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← Evolution’s great mystery: Language - Michael Corballis

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Showing Revision 3 created 08/11/2020 by lauren mcalpine .

  1. In the 1980s, a bonobo named Kanzi
  2. learned to communicate with humans
    to an unprecedented extent—
  3. not through speech or gestures,
  4. but using a keyboard of abstract symbols
    representing objects and actions.
  5. By pointing to several of these in order,
    he created sequences to make requests,
  6. answer verbal questions
    from human researchers,
  7. and refer to objects
    that weren’t physically present.
  8. Kanzi’s exploits ignited immediate
    controversy over one question:

  9. had Kanzi learned language?
  10. What we call language is something
    more specific than communication.

  11. Language is about sharing
    what’s in our minds:
  12. stories, opinions, questions,
    the past or future,
  13. imagined times or places, ideas.
  14. It is fundamentally open-ended,
  15. and can be used to say
    an unlimited number of things.
  16. Many researchers are convinced
    that only humans have language,

  17. that the calls and gestures other species
    use to communicate are not language.
  18. Each of these calls and gestures generally
    corresponds to a specific message,
  19. for a limited total number of messages
  20. that aren’t combined
    into more complex ideas.
  21. For example, a monkey species
    might have a specific warning call
  22. that corresponds to a particular predator,
    like a snake—
  23. but with language, there are countless
    ways to say “watch out for the snake.”
  24. So far no animal communication seems
    to have the open-endedness
  25. of human language.
  26. We don’t know for sure what’s going
    on in animals’ heads,
  27. and it's possible this definition
    of language,
  28. or our ways of measuring it,
    don’t apply to them.
  29. But as far as we know,
    only humans have language.
  30. And while humans speak
    around 7,000 distinct languages,
  31. any child can learn any language,
  32. indicating that the biological machinery
    underlying language
  33. is common to all of us.
  34. So what does language mean for humanity?

  35. What does it allow us to do,
    and how did we come to have it?
  36. Exactly when we acquired this capacity
    is still an open question.

  37. Chimps and bonobos
    are our closest living relatives,
  38. but the lineage leading to humans
    split from the other great apes
  39. more than four million years ago.
  40. In between, there were many species—
    all of them now extinct,

  41. which makes it very difficult to know
    if they had language or anything like it.
  42. Great apes give one potential clue
    to the origins of language, though:
  43. it may have started as gesture
    rather than speech.
  44. Great apes gesture to each other
    in the wild much more freely
  45. than they vocalize.
  46. Language may have begun to take shape
    during the Pleistocene,

  47. 2 to 3 million years ago,
    with the emergence of the genus Homo
  48. that eventually gave rise
    to our own species, homo sapiens.
  49. Brain size tripled, and bipedalism
    freed the hands for communication.
  50. There may have been a transition
    from gestural communication
  51. to gestural language—
  52. from pointing to objects
    and pantomiming actions—
  53. to more efficient, abstract signing.
  54. The abstraction of gestural communication
    would have removed the need for visuals,

  55. setting the stage for a transition
    to spoken language.
  56. That transition would have
    likely come later, though.
  57. Articulate speech depends
    on a vocal tract of a particular shape.
  58. Even our closest ancestors,
    the Neanderthals and Denisovans,
  59. had vocal tracts that were not optimal,
  60. though they likely had
    some vocal capacity,
  61. and possibly even language.
  62. Only in humans is the vocal tract optimal.
  63. Spoken words free the hands for activities
    such as tool use and transport.
  64. So it may have been
    the emergence of speech,
  65. not of language itself, that led
    to the dominance of our species.
  66. Language is so intimately tied to complex
    thought, perception, and motor functions

  67. that it’s difficult to untangle
    its biological origins.
  68. Some of the biggest mysteries remain:
  69. to what extent did language
    as a capacity shape humanity,
  70. and to what extent did humanity
    shape language?
  71. What came first, the vast number
    of possible scenarios we can envisage,
  72. or our ability to share them?