Not only mathematics, monkeys have a memory for grammar too, say researchers. A new study by Harvard University has revealed that primates could intuitively recognise some rules of grammar --in fact, they possess skills needed to use language, which are linked to basic memory functions.
One grammatical structure that is found across many languages is affixation -- the addition of syllables, either at the beginning or end of a word to modify its meaning. For instance, in English, the suffix "ed" is added to verbs to make the past tense.
And, as this structure is found in so many languages, the researchers thought it may well be linked to basic memory functions that are independent of language.
To test this, they studied 14 cotton-top tamarins, which, like all other non-human primates, do not use language to communicate -- they first played a sequence of nonsensical "words" to the monkeys that all had the same prefix.
The following morning, the animals were played a different set of entirely new words. This second set had completely different stems -- brain, breast, and wasp instead of bi, ka, and na -- but were preceded by the same prefix. Mixed in to the new batch of words were a few that violated the familiar prefix pattern by having a suffix instead of a prefix ("brainshoy" instead of "shoybrain").
The researchers hypothesised that, if the monkeys were able to recognise the prefix pattern they had heard the day before, they would be more likely to look at the loudspeakers when they heard a word that violated the grammatical pattern. "This is exactly what they did," the New Scientist quoted lead researcher Ansgar Endress as saying.
The team found the same result if they familiarised the monkeys with words that had suffixes, then mixed in a few prefixes.
"The fact that the tamarins appeared to understand the prefix and suffix patterns without being trained with food rewards, does not prove that they have language and grammar. But it does suggest that their memory is able to recognise certain linguistic patterns," Endress said.
The findings are published in the Biology Letters journal.
