Uniquely Human: The Evolution of Speech, Thought, and Selfless Behavior
by Philip Lieberman

This book describes the scientific experiments that support the conclusion that only humans can speak real languages.
"Human language is creative ... new sentences that describe novel situations or convey novel thoughts." (4)

"rapid vocal communication ... is the key to human progress" (9)

He asserts, but fails to prove "Moral progress ... follows from our cognitive ability, which, in turn derives from our linguistic ability." (10)

He employs a circuitry theory of human brain functions as opposed to a modular theory in which specific parts of the brain are dedicated to performing specific functions. He assumes that species evolved from other species. One of his most significant points is:
"Speech allows us to transmit phonetic segments (approximated by letters of the alphabet) at an extremely rapid rate--from fifteen to twenty-five per second." (37)

Yet "Miller showed that humans cannot identify nonspeech sounds at rates that exceed seven to five items per second." (37-38)

"Transmitted at the nonspeech rate, the sentence would take so long that a listener might well forget the beginning before hearing its end. ... only speech sounds would allow people to understand the meaning of even moderately complex sentences. ... The high transmission rate of speech ... allows complex thoughts to be transmitted within the constraints of short-term memory." (38)

Which convinces me that human language gives us a big advantage in communication, but does not prove that language is necessary to have complex thoughts. In fact I often have an idea that I want to express in writing, but cant's find the right way to say it. I judge my failed attempts to express my own opinions by using my understanding of the English language and comparing what I have written against my unsuccessfully expressed thoughts.
"We appear to have innate knowledge of the filtering characteristics of the human supralaryngeal vocal tract ... that calculates the format frequencies on the basis of an internal representation" (44)

"The speed of human speech derives from our having innate brain mechanisms that are adapted for speech perception. We unconsciously assign patterns of format frequencies and other acoustic cues to discrete phonetic categories. ... The brain mechanisms that do this appear to be matched, that is, tuned to respond to the particular acoustic signals that the human speech-producing anatomy can produce." (45)

"vocal tract normalization is probably innate. ... a three-month-old boy produced frequency-scaled versions of his mother's vowels; his format frequencies were proportional to the ratio between the length of his own supralaryngeal vocal tract and hers." (47)

Nonhuman mammals (and human babies) can simultaneously breathe and drink. "The reduced length of the modern human palate and mandible also crowds our teeth, presenting the possibility of infection from impacted wisdom teeth." (56)

"The only thing that our vocal tract is better for than other animals' is human speech. He goes on to explain the language advantages of our nasal passages, tongues, etc. Neanderthals had nonhuman vocal tracts and so they could not have had languages as efficient as our languages. There is no homo sapien fossil evidence of any intermediate stages between human and nonhuman vocal tracts. (72)

"the format frequency encoding of human speech ... allows us to overcome the temporal resolution of the mammalian auditory system ... encoding syntax ... allows us to overcome memory limitations. ... I propose that rapid, precise vocal communication was the engine that produced the modern human brain." (82)

"Vocal communication's initial contribution to biological fitness probably derives from the fact that it frees the hands." (105)

Human vocalization is controlled by a different area of the brain than monkey vocalizations (which are not under voluntary control). He goes into examples of people (probably only men) who had brain damage to particular areas and how it affected their speech, memory, etc. He seems unaware that women's brains are much less centralized with regard to speech functions than men's brains.

Year Read: 1999


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