p. 243
“The human cochlea is so sensitive that it can detect vibration as small as the diameter of an atom (0.3 nm ) and it can resolve time intervals down to 10μ s . . .”
Hudspeth, A. J. (1997). How hearing happens.
Neuron
19: 947-950.
p. 244
“. . . some animals employ systems that are exotic compared to ours.”
Hughes, H. C. (1999).
Sensory Exotica: A World Beyond Human Experience.
Cambridge, MA: MIT Press.
“Sharks have an
electrical
sense . . .”
While snorkeling in the Caribbean last spring, I actually heard the electrical discharges of tropical fish for myself, which sounded like a high-pitched, rapid clicking sound. With human ears, I could hear but not localize the source; the sharks’ sense would be distinct from hearing and permit them to locate their prey.
p. 245
“The basic function and structure of genes is also common to all animals . . .”
See: Colamarino, S., and M. Tessier-Lavigne. (1995). The role of the floorplate in axon guidance.
Annual Review of Neuroscience
18: 497-529. Deacon, T. W. (1997). What makes the human brain different?
Annual Review of Anthropology
26: 337-357. Friedman, G., and D. D. O’Leary. (1996). Retroviral misexpression of engrailed genes in the chick optic tectum perturbs the topographic targeting of retinal axons.
Journal of Neuroscience
16(17): 5498-5509. Kennedy, T. E., T. Serafini, J. R. de la Torre, and M. Tessier-Lavigne. (1994). Netrins are diffusible chemotropic factors for commissural axons in the embryonic spinal chord.
Cell
78: 425-435.
“. . . Balaban removed the auditory cortices from Japanese quail embryos and surgically implanted them into the brains of embryonic chickens . . .”
Balaban, E., M. A. Teillet, and N. Le Douarin. (1988). Application of the quail-chick chimera system to the study of brain development and behavior.
Science
241(4871): 1339-1342.
p. 248
“During a typical day, chimpanzees . . . associate in temporary parties that vary in size and membership, much as humans do.”
Ujhelyi, M. (1996). Is there any intermediate stage between animal communication and language?
Journal of Theoretical Biology
180(1): 71-76.
“. . . biologists have found an inverse relationship between brain size and digestive tract size . . .”
Allman, J. M. (1999).
Evolving Brains.
New York: Scientific American Library/W.H. Freeman.
p. 249
“The total amount of energy available to an organism is limited, forcing an evolutionary trade-off between brain size and digestive tract size.”
Aiello, L, and P. Wheeler. (1995). The expensive tissue hypothesis: The brain and the digestive system in human and primate evolution.
Current Anthropology
36: 199-221.
“Geneticists found that humans have lost an ability . . . to create vitamin C internally . . .”
Ha, M.N., F. L. Graham, C. K. D’Souza, W. J. Muller, S. A. Igdoura, and H. E. Schellhorn. (2004). Functional rescue of vitamin C synthesis deficiency in human cells using adenoviral-based expression of murine l-gulono-gamma-lactone oxidase.
Genomics
83(3): 482-492. Stone, I. (1979). Homo sapiens ascorbicus, a biochemically corrected robust human mutant.
Medical Hypotheses
5(6): 711-721.
“. . . big brains carry with them a high biological price tag . . .”
This passage borrows liberally from: Allman, J. M. (1999).
Evolving Brains.
New York: Scientific American Library/W.H. Freeman, p. 160.
p. 250
“Well-connected female baboons have more babies who receive better care . . .”
Zimmer, C. (March 4, 2008). Sociable, and smart.
The New York Times,
pp. D1, D4.
“ ‘Spotted hyenas live in a society just as large and complex as a baboons.’ ”
Zimmer, C. (March 4, 2008). Sociable, and smart.
The New York Times,
p. D1.
“. . . similar evolutionary forces worked independently to arrive at a similar adaptive solution . . .”
Holekamp, K. (2006). Spotted hyenas.
Current Biology
16: R944-R945.
p. 251
“. . . tool
making
as opposed to mere tool
use
. . . represented a major cognitive leap . . .”
Tattersall, I. (January 2000). Once we were not alone.
Scientific American
282(1): 57-62.
“Stone tools are thus the first evidence we have of the birth of
symbolic thought
. . .”
Tattersall, I. (January 2000). Once we were not alone.
Scientific American
282(1): 57-62.
“. . . humans must have brought musical instruments with them when they left Africa for Europe.”
Cross, I. (2006). The origins of music: Some stipulations on theory.
Music Perception
24(1): 79-82.
p. 252
“. . . workmanship [their stone tools] that displayed . . . ‘an exquisite sensitivity to the properties’ of these materials.”
