Scientists have long been fascinated by collective intelligence, the idea that groups can solve problems better than individuals. Now, an interesting new study reveals some unexpected findings about group problem-solving abilities across species, specifically comparing how ants and humans tackle complex spatial challenges.
Researchers at the Weizmann Institute of Science designed an ingenious experiment pitting groups of longhorn crazy ants against groups of humans in solving the same geometric puzzle at different scales. The puzzle, known as a “piano-movers’ problem,” required moving a T-shaped load through a series of tight spaces and around corners. Imagine trying to maneuver a couch through a narrow doorway, but with more mathematical precision involved.
What makes this study, published in PNAS, particularly fascinating is that both ants and humans are among the few species known to cooperatively transport large objects in nature. In fact, of the approximately 15,000 ant species on Earth, only about 1% engage in cooperative transport of heavy loads, making this shared behavior between humans and ants especially remarkable.
The species chosen for this evolutionary competition was Paratrechina longicornis, commonly known as “crazy ants” due to their erratic movement patterns. These black ants, measuring just 3 millimeters in length, are widespread globally but particularly prevalent along Israel’s coast and southern regions. Their name derives from their distinctive long antennae, though their frenetic behavior earned them their more colorful nickname.
Recruiting participants for the study presented different challenges across species. While human volunteers readily joined when asked, likely motivated by the competitive aspect, the ants required a bit of deception. Researchers had to trick them into thinking the T-shaped load was food that needed to be transported to their nest.
In experiments spanning three years and involving over 1,250 human participants and multiple ant colonies, researchers tested different group sizes tackling scaled versions of the same puzzle. For the ants, they used both individual ants and small groups of about 7 ants, as well as larger groups averaging 80 ants. Human participants were divided into single solvers and groups of 6-9 or 16-26 people.
Perhaps most intriguingly, the researchers found that while larger groups of ants performed significantly better than smaller groups or individuals, the opposite was true for humans when their communication was restricted. When human groups were not allowed to speak or use gestures and had to wear masks and sunglasses, their performance actually deteriorated compared to individuals working alone.
This counterintuitive finding speaks to fundamental differences in how ants and humans approach collective problem-solving. Individual ants cannot grasp the global nature of the puzzle, but their collective motion translates into emergent cognitive abilities; in other words, they develop new problem-solving skills simply by working together. The large ant groups showed impressive persistence and coordination, maintaining their direction even after colliding with walls and efficiently scanning their environment until finding openings.
The study highlights a crucial distinction between ant and human societies. “An ant colony is actually a family. All the ants in the nest are sisters, and they have common interests. It’s a tightly knit society in which cooperation greatly outweighs competition,” explains study co-author Prof. Ofer Feinerman in a statement. “That’s why an ant colony is sometimes referred to as a super-organism, sort of a living body composed of multiple ‘cells’ that cooperate with one another.”
This familial structure appears to enhance the ants’ collective problem-solving abilities. Their findings validated this “super-organism” vision, demonstrating that ants acting as a group are indeed smarter, with the whole being greater than the sum of its parts. In contrast, human groups showed no such enhancement of cognitive abilities, challenging popular notions about the “wisdom of crowds” in the social media age.
