A team of Harvard psychologists has proved that monkeys can tell the difference between a banana and a nabama.

Well, maybe not exactly banana and nabama. After all, monkeys can’t talk. Even though a few chimps learned to sign, they’re hopeless at grammar and possess nothing even remotely resembling human language. Plus, three-syllable banana is a pretty long word for any primate. But a group of tamarins did notice when researchers switched the order of the sounds in a series of two-syllable nonsense words.

This tamarin’s favorite song is “You say banana, and I say nabama . . .”

Technically, what the psych team at Harvard’s Primate Cognitive Neuroscience Laboratory did was familiarize fourteen tamarins with “bisyllabic items conforming to either a prefixation or suffixation pattern” (“Evidence of an evolutionary precursor to human language affixation in a non-human primate” Ansgar D. Endress, Donal Cahill, Stefanie Block, Jeffrey Watumull and Marc D. Hauser, Biology Letters, July 8, 2009 [rsbl.royalsocietypublishing.org]).

They picked prefixes and suffixes because according to the researchers, these forms are often used to produce such important linguistic distinctions as verb tense: “the English past participle is formed by adding the ‘ed’ suffix to the end of a stem (as in talk-ed) . . . . Word-edges appear well suited for some linguistic transformations.” Of course, most forms of the English past participle originally involved, not ‘ed’ suffixes, but the kind of internal sound change that produces such forms as begun, got, sung, flown, come, and been, so we have no idea whether monkeys can distinguish the past participles of the oldest English verbs.

In any case, what the Harvard researchers did, in plainspeak, was to read two-syllable nonsense words consisting of a prefix and a stem, or a suffix and a stem, to a dozen monkeys (two of the tamarins dropped out of the experiment for personal reasons), then read the words again with some prefixes switched to suffixes, and vice versa.

Nine monkeys detected the syllable-switch – a tamarin was judged to have reacted to the change, not by filling in circles on an answer sheet with a No. 2 pencil, but by doing a kind of simian double take, “a head rotation of at least 60 degrees in the horizontal plane . . . if the . . .looking direction was not below that plane at the end of the rotation.” Two tamarins ignored the changed forms. And one reacted ambiguously (it may have gone to sleep).

The researchers concluded that three out of four monkeys have the ability to recognize when a prefix or a suffix changed, and that this suggests that nonhuman primates can make distinctions – in nonlinguistic situations – that become extremely significant in linguistic ones. Tamarins, who have no language, exhibit an awareness that sounds occur in a particular order, a cognitive ability that is necessary, though perhaps not sufficient, for the development of language. Unfortunately, after being liberated from their cages by PETA truth squads, the tamarins ignored all of the sounds that the researchers made trying to get them back.

But since human language depends in part on our ability to know that the order of sounds is significant, the fact that this ability also exists in animals even when they don’t use it as part of their own communication system means that a lot of the cognitive preconditions for language existed long before people became people. But that doesn't mean that monkeys might be able to talk. As the researchers put it, “Unlike other primates . . . infants can use such evolutionarily ancient abilities for purposes that are specifically linguistic and (presumably) unique to humans.”

For example, babies are a lot smarter than tamarins, readily learning that went is the past of go (infants don’t really expect language, or adults, to make much sense). When they later learn that -ed is the general past tense suffix for modern English, they may “correct” their customary went to wented, or even goed. Eventually, without any prompting from laboratory post docs, these same children learn that some “strong” verbs have unsuffixed past tense and past participial forms, while the majority of verbs now use an -ed suffix. They also learn that sometimes that verbal suffix is pronounced “d” (strayed), sometimes “ed” (braided), and sometimes even “t” (walked).

And more amazing still, while both monkeys and babies may be able to tell that banana and nabama are two different strings of similar sounds, babies are able to figure out that both forms can refer to the exact same piece of fruit, and as they grow up and become psychologists, they discover that bananas can have other meanings as well.

To a human baby, it’s a banana and a nabama,

but to a psychologist, sometimes a cigar is just a cigar, and sometimes  bananas means something else entirely.