Tattersall, I. (January 2000). Once we were not alone.
Scientific American
282(1): 61.
“ ‘Clearly . . . these people were
us
.’ ”
Tattersall, I. (January 2000). Once we were not alone.
Scientific American
282(1): 61.
p. 257
“. . . (my dog Shadow distinguishes several different toys by name including his ‘fuzzy man’ from his ‘Cat in the Hat’) . . . ”
My dog Isabella before him could pick out ten different items by name, including
newspaper, ball, Frisbee, bed,
and
bone.
See also: Kaminski, J., J. Call, and J. Fisher. (2004). Word-learning in a domestic dog: Evidence for fast mapping.
Science
304: 1682-1683.
“. . . but this only demonstrates their [animals’] ability to
link
a visual or acoustic stimulus with an object.”
As a well-known example, Ivan Pavlov showed that dogs can learn to associate the sound of a bell with the presentation of food. My dog associates the word
cookie
with the treats I keep in the pantry. But there are important differences between associations and a formal concept of naming, the awareness that the name and the object it refers to are two separate things. I can talk about cookies without you expecting to get one; I cannot do that with my dog, as clever as he is. That’s one of the differences between a “name” and an “association.”
p. 258
“. . . every day humans produce or hear utterances that have never before been spoken, and yet we understand them.”
I’m glossing over many important details associated with the expandable property of language. These are dealt with in Steven Pinker’s
The Language Instinct
and in the article by Hauser, Chomsky, and Fitch (see below for full references). One important concept in the discussion is the capacity for
recursion,
a cognitive operation believed by many to be unique to humans and central to language. Briefly, recursion describes the formal way in which expressions can be expanded indefinitely. It can be thought of as a set of instructions that can loop around back to the beginning, or in computer science jargon, a “routine that can call itself.” Take for example the following instructions for how to wash a dirty soup pot:
Routine for Washing a Dirty Soup Pot
3. Scrub with brush, sponge, or scouring pad until it appears to be clean.
5. Check to see if it is clean. If yes, go to step 6. If not, execute the instructions “Routine for Washing a Dirty Soup Pot.”
The “branching loop” in step 5 is what makes this recursive. It is a routine that can expand indefinitely. Human languages have sentences that can do the same thing of course, as illustrated in the main text. The notion that recursion is central to human language has been challenged by Daniel Everett. The very fact that there is a debate between the Chomskians and Everett serves to support my point that there is
not
a single unique element that humans possess that gives us language; rather, animal and human communications form a continuum and many elemental operations show up along the continuum. The fact that at least one human group lacks this operation (recursion) makes the claim untenable that it is both unique to humans and necessary for human language. For the standard view on what constitutes language, see for example: Pinker, S. (1994).
The Language Instinct.
New York: Morrow. Or see: Hauser, M. D., N. Chomsky, and W. T. Fitch. (2002). The faculty of language: What is it, who has it and how did it evolve?
Science
298: 1569-1579. For a dissenting view, see: Everett, D. L. (2005). Cultural constraints on grammar and cognition in Pirahã.
Current Anthropology
46(4): 621- 646.
p. 261
“ ‘Animals of many kinds are social . . .’ ”
Darwin, C. (1981).
The Descent of Man and Selection in Relation to Sex.
Princeton, NJ: Princeton University Press, pp. 161-163. (Original work published 1871.)
“ ‘In order that primeval men, or the apelike progenitors of man, should become social . . .’ ”
Darwin, C. (1981).
The Descent of Man and Selection in Relation to Sex.
Princeton, NJ: Princeton University Press, pp. 161-163. (Original work published 1871.)
p. 262
“In one experiment, she [Haselton] asked people to think about how much they love their partner and then try to suppress thoughts of other people they find sexually attractive.”
This description taken from Zimmer, C. (January 17, 2008). Romance is an illusion [Electronic version].
Time.
Retrieved March 10, 2008, from
http://www.time.com/time/magazine/article/0,9171,1704665,00.html
.
p. 264
“. . . European starlings can
learn
syntactic recursion.”
Gentner, T. Q., K. M. Fenn, D. Margoliash, and H. C. Nusbaum. (2006). Recursive syntactic pattern learning by songbirds.
Nature
440: 1204-1207.
“. . . white-crowned sparrows can assemble an entire song in proper sequence when exposed to only fragments of that song . . .”
Rose, G. J., F. Goller, H. J. Gritton, S. L. Plamondon, A. T. Baugh, and B. G. Cooper. (2004). Species-typical songs in white-crowned sparrows tutored with only phrase pairs.
Nature
432: 753-758.
p. 266
“It is important, when considering animal music, to distinguish between musical expression and musical experience.”
