Are you a risk taker? Or, are you a risk averter? According to a recent article in the New York Times (Rats That Tend to Gamble Help Reveal Science of Risk by Pam Belluck, March 24, 2016 at page A21), the answer lies in a specific type of neuron or nerve cell in the brain. That is, you are hard wired to love risk or to hate it. But, modern science can also manipulate that neuron to turn the risk taker into a risk avoider.
In a study conducted on rats by Dr. Karl Deisseroth, a Stanford neuroscientist and psychiatrist, and his colleagues, they found that a risk adverse rat made decisions based on the outcome of its previous choice; that is, whether there was a gain or a loss (involving food). If the rat lost food in the last round, it acted more conservatively in the next round. The researchers saw this behavior in the rat’s brain, and specifically by signals from certain receptors in the nucleus accumbens region of the brain. (Id.) “These receptors, which are proteins attached to neurons, are part of the dopamine system, a neurochemical important to emotion, movement and thinking.” (Id.)
In those rats that love to take risks, these receptors “…sent a much fainter signal, so the rats kept making high-stakes choices even if they lost out.” (Id.) Interestingly though, when the researchers used optogenetics, or a technique that uses light to manipulate neurons, they were able to stimulate the brain cells of these high risk taking rats to strengthen the “loss” signal and thus turn these rats into more conservative risk averters.
The experiments used involved pulling levers for food:
Step by step, the researchers built evidence that neurons with a dopamine receptor called D2 in the nucleus accumbens, a region integral to brain reward circuitry, play a critical role in risky-or-not decision-making. Strikingly, they found they could alter the message those neurons send.
Rats were given a choice of two food levers. One released a consistent amount of sucrose each time; the other often delivered a tiny amount, but in 25 percent of presses, it unleashed a delicious sucrose flood. Over time, both levers gave the same quantity, so rats did not go hungry and their choices came down to whether or not they were gamblers.
Risky rats gambled on the iffier lever more than half the time. Risk-averse rats were strongly influenced by their last choice; if they picked the risky lever and received a trickle, they picked the consistent lever next time.
”Some are very sensitive to losing, and if they take a risky option and lose, they’re very likely to not go back to it again,” said Paul Phillips, a professor of psychiatry and pharmacology at the University of Washington and a co-author of a commentary about the study. “That’s very common in human behavior. An analogy is a slot machine in Vegas.” (Id.)
Using optogenetics, on the risky rats;
… the team stimulated nucleus accumbens neurons with D2 receptors at the very moment of the fateful food-lever decision. That caused the receptors to send strong loss signals to the rats, apparently making them weigh recent losses more heavily, and prompting them to play it safe with their next lever choice.
“It turns out you can explain a large part of whether rats were risky or not by this particular signal at this particular time,” Dr. Deisseroth said. “We saw it happen, and then we were able to provide that signal, and then see that we could drive the behavior causally.” (Id.)
So, how does this relate to humans? While Dr. Deisseroth recognizes that opotogenetic manipulation on humans is too invasive, at the same time, he points out that it has valuable lessons for humans. Whether we love or avoid risk is rooted in our biological makeup. It is in our DNA.
As the Doctor notes, knowing this, perhaps we can be more tolerant and understanding of other people and why they make the decisions they do. This may well come in handy the next time you are in a dispute with someone: She is taking or avoiding a risk (and thereby making a decision) based on a chemical reaction in her brain. It is nothing more complicated than that.
…. Just something to think about.