Foraging in the Modern World

I live in a town with hundreds of restaurants serving many of the world’s cuisines: Sushi bars, pizza parlors, pho, tapas, KFC, you name it. My family eats out a fair amount, and we know and appreciate all these tastes, so we could conceivably explore a different menu every outing. But we don’t. Some years ago we discovered a neighborhood café that we all really like, and that’s pretty much where we go. It’s our place.

I know that other people are different. We’re basically opting for certainty and predictability, where others prefer exploration and change. But why do people differ on this trait? What motivates some to constantly seek out the next best thing, the greener grass, while others of us are content to stick with what’s known and safe? How do we know there’s not a new and better favorite eatery just around the corner? Are we trading off curiosity and novelty for the luxury of not having to make a decision?

Psychologists are very interested in this question, and some believe it may reflect a fundamental difference in cognitive style, wired into our neurons. Think of it this way: Our ancient ancestors had to forage in the savanna for food and water, but there was no telling where they would find these resources. The environment was patchy, with a watering hole here and an antelope herd there, but no uniformity or predictability. So what was the best search strategy? Once you find a hunting ground with some antelope in it, do you set up camp and make it your own, or go looking for a better hunting ground, then a better one still?

Now fast-forward to modern times. Our challenges are perhaps more intellectual and abstract, but we still have to decide how to deal with an uncertain world. Faced with a problem or decision or choice, do we bear down and exploit one idea for all it’s worth, or move rapidly on from one solution to another to another? Or maybe we do both, depending on the problem, toggling back and forth depending on what works.

Indiana University psychologists Thomas Hills, Peter Todd and Robert Goldstone decided to explore these questions in the laboratory. They wanted to see if people do indeed have a consistent cognitive style for foraging, whether it’s for food or ideas. They also wanted to see if priming those ancient foraging neurons—triggering either exploring or exploitation instincts—influences the way people approach modern problems.

Since they couldn’t actually ask people to forage for food in the wild, they used some modern tools: a computer game and a board game. They had a group of volunteers use icons to “forage” in a computerized world, moving around until they stumbled upon a hidden supply of food or water, then deciding if and when to move on, continue the search, and in which direction, and so forth. The scientists tracked their movements.

But the volunteers explored two very different worlds: Some foraged in a “clumpy” world, which had fewer but richer supplies of nutrients. Others explored a “diffuse” environment, which had many more, but much smaller, supplies. The idea was to “prime” the optimal foraging strategy for each possible world. Those in a diffuse world would in theory do better giving up on any one spot quickly, and moving on rapidly, and navigating to avoid any duplication. Those in a clumpy world would be more likely to stay put, exploiting the rich lodes of nutrients rather than keeping up the search.

That was the first part of the experiment. Afterward, the volunteers participated in a more abstract, intellectual search task: the board game Scrabble. They didn’t actually play Scrabble, but they got letters as if they were going to play, and had to search their memory for as many words as they could make with those letters. As with the board game, they could also choose to trade in their letters for new ones, but in the experiment they could do it whenever they wanted to. The wholesale trading of letters is what the psychologists were actually observing: They want to compare the volunteers’ Scrabble strategies with their foraging strategies, to see if they stuck with the letters they were given—or rapidly abandoned one set of letters for another (more promising) set. In other words, would those who were mentally primed for a clumpy world see their Scrabble letters as rich clumps, worth sticking with, while those primed for a diffuse world quickly abandoned one set of letters for another?

The results were striking. As reported in the August issue of the journal Psychological Science, those whose neurons were primed for exploration in the wild, were also more restless and exploratory in Scrabble, while those primed for exploitation were more focused and persevering when they switched to the abstract mental challenge. Put another way, the human brain appears capable of toggling back and forth between exploration and exploitation, depending on the demands of the task.

But the psychologists also found that individuals were consistent in their cognitive style. That is, the most persevering foragers were also the most persevering Scrabble players, just as gadabouts in the food search tended to be gadabouts in intellectual matters as well. And presumably in life: They would probably be too antsy to settle for a “good enough” neighborhood café.

But dining out is trivial, and these findings have more serious implications related to other recent work on brain chemistry and cognitive disorders. Exploratory and inattentive foraging—actual or abstract—appears linked to decreases in the brain chemical dopamine. Similarly, many problems related to attention—including ADHD, drug addiction, some forms of autism and schizophrenia—have been link to such a dopamine deficit. It’s possible, the psychologists say, that computer foraging might reveal underlying cognitive style—either persistence or the lack of it. It’s even possible that such simulated foraging could have long-term effects on thinking style, and possibly even lead to therapies for such cognitive disorders. That’s something worth exploring.

For more insights into the quirks of human behavior, visit “We’re Only Human . . .” at www.psychologicalscience.org/onlyhuman. Excerpts from the weblog also appear in the magazine Scientific American Mind and at http://www.sciam.com/.