Jerison, H. (1999). Paleoneurology and the biology of music. In
The Origins of Music,
edited by N. L. Wallin, B. Merker, and S. Brown. Cambridge, MA: MIT Press, pp. 177-196.
“Evolution endowed the musical brain with a perception-production link that most mammals lack . . . We
hear
music, then
sing
it.”
Merker, B. (2006). The uneven interface between culture and biology in human music.
Music Perception
24(1): 95-98.
p. 267
“. . . most [mammals] do not have the capacity to imitate a sound they’ve heard . . .”
Merker, B. (2006). The uneven interface between culture and biology in human music.
Music Perception
24(1): 95-98.
“This vocal learning ability is believed to have come from an evolutionary modification to the basal ganglia . . .”
Patel, A. D. (2006). Musical rhythm, linguistic rhythm, and human evolution.
Music Perception
24(1): 99-104.
“. . . Brodmann area 44 . . . ”
Iacoboni, M., I. Molnar-Szakacs, V. Gallese, G. Buccino, J. C. Mazziotta, and G. Rizzolatti. (2005). Grasping the intentions of others with one’s own mirror neuron system.
Public Library of Science Biology
3(1): e79.
“. . . FOXP2 gene . . .”
Wade, N. (October 18, 2007). Neanderthals may have had gene for speech [Electronic version].
The New York Times
. Retrieved March 10, 2008, from
http://www.nytimes.com/2007/10/18/science/19speech.html?partner=rssnyt&emc=rss
.
“. . . a genetic variant in microcephalin . . .”
Gazzaniga, M. S. (2007). Are Human Brains Unique? From John Brockmans’
Edge
, April 10, 2007.
www.edge.org
.
p. 269
“. . . there are no immaterial, vitalistic, or supernatural processes involved in creating the experience we call consciousness . . .”
Bunge, M. (1980).
The Mind-Body Problem: A Psychological Approach.
New York: Pergamon.
p. 270
“. . . spontaneous intelligence.”
Johnson, S. (2001).
Emergence
:
The Connected Lives of Ants, Brains, Cities, and Software.
New York: Scribner.
“As essayist Adam Gopnik says . . .”
Gopnik, A. (2006). Death of a Fish. From
Through the Children’s Gate.
New York: Knopf, p. 258.
“. . . human music functions as an
honest signal
. . .”
There exists controversy on this point. Cognitive psychologist Jamshed Bharucha points out that a skilled performer can effectively evoke an emotion that he doesn’t feel. When a performer plays a sad piece, it’s not necessarily because he wishes to communicate his sadness. The piece may simply be on the program for that night, and the performer knows how to perform it to elicit sadness. David Byrne corroborated this in an interview with me—he doesn’t always
feel
sad when he’s singing a sad song, but he’s learned what are essentially a set of tricks or devices to evoke sadness or other emotions required for the emotional delivery of the song. Bharucha asks us to consider an evolutionary context: A man courting a woman by expressing his love to her. He can deceive her using language, i.e., convince her that he loves her even if he doesn’t, just so he can get sex. The same would be true of music. He could appear to pour his heart out to her if he is a skillful musician—even if he doesn’t feel undying love—and thereby gain access to sex. Are language and music different here? Is music an honest signal? Music may have started out as an honest signal—something difficult to fake. But a sort of arms race may have developed. Some humans would have learned how to fake the emotions in music. Through intensive training, for example, they might learn to
appear
sad or in love or happy even when they are not. Actors do the same thing with language, of course. Actors essentially lie for a living. To be successful, they have to make you think that they are someone whom they are not, and that the words they are speaking are being uttered spontaneously and on their own, even when (most of the time) those words were written by someone else ahead of time. If we accept the honest signal hypothesis, it doesn’t have to mean that music is still a foolproof honest signal, only that it once was (and perhaps still is) a
more
honest signal than language. We can speculate about why music might be better at this: Because of music’s structure and internal complexity, music typically packs much more information into a phrase than language does. This might make it more difficult to fake honesty because so many more dimensions of expression would need to be manipulated than simply the words and linguistic prosody. It’s worth noting that once expert singers learned to fool ordinary listeners, there would be increased evolutionary pressure for listeners to become more discriminating, which would lead to pressure for the singers to become more skilled. If music started out as an honest signal, with connections to all the right emotional and motivation centers in the human brain, these more (evolutionarily) recent developments may not have yet effected commensurate changes in neural wiring, or the changes may be still under way. This could account for why skillful musicians can move us to laughter and to tears: Our cognitive appraisal system
knows
that we are being “lied to,” and yet all the emotional buttons are still being pushed. The result is a deeply emotional reaction that is bound up with an aesthetic and cognitive appreciation for what is going on.