While we might wish to find the perfect life companion -- Mr. or Ms. "Right" -- evolution has shaped us to survive by settling for Mr. or Miss "OK," scientists say.
That evolutionary strategy goes back to early humans who found that when the survival stakes were high -- and nothing was more important than successfully finding a mate -- it was best to practice risk aversion, meaning they were better off settling.
"Primitive humans were likely forced to bet on whether or not they could find a better mate," says Chris Adami, a professor of molecular genetics and microbiology at Michigan State University. "They could either choose to mate with the first, potentially inferior, companion and risk inferior offspring, or they could wait for Mr. or Ms. Perfect to come around.
"If they choose to wait, they risk never mating," he says in explaining why settling for the early sure bet rather than waiting for perfection was an evolutionary advantage.
For their study on the evolution of risk aversion, Adami along with his MSU research colleague Arend Hintze utilized a computer model with digital organisms to follow risk-taking behaviors through thousands of evolutionary generations.
Their digital organisms were programmed to make or reject bets on the life-altering decisions that face all natural organisms, such as choosing another individual to mate with.
"An individual might hold out to find the perfect mate but run the risk of coming up empty and leaving no progeny," Adami said.
How much we're willing to bet on finding the perfect mate -- and whether we're willing to take that risk -- is strongly linked to the size of the immediate group we're raised in, the researchers found.
If they created a group of their digital organisms smaller than about 150 individuals, they proved much more risk averse than in large digital communities, they discovered.
Since primitive humans tended to live in small groups of similar size, it was natural for them to avoid risk by settling for a first mate rather than a perfect one, they say.
"We found that it is really the group size, not the total population size, which matters in the evolution of risk aversion," Hintze says.
So why will some people buck the trend and hold out for the perfect mate -- even with the evolutionary and survival risk that entails?
"We do not all evolve to be the same," Adami says. "Evolution creates a diversity in our acceptance of risk, so you see some people who are more likely to take bigger risks than others. We see the same phenomenon in our simulations."