagnosed as depressed seemed to dwell on past losses. The positivity effect had passed them by.