When the fish stop biting, ice fishermen follow the crowd

Winters are long and freezing in North Karelia, a Finnish state on the Russian border. Many locals spend their time sitting on a frozen lake, fishing rod in hand. Once settled in a comfortable location, anglers must decide how long they will stay there before braving high winds and knee-deep snow to travel to a new location or even a nearby lake.

The decision-making process of ice fishermen loosely mirrors that of subsistence strategies in the wild. Over time, people had to mentally calculate how long it took to gather resources in a given area, whether harvesting berries, foraging for tubers, or luring fish under a thick layer of ice, before expending the energy and time to head elsewhere.

Existing research on human diet assumes that ice fishermen rely primarily on personal knowledge when choosing or leaving a location. But this research is largely based on solitary foragers. And often, these “foragers” are online video game players, trying to obtain as many resources as possible in the air-conditioned comfort of a laboratory.

In real life, gatherers – or fishermen, in this case – typically search for resources alongside others. And rather than charting their own path, which is a risky move in a hostile environment, they can instead choose to follow the crowdthe researchers report on January 29 in Science.

Going it alone and the wisdom of the group are “almost equally important,” says Alexander Schakowski, a psychologist at the Max Planck Institute for Human Development in Berlin. In fact, unlucky anglers are more likely to stick with others than to trust their instincts, his team’s new study suggests.

Understanding how humans make foraging decisions in extreme environments – from the tropics to the Arctic – suggests the evolution of complex thinking, researchers say.

“It gives us more information about what drives intelligence,” says Friederike “Freddy” Hillemann, a behavioral ecologist at the University of Durham in England who was not involved in the study.

In the Nordic countries, to find food, it has long been necessary to drill through thick ice to access fish. Subsistence ice fishing may be less common these days, but sport fishing remains extremely popular, with events held in Finland attracting thousands of competitors.

So, as a natural experiment, Schakowski and his colleagues held ice fishing competitions throughout North Karelia. During 10 tournaments in 2022 and 2023, 74 competitors participated, including 31 individuals who took part in all competitions. Aquatic ecologist Raine Kortet of the University of Eastern Finland in Joensuu, who is passionate about ice fishing, recruited the region’s best fishermen. (Schakowski, for his part, admits he’s a fisherman out of water. “I tried it once. I didn’t really succeed. I didn’t really know what to do if I caught a fish,” he says.)

Participants had three hours to catch as many pounds of perch as possible. Top finishers received cash prizes and bragging rights. Competitors wore GPS trackers and head-mounted cameras so researchers could observe how they made decisions on the ice.

Competitors had 15 minutes to find their first place, with most giving up a spot without a bite within minutes. Fairly quickly, individuals began to cluster together to form groups of five to 10 people, Schakowski said. But these groups did not resemble friendly alliances; the competitors spoke little and often sat back to back to hide their catches.

Analysis of the video footage showed that fishermen tended to rely on their personal successes when deciding whether to stay or leave a location. And they were more likely to abandon their solitude and join a crowd when they didn’t have much luck catching fish.

The lake environment itself, such as fishermen prioritizing steep areas of the lake bottom where fish are expected to seek refuge, played less of a role than expected. Environmental cues might play a bigger role in other places where the terrain is more variable, Schakowski says. A single study of a single community cannot capture the myriad cues and practices that humans have adopted in their perpetual search for food.

It’s no surprise that ice fishermen stick together, says anthropologist Michael Gurven of the University of California, Santa Barbara. “We are social creatures, and almost everything we do involves looking over our shoulders and seeing what other people are doing.”

Gurven and Hillemann suggest the team take their work further and survey ice fishermen to see how they describe their decision-making process. This work has a clear advantage over dietary research on other animals, says Hillemann. “We can talk to people.”