An aptitude that helps humans string together related items, typically known as a hallmark of human language, is present in primate subjects.
Lab experiments showed that monkeys have an ability that helps them embed phrases with other phrases, according to a publication in Science Advances from June 26.
Linguists say that the skill, referred to as recursion, is fundamental to grammar, and logically specific to humans.
However, the study “shows that the capacity to represent recursive sequences is present in an animal that will never learn a language,” as Stephen Ferrigno, a Harvard University psychologist, said.
Recursion allows us to expand sentences like “The pandemic is terrible” into “The pandemic, which has claimed so many lives, is awful.”
The experiment analyzed recursion in humans and monkeys, too.
Ten adults from the United States recognized recursive symbol chains during a designated nonverbal task. They quickly applied the knowledge they gathered from past phases of the experiment to new strings of items.
The experiment also analyzed 50 U.S. preschoolers and 36 adult Tsimane’ villagers from Bolivia, who have no math or reading knowledge.
The study revealed that the ability to manifest recursion must manifest in an early stage of a subject’s life, as it does not require schooling.
The experiment went on by analyzing three rhesus monkeys, which had a hard time providing similar results to humans. However, after some training, two of them manifested recursive learning, the study says.
One of the monkeys ended up more capable of performing the task than about three-quarters of the preschoolers and approximately half of the villagers.
Ferringo believes that the monkeys’ additional difficulty in learning recursive sequences than people fits the hypothesis that the ability “is evolutionarily ancient and could have been a precursor to the development of human grammar.”