Biological groups rely on collective intelligence to solve challenges, but poor coordination can reduce effectiveness. Comparing group and individual cognition is difficult, as they usually address different problems.
However, ants and humans excel at navigating large loads through complex environments as individuals and groups. This task offers a unique chance to compare problem-solving and cognitive abilities across species and group sizes.
In a new study by the Weizmann Institute of Science, scientists compared how individuals and groups of ants or people tackle an identical geometrical puzzle. The team aims to determine who is better at maneuvering a large load through a maze.
The findings offer fresh insights into group decision-making, highlighting the advantages and drawbacks of cooperation compared to individual effort.
The researchers designed a real-world version of the “piano movers puzzle,” a classic problem in motion planning and robotics. This challenge involves figuring out how to move an irregularly shaped object, like a piano, from one point to another through a complex environment. Instead of a piano, participants had to navigate a large T-shaped object across a rectangular area divided into three chambers connected by two narrow slits.
Two different sets of mazes with different sizes were created to match the dimensions of ants, humans, and groups of different sizes. Recruiting human participants was easier: They were asked to participate, probably because they liked the idea of a competition. In the case of ants, they are far from competitive. They were enticed into participating by being tricked into believing the heavy load was a tasty morsel to transport back to their nest.
The ants competing against humans were ‘Paratrechina longicornis,’ known for their long antennae and erratic movement, earning them the nickname “crazy ants.” These small black ants, about 3 mm long, are common worldwide and particularly abundant along Israel’s coast and southern regions.
The maze challenge involved ants in three setups: a single ant, a group of ~7 ants, and a group of ~80 ants. Humans tackled the task in parallel setups: one person, a small group of 6–9, and a large group of 26. To ensure fair comparisons, some human groups were restricted from communicating verbally or through gestures, wearing masks and sunglasses to obscure facial expressions.
Participants could only use handles mimicking how ants carry loads, equipped with meters to measure pulling forces. Each combination was tested multiple times, with researchers analyzing videos, tracking data, computer simulations, and physics models to draw insights.
Humans excelled in the individual challenge, leveraging their cognitive abilities and strategic planning to outperform ants. However, larger groups of ants often outperformed humans in the group challenge. Ant groups demonstrated coordinated, strategic behavior, showing collective memory that helped them persist in inadequate directions and avoid repeated errors.
Humans, on the other hand, saw little improvement in group performance. When communication was restricted to mimic ant-like conditions, their performance declined compared to individuals. Humans often pursued short-term “greedy” solutions, settling for the lowest common denominator, which hindered long-term success.
Feinerman said, “An ant colony is a family. All the ants in the nest are sisters and have common interests. It’s a tightly knit society in which cooperation greatly outweighs competition. That’s why an ant colony is sometimes called a super-organism, a living body composed of multiple ‘cells’ that cooperate with one another.”
“Our findings validate this vision. We’ve shown that ants acting as a group are smarter and that the whole is greater than the sum of its parts for them. In contrast, forming groups did not expand the cognitive abilities of humans. The famous’ wisdom of the crowd’ that’s become so popular in the age of social networks didn’t come to the fore in our experiments.”
Journal Reference:
- Tabea Dreyer, Amir Haluts et al. Comparing cooperative geometric puzzle solving in ants versus humans. PNAS. DOI: 10.1073/pnas.2414274121
