There are many situations where taking a risk pays off, whether we think of stealth military operations, chancy shots in the final seconds of a basketball game, or significant investments in an up and coming stock option. Playing it safe pays off. But those who stick their necks out and take a chance, may bring home significant gains. It is because of these competing strategies and potential payoffs that evolutionary biologists have imagined that selection could maintain both personality types within a population — a point noted earlier for the MAOA and glucose-related genes. If selection has worked in this way, then there must be genetic variation that allows for both strategies. To date, the strongest evidence comes from a family of genes associated with the regulation of dopamine, with the memorable acronyms of DAT1, DRD2 and DRD4; each of these genes is associated with different forms, each form associated with different levels of dopamine. Recall from chapter 2 that dopamine plays an essential role in our experience of reward, including how motivated we are to get it and what we anticipate based on our understanding of the situation — have we been rewarded in the past, how often, and how much? The idea here is that those who carry genes that output a higher level of dopamine may weight rewards more heavily and thus, show risk-blindness; for these individuals, the eye is on the prize, not the path or obstacles to this prize. Across a number of studies, results show that variation in the expression of these genes is associated with high-risk, low self-control behaviors, including pathological gambling, substance abuse, sensation seeking, and financial investments. For example, in two separate studies, individuals with different variants of the DRD4 gene played a financial investment game involving real money. In one, designed by Joan Chiao, subjects decided to invest in either a risky asset with variable returns or a riskless asset with consistent returns. In th