There are certain foods and drinks that most people would consider empty calories, such as sodas and many kinds of snacks. When we eat or drink them, we feel nourished, when in reality we’re still lacking the ingredients needed to sustain a healthy organism. Many forms of information are like empty calories—a lot of the news we receive, for example. The mind works at taking in facts and comprehending events. It feels like we’re learning, but the ingredients of deep knowledge are missing.
I recently read a BBC news item with the headline: “Brain’s adventure centre located.” Using functional magnetic resonance imaging (fMRI) to see which part of the brain received the most blood flow—presumably indicating that this particular part of the brain is working harder than the rest—researchers at the University College London asked volunteers to select from several familiar images. Each image carried a reward, and the volunteers could learn the rules for achieving the most rewards. But when the researchers added unfamiliar images to the mix, the volunteers would take a chance on them. At the moment they chose to take a risk for an unknown reward, the ventral striatum received more blood flow. The conclusion was that this area of the brain controls the cognitive process for seeking new experiences.
Whenever I hear that someone has discovered a new center in the brain, a warning light goes on in the part of my brain where I do my logical thinking. The idea that a given function or behavior is produced by a specific part of the brain has a long history. In the early 1800s, a neuroanatomist named Franz Joseph Gall tried to categorize parts of the brain by, among other things, measuring the bumps on people’s heads. While phrenology never yielded any useful scientific information, it did promote the idea that it would be good to learn what each part of the brain did, just as you might study the components of an automobile to see what made it run.
Then in the 1950s two young scientists at McGill University, James Olds and Peter Milner, found that if they electrically stimulated a part of a rat’s brain known as the nucleus accumbens, the animal would feel pleasure. They rigged up a lever that rats could press to receive stimulation. The rats would ignore food, water, and even sex while pressing the lever over and over like crazed gamblers at a slot machine. They would do that until they died of exhaustion. Olds wrote a popular account of the study in Scientific American in 1956. The editors gave it the cute title “Pleasure Centers in the Brain,” and it stuck. There was something deeply appealing about the idea that the brain is a bunch of components, each with a specific function. People thought of it as operating like a telephone exchange, sending and receiving signals to keep things running smoothly. Unfortunately, saying you’ve discovered the pleasure center in the brain is a little like saying that your right foot is the speed center of your car.
And that’s where the analogy between brain and machine ends. Because you can’t cut a car in half and have a smaller car. But you can lose an awful lot of brain material and still have a brain that functions pretty well. It is true that damage to specific areas of the brain will reliably result in characteristic deficits. If you destroy the visual cortex, you’ll be blind. But the brain functions much more globally than popular accounts would suggest. As one neuroscientist told me, “Everything is connected to everything else.” And everything is talking to everything else. Indeed, neuroscientists are increasingly coming to realize that discussing the brain without taking into consideration the rest of the body leaves too much out of the story of how we behave the way we do. After all, the brain sends extensions of itself to every part of the body in the form of nerve fibers.
I’m sure that the ventral striatum must have had something to do with what was going on in a volunteer’s brain when he or she chose to try a new image. And research like this is valuable, as scientists discover small pieces of the great puzzle of how the brain helps shape our behavior. But an unintended consequence of this type of research is that popular news outlets perpetuate a simpleminded view of a very complex topic. The BBC headline suggests that a great quest was on and now it’s over. But even if the ventral striatum is the adventure center, naming it doesn’t tell us how it works. It feels like we understand something, but we really haven’t learned much. It’s like empty calories. If you know that you’re ignorant of something, you’ll be motivated to learn. If you think you know something when you don’t, that motivation isn’t there.
Being interested in whatever is new and unknown has an undeniable evolutionary logic to it. In mammalian creatures like ourselves, the drive to investigate everything is powerful enough to kill us. That’s why parents have to care for their young to moderate that drive and teach them what’s dangerous. This novelty system, if you will, has two main components. One drives us to explore and seek out novelty for its own sake. The other is a stereotyped pattern of responses when something new enters our sensory field.
If you’re trapped on the third floor of a burning building, you are not likely to begin seeking novelty. You’ll be attempting to return to a state of equilibrium where not much is happening. However, if you’re just sitting in your office filling out spreadsheets, you may well be dreaming about a mountain biking trip or a hike in the woods. Indeed, there appears to be a level of risk that each of us likes. Some people like a good book, others like to jump out of airplanes. If we perceive our environment as being too safe, we take more risks. If it seems too hazardous, we take fewer risks. This theory, known as risk homeostasis, can be seen in all sorts of activities.
- Nat Geo Expeditions
When antilock brakes were first being tested, it was thought that the accident rate would go down. Instead, it went up slightly. In a controlled experiment, the German Ministry of Transport found that taxi drivers who knew that they had antilock brakes drove more aggressively. After a time, the accident rate returned to normal. But it is through this system of taking a measured amount of risk that we discover what is in our world that can help or harm us.
When something novel enters the environment, our behavior will take one of three routes: We can ignore it as inconsequential, we can flee if it’s dangerous (or fight if need be), or we can engage it if it seems beneficial (such as a mate or food). So this system involves an inciting incident, rising action, a climax, and a resolution as our body chemistry returns to a baseline level once more.
Thus we are continuously on a roller coaster of rising and falling emotional states aimed at discovering what has changed in our environment, and then taking advantage of the good and avoiding the bad. These emotions are mediated by neurotransmitters (such as dopamine for motivation) and hormones (such as endorphins for reward). The ventral striatum is rich with dopamine receptors. But saying that it’s the adventure center obscures a complex and beautiful process that underlies almost everything we do in this world.
We crave comfort and security. We crave novelty and exploration too. We crave calm and excitement, and we even crave fear. Can we reconcile these seeming contradictions? They are not contradictory. They are intricate, interdependent forces, working together to make what we call life.