The Brain–Computer Metaphor

 

This is a link to Chris Chatham at scienceblogs.com.

Although the brain-computer metaphor has served cognitive psychology well, research in cognitive neuroscience has revealed many important differences between brains and computers. Appreciating these differences may be crucial to understanding the mechanisms of neural information processing, and ultimately for the creation of artificial intelligence. Below, I review the most important of these differences (and the consequences to cognitive psychology of failing to recognize them): similar ground is covered in this excellent (though lengthy) lecture.

10 Important Differences Between Brains and Computers.

  • Difference # 1: Brains are analogue; computers are digital
  • Difference # 2: The brain uses content-addressable memory
  • Difference # 3: The brain is a massively parallel machine; computers are modular and serial
  • Difference # 4: Processing speed is not fixed in the brain; there is no system clock
  • Difference # 5: Short-term memory is not like RAM
  • Difference # 6: No hardware/software distinction can be made with respect to the brain or mind
  • Difference # 7: Synapses are far more complex than electrical logic gates
  • Difference #8: Unlike computers, processing and memory are performed by the same components in the brain
  • Difference # 9: The brain is a self-organizing system
  • Difference # 10: Brains have bodies

All these are valid points and I won’t argue with them. The insights were dearly bought during the fifty years of toil that separate us from the pioneers. Not a single difference from this list was lost on them, however. At the height of the day, in the golden age of cybernetics, they seemed unimportant. We assign importance to them now because so many attempts at the construction of electrical brains have failed. This is a very weak argument.

Recent research shows that memories may be erased during recall:

Using a combination of protein engineering and organic chemical synthesis, the researchers manipulated levels of a key enzyme called alpha calcium/ calmodulin-dependent protein kinase II (αCaMKII) at specified times in the mouse brain, and found that transiently increasing the level of the enzyme just before recall of a memory led to its selective erasure.

This looks suspiciously like static RAM. If the address is applied, tampering may change memory contents.

 Date Posted: 18 Aug 2009 @ 09 30 PM
Last Modified: 27 Apr 2013 @ 05 42 PM
Posted By: Hardy
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