Babel's Dawn

Ape Cries Are Complex

An orangutan gives the thumbs up sign. (Story here.)

In his book Origins of Human Communication Michael Tomasello argues that language began as gesture alone and at some point vocalization joined in and eventually took over as the main linguistic “modality” although gesture has remained and important. (This blog has made four posts about Tomasello’s book [#1, #2, #3, #4]). The evidence offered for this scenario is threefold:

First, many ape gestures are individually learned and flexibly used, including in combination, whereas this is not true of ape vocalizations.

Second, many ape gestures are used with attention to the attentional state of the recipient, which is mostly not even relevant in ape vocal communication. …

It is also important evolutionarily that gestural communication is more sophisticated in apes (humans’ closest relatives) than in monkeys and other mammals, whereas something close to the opposite is true of vocal communication. [p. 35]

A paper in the September 11 issue of Cerebral Cortex, however, suggests that Tomasello may have been underestimating the nature of ape vocalizations.

Speech Includes Gesture

Some gestures stay in the mind as sharply as the most memorable phrase.

Simone Pika has published a useful review of ape gestures in the First Language journal, “Gestures of apes and pre-linguistic human children: Similar or different?” (abstract here). I don’t suppose it will bowl anyone over with its finding that while both apes and children can make imperative gestures (e.g., give me food) human children, but not apes, also make “gestures for declarative purposes to direct the attention of others to some third entity, simply for the sake of sharing interest in it or commenting on it” [p. 131]. But when all the different sorts of ape gestures are drawn together it is quite evident that the really peculiar aspect of speech is the presence of what this blog calls the speech triangle, and what Pika calls triadic form. That is, humans are peculiar in having a speaker, a listener, and an outside topic.

Dyadic gestures—actions used to attract attention to the actor—are common enough among apes, but informative triads among apes in the wild are almost unknown. (The one exception: a free bonobo once was observed probably pointing out human observers hiding in the bushes.) Pika says a little ambiguously, “It is therefore quite puzzling why only human beings comment on outside entities simply to share experiences.” I would put it a little differently. It’s quite puzzling how we came to comment on outside entities when no other animal seems to share the need. Once we can give a solid explanation for that puzzle, we will have come a long way in understanding why humans are different.

The Latest on the FoxP2 Gene

Echolocating bats fly in the crowded darkness and find food.

Surprising news from China finds extensive indications of evolution in the so-called language gene, FOXP2, among bats that use echolocation to find prey on the wing. The FOXP2 gene was first identified as an object of special interest when it was found that a family with a hereditary speech disorder had a mutated FOXP2 gene. Further examination of this gene found that it was unusually stable. Mice, gorillas, and chimpanzees have almost identical FOXP2 genes, while the human FOXP2 gene differs from the chimpanzee’s by two adaptive amino acids. A further exploration found that rabbit, marmoset, armadillo, baboon, and orang utan FOXP2 genes are very stable. This kind of stability argues that the gene is already optimal and allows for very little drift. A team led by Gang Li of the East China Normal University in Shanghai has a new paper available online from PloS One (here) that reports their discovery about bat FOXP2 structure in considerable detail. Bats may seem an unlikely source for any insight into speech, but the paper makes a strong argument against that prejudice. Bats are great vocalizers and, like humans, must attend to very brief differences in sounds if they are to understand the meaning of what they hear.

Songs and Language

Gibbons "sing" in the trees. You can see and hear them on YouTube.

IThe most traditional approach to language evolution begins by looking at animal vocalizations and imagining some kind of extension of them led to speech. The trouble with the from arf-arf to howdy-miss hypothesis is that it leaves out the insertion of meaning, syntax, joint attention, and voluntary motor control. Yet vocalization is so common in the animal world, and can be so very elaborate among primates, that vocalization is difficult to dismiss entirely as a pathway to speech. Perhaps part of the appeal of the idea that speech began as gesture lies in the way the approach throws all previous animal vocalizations and aside and gives evolution a blank slate to work with. The January issue of Developmental Science proposed a more promising avenue around the impasse. A Japanese primatologist, Nobuo Masataka, proposes in an article titled, “Music, evolution, and language” (here) that animal vocalizations led not to speech but to song.

Scylla and Charybdis

Here’s a great title, “Why don’t chimps talk and humans sing like canaries?”

It was used by three Swedish scholars, Sverker Johansson, Jordan Zlatev, and Peter Gärdenfors in a note offered last summer (abstract here) in Behavioral and Brain Sciences. They argue that the two critical questions which must be answered in any account of speech origins are:

• Why don’t we just make meaningless sounds the way birds (and many other species) do? What was so special that our speech requires meaningful content?
• Why don’t chimpanzees make meaningful sounds the way we do? What was so special about human origins that our ancestors were selected for speech while the chimpanzee line felt no such selective pressure?

These two questions serve as the Scylla and Charybdis of the speech-origins search. If one doesn’t sink you, the other one probably will.

The Persistent Burden

This blog has been looking at a long article by John L. Locke and Barry Bogin, accompanied by open peer commentary, that appeared last summer in Behavioral and Brain Sciences. Yesterday’s post (here) reported a theory that because of their immaturity and dependence on being carried, the infants of bipeds became a unique form of persistent burden to their parents.It is this persistent-burden factor that Locke/Bogin and their peer commentators Oller-and-Griebel see as something new in primate history, demanding a new answer. Young birds are a burden to their parents as well, but not a burden that goes on for years. Elephants have as long a youth as humans, but elephant infants are on their feet and walking with the herd from the day they are born.

Infant Babbling

In a post last week (here) I noted an article that appeared this summer in Behavioral and Brain Sciences, “Language and Life History,” by John L. Locke and Barry Bogin. The article was followed by extensive “open peer commentary.” (Links to abstracts and open peer commentary here.)  Altogether the journal provides 65 pages of extensive coverage of speech, its evolution and development in individual speakers. From time to time this blog will explore one of the discussion’s themes. Last week we noted that there appear to be two distinct, equally unique threads of vocal communication, emotional and meaningful. Today I want to look at Locke and Bogin's treatment of infant babbling and the rise of the emotional thread.

The Long Parenthood

Over the holiday break I noticed an ad that had appeared on New York's subways, saying in very large letters, "Never shake your baby." The need for such warnings is a reminder of how maddening the unrelenting demands of a baby can be. Recently several scholars have brought that issue to a consideration of speech origins. Notably, last summer there was an extensive discussion in Behavioral and Brain Sciences about "Language and Life History: A New Perspective on the Development and Evolution of Language" by John L. Locke and Barry Bogin (Links to abstracts and open peer commentary here.) After reading it I feel I have a better sense of why most parents don't slip up and shake their babies to death.

Hey Daddy-O

Mama and papa are “the best phonetic candidates” for words still in use today that were known long before Homo sapiens, according to two papers presented at the Stellenbosch conference on “Language in the Cradle” by Alain Matthey de l’Etang, Pierre J. Bancel, John D. Bengtson, and Merritt Ruhlen, hereafter referred to as the Stellenbosch Team. (Abstracts here: 1 2)

Cheep! Cheep!

Our regular post returns Monday, in the meanwhile you can check out news that songbirds alter their songs to meet the needs of urban environments. With so much noise pollution birds have a hard time being heard, so they have adapted their songs to carry above the city's racket. This blog's position that speech is used for joint attention means that songbird communications are not a form of language, but their flexibility still makes for a good story. (Press release here.)