Eve Spoke
Philip Lieberman, 1998

Chapter 1. The Mice Talked at Night
Lieberman begins by describing an experiment in which he tested speakers for articulation precision and cognitive abilities high upon a Himalayan peak. He then reviews the evidence suggesting that modern humans evolved from a single African stock, which then migrated around the world, and considers the
linguistic theories of Noam Chomsky . We are then treated to a quick tour of acoustic phonetics and a description of the overlapping nature of phonemic signals in an acoustic speech signal, this followed by a glance at some of the mechanics of Darwinian evolution and some of the problems faced and solved during the developent of human speech.

Chapter 2. Chimpanzees and Time Machines
Chimpanzees use natural materials as tools and even modify them slightly for specific applications, such as opening beehives, cracking nuts and fishing ants or termites from their colonys. Lieberman argues that the complexity of the tools used by a particular culture, chimpanzee or early man, is a factor of the accumulated cultural tradition of the time and does not directly indicate the level of brain development. Having just said that, he then draws a tentative conclusion about the brain capacity from the maximum level of tool development across various geographically isolated societies. He raises the puzzling issue of why Homo erectus did not advance much in the complexity of their stone tools across a million-year period of increasing brain size.

Two facts emerge about the limits of chimpanzee vocalization. The story of Figan (p 32) shows that he found it extremely difficult to suppress the urge to call out his good fortune after having been given a personal supply of bananas. Another side of the coin is shown by the lack of speech development in a number of chimps raised in human cultures. The much-debated question of sign language seems to show a similar lack of linguistic skills. The chimps never go beyond a vocabulary of about a hundred items and never show evidence of complex syntactic ability, either in the use of hand signs or with symbolic keyboards.

The chapter ends with a slightly more detailed description of the comparative anatomy of the vocal tract between chimps and humans.

Chapter 3. He's a Big Baby
After recapping the establishment of Haskins Laboratories in their first location in New York City, Lieberman describes his search for information on neonatal anatomy, which led to a meeting with Ed Crelin of the Yale University School of Medicine. Crelin had just written the first study of the anatomy of newborn infants. Upon seeing Lieberman plaster cast of a Neanderthal skull, Crelin remarked, "He's a big baby".

Liebermen compares various measurements of that skull with those of a newborn and an adult modern human. He is particularly interested in the palatal area and the spacing between there and the spinal cord, in which the larynx must fit. Based on his knowledge of infant bone and soft tissue configurations and using the Neanderthal skull casting, Crelin attempted to reconstruct what might have been the Neanderthal's vocal tract tissue shapes. The result was a plaster cast perhaps similar to the shape of the vocal tract cavity of the early hominid.

In both the newborn and, apparently, the Neanderthal, the larynx is positioned high enough that it can be brought into contact with the nasal opening, sealing off the breathing pathway from the food pathway. In an adult, the larynx descends, by selective bone growth of the neck, placing it well below the nasal opening. Related changes in the soft palate arrangement allow the adult to open and close the nasal opening during speech, which the Neanderthal apparently could not.

The major effect of this rearrangement of the larynx is an increase in the range of vowel sounds which can be articulated, due to the increased length of the lower vocal tract from the larynx to the tongue body. This is because the formant frequency ranges of the vowels are determined by the ratios of the lengths of the portions of the tract in front of and behind the narrowest point, usually where the tongue body is brought upward toward the palate.

Lieberman reviews work by Peterson and Barney on the formant frequency structure of vowel spaces and by Ladefoged and Broadbent on the perception of vowels under different circumstances. Studies by Nearey and Lindblom showed that hearers normalize the acoustical characteristics before classifying the vowel (Lieberman does not give references for this work). See Opinion .

Confirming the other major point of this chapter, Lieberman cites Zinni Bond's work (and others) showing that nasalized speech is less intelligible than non-nasalized speech. He closes the chapter stating that Neanderthal would certainly have been able to speak, but would not have had the full range of phonetic distinctions equal to the later Homo sapiens. This is a good point to note that Lieberman gives the impression, without definitely saying so, that the species of the Neanderthal man was Homo Erectus. The web site of the Museum of Anthropology in Philadelphia states that Neanderthal was classified as Homo sapiens.

Chapter 4. Dead Men and Women Talk Again
Lieberman is quite sure that Neanderthal had some sort of language although he is not so sure how well developed the language faculty might have been. They had brains on the order of 1200 to 1700 cc, comparable to modern Homo sapiens. Even allowing for the difference in body mass, this is large, 4 times the size of the brain of a 100 Kg gorilla. What could that brain do? Falk and others have argued that the parietal- temporal (Broca's) area was well developed, based on the analysis of casts of the inside of the skull. Lieberman acknowledges severe difficulties in drawing conclusions about brain capabilities from vague hints of brain shape related to the interior skull shape.

So where are we? Brain size is measurable. The Australopithecines, 4 to 5 million years ago, had brains around 400 to 500 cc, not much different than today's chimpanzee. By 2 to 3 million years ago, Homo habilis' brain had grown to 500 to 800 cc. Homo erectus, 1.9 million years ago, had 700 to 1200 cc of wet goop in his head. What did they do with it? One place to look is tool development.

Chipped stone cutting tools have been found at Olduvai and many other comparable sites with dates ranging from 1.5 to 2.5 million years. Following Toth and Schick , Lieberman argues that the tools show increasing development of the hand and hand movement coordination. Toth taught himself how to make such tools in order to better understand the process. In addition to acquiring the needed skills, he claims to have learned something about handedness. His tools and chips showed his right-handedness.

Although brain lateralization has been associated with language, it is in fact a very old characteristic. Birds, frogs and several other very old species show various lateralization effects. Denenberg has shown that individual mice tend to use a particular front paw for reaching, although the species as a whole is evenly divided between left and right. Lieberman speculates that the same was true for Autralopithecone man, and that we happen to be descendents of a right-handed tribe.

Switching back to tools, Lieberman notes the rather curious rate of development of tool sophistication. The Olduvan-style cutting tools were in use with little change for millions of years. About 1.5 million years ago, the cutting edge became somewhat smoother. Some accounts hold that such tools continued in use until as late as about 35,000 years ago and that, suddenly, they were supplanted by bone needles, polished stone, ornaments, sculpture and paintings. Lieberman believes these accounts are too strong. He notes that Homo erectus used fire, possibly for driving hunted animals as well as for cooking.

Chapter 5. Talking and Thinking Brains

Chapter 6. What, When and Where Did Eve Speak to Adam, and He to Her?

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