About this time every year, I pluck from my family’s central posting system—the refrigerator door—those precious expressions of their hearts’ desires: their Christmas lists.
Even though I have been told I could easily find their personalized lists on Amazon, I insist on a list on paper as a way forcing some self-editing of their “must haves.” (I also refuse to do the Christmas shopping online. Call me old-fashioned; I like getting away from the computer, getting into the holiday spirit, and especially, finding the surprise that nobody thought to put on their list, but that we all now agree we could not live without.)
If you have offspring, you know that the cost of the items on their wish list scales with their age according to a mysterious power law. But, years ago, my husband and I decided how much we were willing to spend on Christmas, and we have stubbornly stuck to it. That means the kids with pricier preferences get fewer gifts. (It’s ok, they know the rules. Also, they have figured out emperically what the budget is.)
Normally, brain science does not penetrate my grey matter, but two new papers published in Nature Neuroscience got me wondering: In the context our Christmas spending limits, how do the kids decide what they want? And, how good are those decisions?
My daughter's brain. She makes very good decisions. Credit: MSU.
A group a Trinity College Dublin addressed the first issue of how the brain collects information about the environment and, eventually, makes the decision to act. All day long, we make decisions based on a wide range of incomplete or unreliable information that we constantly gather through our senses. Our persistent survival would seem to be pretty good evidence that the human race is good at making the right decision (most of us do not eat poisonous foods, most of us do not accidentally fall off cliffs, etc.).
According to a press release, the prevailing theory is that the “brain allows information from the senses to accumulate,” and waits to make a decision until a “reliable quantity” of data is collected, but, heretofore, the mechanism of how this happens in the brain has been unknown.
The Trinity group used what amounted to a hearing test (as well as a visual version) and asked participants to “decide” when they could they could hear or see the signal. Using scalp-mounted electrodes to monitor brain activity, the researchers were able to correlate precisely the moment at which a “decision” was made with brain activity and where the activity occurred. Using functional magnetic resonance imaging (a flimsy link to materials science, I admit) they found that brain activity corresponds to the input signal, but participants only registered it when the brain activity reached a threshold level. The significance, according to the press release is, “As a result, it was possible to precisely predict both the timing and accuracy of the participant’s decisions simply by monitoring this brain signal. In other words, it was possible to observe the gradual formation of a decision in the participant’s brain activity before that decision was actually reported. “
So, now I know that the stuff on the lists did not appear frivolously: It has been rolling around in those young brains for awhile.
The next question is, how sure are they about what they want? This matters, after all, if I’m only going to spend so much and no more.
The second article in Nature Neuroscience attempts to evaluate how confident we are about our decisions. A team from University College London, according to the press release, has identified the exact region of the brain that calculates the value of our choices and our confidence in those choices. Christmas gifts are a small thing, but, for example, what if I want to have a lot of confidence in how we have decided to invest our retirement savings?
This group studied hungry test subjects and measured their brain activity as they decided which snacks to eat later. Then, they asked participants to place a value on that choice by saying how much they would pay for each snack. Finally, they were asked to evaluate how confident they were that they had chosen the best snack.
The interesting finding is that the region of the brain that is used to assess choices is also active in deciding confidence levels when choosing the best option. According to the press release, “The study … shows that the interaction between this area of the brain and an adjacent area reflects participants’ ability to access and report their level of confidence in their choices.”
The takeaway point, as expressed by one of the researchers in the press release is, “Overall, we think our results provide an initial account both of how people make choices, and also their insight into the decision process.”
So, armed with these insights and my credit card, I’m off to the mall. I am confident I will choose gifts that will have lasting value and meet all of our needs and wants!
Merry Christmas, friends.