They build cities. They farm. They make war. Ants do a lot of things that seem uncannily human — and yet they're profoundly alien, part of a hive mind called a social organism. What does that feel like to each individual ant? Now a new scientific paper suggests that there is always doubt in the hive mind.
Photo by Alex Wild
Over at New Scientist, Karl Gruber describes the work of two scientists who recently published a paper in Proceedings of the Royal Society B about a strange form of ant behaviour. When ants go in search of food, they lay down a "scent trail" behind them that serves as a kind of chemical signpost for other members of their colony. But what happens when ants return to their own scent paths, and discover that the food it points to is gone?
Tomer Czaczkes and Jürgen Heinze from the University of Regensburg in Germany let black garden ants find food on a T-shaped maze, with the food always in one arm. Then they switched the food to the other arm, creating uncertainty for the ants.
Ants that headed in the wrong direction were less likely to leave a trail for the other ants to follow.
"It makes, sense," says Czaczkes. "You don't want to give your sisters wrong information."
He says this might show that ants can question their own knowledge, a basic facet of higher metacognition — awareness of one's own thoughts — although it doesn't prove this.
Basically, the researchers found two clues about ant consciousness. One, as Czaczkes suggests, it appears that ants experience uncertainty. They "question their own knowledge," wondering whether they are on the trail to an actual reward, versus a possible reward. This questioning is at the root of a sophisticated mental modelling technique called metacognition.
This finding also suggests that individual ant agency is a key part of the social organism. These ants are not blindly following in the scent paths of their sisters. They are always revising those paths, and seem open at any time to reconsidering a particular direction. Without individual ants making these choices, the colony would collapse.
Even though ants work collectively, often sacrificing their lives in extraordinarily selfless ways to save the colony, they are also working as individuals. Perhaps being part of a social organism doesn't feel that much different from being part of human civilisation after all.
[read the full scientific paper at Proceedings of the Royal Society B]