Monthly Archives: November 2007

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.


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Brainbow: Neural technicolor

I just had to post this link to a multimedia gallery featuring a fluorescent tracing technique for staining neural tissue discovered by a team at Harvard.

Too cool.

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The consciousness of Self involves a stream of thought, each part of which as ‘I’ can 1) remember those which went before, and know the things they knew; and 2) emphasize and care paramountly for certain ones among them as ‘me‘ and appropriate to these the rest. The nucleus of the ‘me‘ is always the bodily existence felt to be present at the time.
-William James, Principles of Psychology

Before, I have discussed the self, but in this post I want to ruminate on the consciousness of the self. What does it mean to be conscious of your own self? Doesn’t this concept first need to define the self in order for it to be coherent? Since we started with William James, we might as well use his phenomenal analysis of what the Self is and run with it:

In its widest possible sense, however, a man’s Self is the sum total of all that he CAN call his, not only his body and his psychic powers, but his clothes and his house, his wife and children, his ancestors and friends, his reputation and works, his lands and horses, and yacht and bank-account.

I really like this broad definition of the self, because it reflects the increasingly influential work of Andy Clark and his concept of the extended mind. Under this conception, the mind is can be said to not just be the internal processes going on in the brain, but also, the external processes useful for cognition. Thus, the writing pad that you furiously scribble your thoughts on would rightfully be considered as part of your mind. This concept isn’t supposed to reflect any fancy metaphysical notions, but rather, it just views the mind as being coupled to the environment. When you are driving your car, your self diffuses into the various driving apparatuses and your mind becomes coupled with the environment in a very real way. You feel in tune with the car as you subtlety perceive the vibrations of the road through the steering wheel. Your mind is extended into the environment.

Going back to the James, the self can be divided into three parts:
1. Its constituents, which include the material, social, and spiritual aspects of the self. The material and social aspects of the self are mostly self-explanatory and explained by the above quote. By spiritual, James merely means the “inner or subjective being”.
2. The feelings and emotions the constituents arouse (Self-feelings)
3. The actions to which the constituients prompt(Self-seeking and self-preserving behaviors)

Furthermore, these constituents aggregate into an “empirical self”, which consists of all things objectively known to be “yours”(Your house, your loved ones, your body, etc). The “I” which knowns these objective aggregations can be considered as a Thought, which is different from moment to moment, with the present moment including or appropriating the previous moments. James concludes that if this stream-of-thought can be said to exist, which most psychologists wouldn’t deny, then the Thought itself is the thinker. By this, he means that it is not necessary to formulate some transcendental or spiritual soul to be the possessor of the various thoughts, because the momentary Thought by itself, by virtue of it appropriating the previous moments, can be said to be the “I”, or thinker.

This is but a brief summary of James ideas on the self and consciousness, hopefully giving you an abbreviated picture of the depth of his thinking. Because of such piercing insights into the structure of the mind, William James was a pioneer philosopher and psychologist in his time and to this day remains relevant and influential to many modern schools of thought, including the extended mind philosophy of Clark that was mentioned. James’ insights into how the self bleeds into the external environment is a philosophical precursor to the most current movements going on in philosophy today,  a testament of to the clarity of his insights.

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