Wasps have passed this logic test, can you?

Let's see, a surprise test: Juan is bigger than Pedro. Pedro is taller than Miguel. Who is the greatest, Miguel or Juan?

If you said Juan, congratulations! You have just demonstrated what is called "transitive inference", that is, the ability to compare things indirectly on the basis of earlier juxtapositions. But before you consider yourself gifted, know that it has recently been shown that this ability is also possessed by another creature: the humble wasp-paper that could now live in your garden.

In the summer of 2017, researchers from the University of Michigan tested transitive inference on two species of wasps on paper. A statistically significant number of times, the wasps were able to solve the tests. Other animals, such as rats, geese and cichlids have also demonstrated this ability. But this study, published May 7 in Biology Letters, is the first to successfully show that invertebrates have it too (in 2004, honey bees failed a similar exercise).

Paper wasps inhabit every continent except Antarctica. Maybe now you are close to some. "They usually nest in the eaves of houses or inside barbecues," said Elizabeth Tibbetts, the study's principal author.

In a previous survey, Tibbetts had shown that female wasp specimens could identify each other by means of their distinctive facial patterns, which resembled Rorschach's test stains. "When we see two wasps for the first time, they learn:" Oh, that's what Susanita looks like. "And when they meet, they remember who Susanita is," she said.

In the spring, females spend a lot of time fighting, hugging and caressing each other. These attacks are like college quarrels. "Some wasps are fighting, others are just watching the fights," Tibbetts said. "These are very exciting moments." Wasps remind those who lose and win, and use this context to establish a social hierarchy: the strongest breed while the weakest do all the work.

Tibbetts and his colleagues wanted to see if the wasps could go a step further. Suppose a paper wasp defeated Susanita, then I saw Susanita knock out Juanita a few days later. Could this wasp realize that she would probably also win Juanita?

This reasoning requires a transitive inference. The team is therefore focused on what is called the "five-element training procedure", which is now a standard way to test this ability in animals. The wasps were placed in different two-color cameras. If they moved in the wrong color, they felt a slight electric shock. In this way, "you train them to know that blue is better than green, and once they learn it, you teach them that green is better than purple," said Tibbetts. They did it with four pairs of five colors.

After forming the wasps, they put them in a new camera in the colors they already knew for training, but they had not badembled. About 67% of the time, wasps were able to choose the "best" color, that is, the one that was least likely to shock them.

"They organize all these couples in a linear hierarchical head," said Tibbetts. Now think about how wasps use this skill in real social interactions.

Colin Allen, a cognitive philosopher at the University of Pittsburgh, warned that one should not overinterpret the results of the study, claiming that the simplicity of the test makes it "difficult to judge the processes that work in these wasps ". However, he states that "it's an important reminder", it's not because bees can not do something that other insects can not.

This is consistent with another lesson of the study: that humans can do something, does not necessarily mean that no insect can do it.

* Copyright: 2019 The New York Times Press Office