DISCUSSION

Jan Wind, Moderator Anthropological Institute

Vrije University Amsterdam-101 I , The Netherlands

DEAN FALK (University ofMichigan. Ann Arbor, Mich.): I'd like to address this to Professor Lieberman. This is about the placement of the hyoid bone in the Lachapelle. Professor DuBrul earlier pointed out that the hyoid bone has been placed above the inferior edge of the mandible, and according to Professor DuBrul, this would prohibit opening of the mouth.

In July 1 published an article in the American Journal of Physical Anthropology, where 1 said that this would prohibit swallowing. You did respond earlier a little bit, and now I agree with DuBrul that, yes, if I'd step on its head it would swallow or open its mouth. I would like to hear your response to our criticisms of this placement of the hyoid bone, but first of all I would like to say that in my article 1 did demonstrate that in fetal chimpanzees, adult chimpanzees, infant humans, and adult humans, placement of the hyoid bone is below the inferior edge of the mandible, not above it. So I think the evidence would support a n inferior placement of the hyoid bone. And you have to look at the function of the hyoid bone for whatever it is, opening of the mouth or swallowing.

DR. LIEBERMAN: First of all, the Neanderthal mandible, as it develops, tends to get very much more massive. If you look at the infant Neanderthals, the adolescent and Neanderthals in Vleck's work, you see a much more gracile form of mandible in which the hyoid placement would essentially be that of a n infant. As the mandible gets more massive to support this very elaborate array of teeth, you just get more elaboration at the back.

Now, so far as the study about the function of the hyoid, your point in your paper was that the hyoid placement would prevent motion of the hyoid in the vertical plane in Neanderthal. In human swallowing, the hyoid goes up and down quite a bit: that's necessary for swallowing. However, this is not the motion of swallowing in an animal like the newborn. In the Trube and Bosma data on swallowing, the hyoid moves in the anterior posterior dimension. Of course Negus noticed this. This is also the case with chimpanzee. The low placement of the hyoid could no more have interfered with swallowing in Lachapelle than it does in swallowing in chimpanzee, gorilla, dog, and so on. In other words, they don't swallow the same way, they don't have to swallow the same way. It's sufficient for the hyoid to move in the anterior posterior dimension.

DR. FALK: Could I just make a brief response to that? I . The hyoid bone of newborn humans has been located below the inferior edges of the mandible. 2. In Lachapelle as you have reconstructed it, the hyoid bone has been placed a full half- length of the mandible forward. I maintain that this would mess up swallowing in chimpanzee-like organisms but that's relative to my own interpretation of how chimps swallow.

3. Maybe if you just lower it a little bit it wouldn't make too much difference. But I would hope that maybe you'd d o that, go ahead and reconsttuct and reinterpret. That's what I would like to see done.

DR. LE MAY: I wanted to speak about Dr. Lieberman's work. 1 think the search for the beginning of vocalization is very interesting, but 1 feel strongly that one should use all possible pertinent data from modern man when speculating about the

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functional abilities of fossil man. As a radiologist 1 frequently see x rays of skulls of persons who have led successful, vocal lives but come in for films of the head because of injuries or recent onset of neurological symptoms. It is not rare to see in x rays of such individuals that the length of the hard palate is shorter than the distance between the palate and the basion; i.e., the anterior margin of the superior end of the spinal canal-a finding Professors Lieberman and Crelin described as occurring mainly in newborns and Neanderthal man (rarely in modern man), and which they used in designing the vocal tract of Neanderthal man. Modern, normally intelligent and successful adult persons do not rarely have a hard palate longer than the distance from the palate to the basion.

In addition, we know that the face continues to develop after the endocranial portion of the vault no longer enlarges. I measured the length of the palate and the palatal-basion distance on skull films of 64 children between the ages of 5 and 15 years studied a t Boston’s Children’s Hospital. Of this group, 51 of the 64 had hard palates which were shorter than the P-B distances. So we see that not just Neander- thal and newborn individuals but some normal adults and most children have a throat of this configuration.

Another factor used by Lieberman and Crelin in their design of the vocal tract of Neanderthal man was the location of the larynx as determined by the direction of the styloid process from the skull. The main skull they used for their model of the level of the larynx was that of La Chapelle-aux-Saints. The base of this skull, 1 have been told, was broken and has been rebuilt; and the styloid processes project less than 1 cm from the vault. By studying x-ray films of the pharynx of modem man, we must conclude that we could not with certainty determine the exact level of the hyoid bone and larynx by using the angle of the styloid process, because the base of the styloid often extends fairly horizontally from the skull and then the styloid turns downward. At other times, on films of the pharynx of modern man we see the styloid extending sharply downward from the skull and then turning forward; so I d o not believe it is possible to locate the larynx by a short styloid process, such as that portion remaining on the La Chapelle-aux-Saints skull, and 1 feel that Professors Lieberman and Crelin need more hard evidence than they have presented to date to provide a convincing basis for their hypothesis.

DR. LIEBERMAN: Dr. Le May has, unfortunately, not followed the continuing discussion of the reconstruction of the supralaryngeal vocal tract that was reported in Lieberman and Crelin in 1971; cited in this volume. The points that she raises have been answered before, and the basis for the reconstruction is reviewed in the paper that I presented at this meeting. I’ll attempt, however, to summarize the discussion.

1. The reconstruction is not based on comparing a few isolated features in newborns and classic Neanderthal. The particular skeletal features that were noted were cited as examples of the total skeletal complex that is similar in newborn humans and classic Neanderthal skulls. We noted in 1971 that some of the skeletal features that always occur in newborn humans and classic Neanderthal sometimes occur in adult humans. We specifically noted that some adult humans also have a long palate-to-basion distance. This simply reflects the fact that the course of human development is not uniform and that in the process of maturation some individuals retain some of the skeletal features that are typical of newborns. Normal adults, however, d o not retain the total skeletal complex that correlates with the soft tissue of the newborn supralaryngeal vocal tract. If Le May wants to replicate our reconstruction the appropriate animal is the human newborn, where the total complex is preserved. The palate-to-basion distance never was offered as a “crucial” factor that in itself would suffice to reconstruct a vocal tract.

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2. Dr. Le May’s comments on the small fragments of the styloid process on the La Chapelle skull and the changes in angulation of the styloid, etc., reveal that she has also missed the fact that Crelin determined the angulation of the styloid from the base of the styloid. The base is present in the fossil remains of La Chapelle-aux- Saints and other classic Neanderthal fossils. There is plenty of other fossil evidence available as well as statistical studies like those of Howells and Berglund that demonstrate that normal adult humans and classic Neanderthal fossil skulls fall into two metrically different populations.