Living organisms, from viruses to vertebrates, have evolved to maximize their chances of survival, biologists tell us. Natural selection includes a form of bet-hedging, where organisms produce a diversity of traits, including some that are even disadvantageous in the short term, as a way to guarantee survival in an unexpected environment. Yet, a new study finds people don’t always follow this trusty evolutionary course of hedging their bets.

When it seems difficult to find a romantic partner, we humans are more likely to go for broke. The University of Michigan researchers behind the study say this pattern may not actually contradict evolutionary wisdom. Given the option of doing whatever it takes to find a romantic partner or risk staying alone, taking radical action may be the more rational choice.

Gambling Odds

Faced with uncertainty, we humans tend to spread our resources among the available options to maximize potential for a win. Echoes of this resound throughout the financial world, where investment advisors routinely recommend diversifying investments instead of relying on just one and hedge funds attempt to maximize returns by using more than one strategy.

Yet, playing the odds may not be the optimal strategy when romantic success is on the gambling table, hypothesized Dr. Joshua M. Ackerman, lead author of the study, and his colleagues. To test this theory, the researchers designed a series of studies that included manipulating participants’ belief in their ability to find a partner.

The first study involved 93 heterosexual participants (53 men, average age of 32). Believing themselves to be enrolled in a memory study, participants looked at three photos of young men and women who supposedly lived in the local community. An imbalanced ratio of men to women appeared in each snapshot with up to 14 more women (or men) appearing in each snapshot. Later they were asked to recall the number of men and women in the photos. The psychologists say this exercise planted a suggestion that the sex ratio was not working in their favor when it came to romance. Believing more single men than single women lived in an area, a straight guy might assume he had worse, not better chances of finding a girlfriend.

Next, for an ostensibly unrelated task, participants had to choose between buying one $10 scratch-off lottery ticket for a $10,000 prize or 10 tickets costing $1 and paying $1000 each for the win.

Who chose what? Participants who previously had seen an unfavorable sex ratio were more likely to buy the riskier $10 ticket than those who saw a favorable ratio. Instead of hedging their bets, these hapless souls decided to go for broke.

“Interestingly, we did not find consistent differences between women and men across our studies,” Ackerman told Medical Daily in an email. Though it might be expected men would care more about money for the purpose of attracting women, the findings suggest both sexes think alike when the dating odds work against them. “This could mean that women see themselves as more attractive (or more likely to out-compete other women) by acquiring money, or it could be a more general pattern of decision making people use.” Even with non-monetary items, people might have shown the same pattern of choices.

In a second study, 105 participants read a newspaper article discussing demographic trends and then evaluated and chose stock packages. Once again, men and woman who first read about unfavorable sex ratios tended to select high-risk, high-return investments. Two additional studies showed similar outcomes: sex ratios influenced decisions indirectly linked with mating success.

The results suggest sexual competition motivates us to attempt to achieve the largest possible reward, regardless of the risk, Ackerman and his colleagues say. Being psychologists and not economists, they haven't yet examined the larger trends across time.

“We might expect that across cultures or areas where the sex ratio is skewed (e.g., in the U.S., there are generally more women than men on the East Coast and more men than women on the West Coast), that people facing unfavorable ratios engage in more high risk/high reward decision making,” said Ackerman. A word to the wise: check the sex ratio before moving to a new town.

Source: Ackerman JM, Maner JK, Carpenter SM. Going All In: Unfavorable Sex Ratios Attenuate Choice Diversification. Psychological Science.2016.