Perceptual Learning

Perception is a form of action. It is a skill set that is incredibly useful for gathering information about the environment so that we can act in various ways. Some aspects of our perception are inborn, such as the ability to perceive faces as infants. Others are learned. In this post I want to discuss a famous anthropological case that clearly illustrates the reality of perceptual learning.

In the late 1950s and early 1960s, Colin Turnbull spent time in the Ituri Forest in Congo studying the BaMbuti Pygmies. He spent the majority of his time observing their behavior as it occurred in its natural setting. He had a young(22 years old) Pygmy assistant named Kenge who acted as a guide. On one particular excursion in between villages, Turnbull and Kenge came to the edge of a hill that had been cleared of trees. This clearing offered a view of the distant Ruwenzori Mountains. Normally, the Ituri forest is extremely thick and such clearings are rare. Because of this, Kenge had never experienced a view over such vast distances. He asked if the mountains were hills or clouds. Turnball offered to drive over to the mountain to see them more closely.

On the drive over, it began raining and the visibility was reduced. Upon arriving to the foot of the mountain, Kenge was amazed at their size. He didn’t know what to make of their snowcaps. As they were leaving, a herd of buffalo grazing on the plain a couple of miles away was visible. Kenge asked Turnbull what kind of insects they were! Turnbull tried to inform Kenge that the buffalo were much bigger up close, but because Kenge had never learned the perceptual skill of size constancy, he was skeptical of such claims. Turnbull, of course, drove Kenge to the buffalos. As they were driving, the optic array of the buffalo became larger and larger to Kenge, and he asked Turnbull what sort of witchcraft was at work to make the buffalo grow in size. Over the next day or so, Kenge quickly learned the skill of perceptual size constancy and no longer made such optical errors.

This fascinating anthropological tale vividly illustrates how important exposure to a wide variety of different environments is crucial to developing an adaptable perceptual system. Kenge had grown up in the dense forest and had never been exposed to optical arrays of the environment that offered information about such great distances. This lack of distance information shaped the development of his brain in such a way as to make it quite shocking when he was finally exposed to such optical information 22 years into his life. It is a testament to the plasticity of the brain that he was able to adapt so quickly and illustrates how readily our perceptual systems learn when exposed to new environmental circumstances.



Filed under Philosophy, Psychology

2 responses to “Perceptual Learning

  1. There is a missing element in most theories of perception, since
    perception = subject + object, The missing element is the subject.
    Daniel Dennett has spilled a lot of ink over what the subject is not, but
    hasn’t come up with a definition of the subject. Dennett is a materialist, a philosophy in which the subject is at best only implied. Its origin goes back to the Enlightenment, in which anything nonphysical (the self) was done away with and replaced by the brain, which is a piece of meat with the self operating it. The self plays the material brain like a violin. I have escaped from the dogmas of materialism by switching to the Idealism of Leibniz. Imho this is the only possible philosophy which truly gives us understanding of what the self and consciousness is. It is us in the first person, not the third person as in materialism.

    Dr. Roger B Clough NIST (ret.) [1/1/2000]
    See my Leibniz site at

  2. Kant’s disproof of materialism and empiricism
    Materialists argue that in essence we are no more than our bodies.
    Empiricists such as Hume ruled out the possible influence of anything transcendental
    in our perception of objects.
    But that position was disproven by Kant, for example in his transcdendent deduction of
    the role of the self in perception
    in which cognitive science and philosophers such as Dennett and Chalmers
    seems to have overlooked the critical importance of the transcendental.
    As a result, Kant gave this argument against materialism and empiricism:

    “Kant  proposed  a  “Copernican  Revolution-in-reverse”,  saying  that:

    Up  to  now  it  has  been  assumed  that  all  our  cognition  must  conform  to  the 
    objects [materialism and positivism] but  …  let  us  once  try  whether  we  do  not  get  farther  with  the  problems  of 
    metaphysics  by  assuming  that  the  objects  must  conform  to  our  cognition[transcendental idealism].”
    Dr.  Roger  B  Clough  NIST  (ret.)  [1/1/2000]
    See  my  Leibniz  site  at

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