Saturday, July 29, 2006

Dennett's creatures

darwins dangerous idea
Daniel Dennett claims that generate and test is the only non question begging way to explain learning.
Learning can be viewed as self design. There doesn't appear to be a more powerful way to think about design than thinking of it as an evolution wrought by generate and test!
He elaborates further on this idea in Ch 13 Losing Our Minds to Darwin, in his book, Darwin's Dangerous Idea (the link is to a critical but thorough review by Danny Yee)

One theme is that it is language that helps make us intelligent, that distinguishes us from other species.

My initial contrarian chess players thought was: "Why not pattern recognition?" And later my evolutionary contrarian thought: "Why not tool use and tool creation?" Why does Dennett place language on a higher plane than these other human features? But he does explain his choice (later).

Dennett presents us with five hypothetical creatures arising from Darwin's evolutionary process. Each of them uses generate and test but the process becomes more sophisticated with evolution.

Darwinian creatures are created by random mutation and selected by the external environment. The best designs survive and reproduce.

Skinnerian creatures can learn by testing actions (responses) in the external environment. Favourably actions are reinforced and then tend to be repeated. Pigeons can be trained to press a bar to receive food.

Skinnerian creatures ask themselves, "What do I do next?"

Popperian creatures can preselect from possible behaviours / actions weeding out the truly stupid options before risking them in the harsh world. Dennett calls them Popperian because Popper said this design enhancement "permits our hypotheses to die in our stead". This is Dennett's enhancement of behaviourism. Popperian creatures have an inner environment that can preview and select amongst possible actions. For this to work the inner environment must contain lots of information about the outer environment and its regularities. Not only humans can do this. Mammals, birds, reptiles and fish can all presort behavioural options before acting.

Popperian creatures ask themselves, "What do I think about next?"

Gregorian creatures are named after Richard Gregory, an information theorist. Gregorian creatures import mind-tools (words) from the outer cultural environment to create an inner environment which improve both the generators and testers.

Gregorian creatures ask themselves, "How can I learn to think better about what to think about next?"

Words / language are necessary to sustain long predictive chains of thought, eg. to sustain a chain or combination of pattern recognition. This is true in chess, for example, where the player uses chess notation to assist his memory.

With respect to tools. Tools may have come before language. The evolution of the hand with an opposable thumb is an early "inbuilt" tool, in combination with erect posture. It has been shown that those things happened before the increase in brain size. See Engels, Gould. This observation, however, does not refute Dennett's proposition of the primacy of language in contributing to intelligence. Tools can be a fundamental building block and language still primary.

Learning from mistakes is an important and hard to learn part of this process. To learn from mistakes one has to be able to contemplate them and language / communication assists that process. For example, by being told by someone else you have made a mistake.

Finally, we have Scientific creatures which is an organised process of making and learning from mistakes in public, of getting others to assist in the recognition and correction of mistakes.

The value of Dennett's account is:
  • he traces a very plausible evolutionary sequence for the development of the mind
  • he extends the core correct concept of behaviourism (generate and test) into the inner environment
  • he has a thought out opinion about the importance of language in human intelligence and its relation to tool use and tool creation (the bits about pattern recognition have been added in by me)

After thoughts / links:
Review of Dennett's Kinds of Minds, points 9,10 and 11 are great:
... we use language to author ourselves, assisted by many co-authors as we grow up
The Role of Language in Intelligence: lecture by Dennett

Tower of generate-and-test comprehensive write up of Dennett's ideas

1 comment:

Anonymous said...

Bet you didn't expect a comment 9 years later... but great summary. I'm a Tufts student, and seemed smart in a class with the man himself today. Thanks!