The Newell Test

1. The Newell Test You might say this is a soonest, vacuum airport - an unwilling calculation of sorts. That would be a really weird thing to say, though.

2. Connectionism

3. Grading • Earlier Version used grades • I had a problem with this • If an A is human, where does any model really belong • New rankings are less

4. Flexible Behavior • Computationally Universal • But some things are easier than others

5. Real Time • 2 Meanings • Model makes accurate predictions of time human processes and learning take • Slow learning in connectionist networks • Model does so in a timely manner

6. Adaptive • Behaviors serve needs • Globally is behavior optimal • Locally, are individual process useful

7. Vast Knowledge • Lots of Data • Not at all well understood how the brain does this in such a massive fashion • General mechanism are a bit clearer

8. Dynamic • Copes with changes

9. Knowledge Integration • Functionality of intellectual combination • I’d like to call it Representation and Combination

10. Newell’s Quote • “Symbols provide distal access to knowledge-bearing structures that are located physically elsewhere within the system. The requirement for distal access is a constraint on computing systems that arises from action always being physically local, coupled with only a finite amount of knowledge being encodable within a finite volume of space, coupled with the human mind’s containing vast amounts of knowledge. Hence encoded knowledge must be spread out in space, whence it must be continually transported from where it is stored to where processing requires it. Symbols are the means that accomplish the required distal access.” (Newell, 1990, p. 427)

11. Dictionary • symbolnoun [C] a sign, shape or object which is used to represent something else 

12. What is a Symbol • Hot Debate in Cognitive Psychology • Most with an opinion in the class believed the brain could not contain symbols • I found this astounding until I found out they were using Newell’s definition • Does a spring symbolize the pressure put upon it? • Many think symbols could not exist in the brain by Newell's definition • However, they will all agree the brain represents the data…

13. Natural Language • Can it talk • Connectionism tries to build the capability from scratch • ACT-R relies on symbolic interaction to explain linguistic results

14. Consciousness • Can it inspect it’s buffers? • Worse/worse • I disagree and think ACT-R is better than worse • In my opinion consciousness is the parallel matching of all productions with buffer contents

15. Learning • Squire • Episodic • Semantic • Skills • Priming • Conditioning • Learning is in some ways fundamental to cognitive psychology so has been a big focus

16. Development • Does it grow • ACT-R is better than worse I think • Example in the paper • Bootstrapping problem • Everything is hand coded just about

17. Evolution • Is it susceptible to selection and variation

18. Brain • How do the neurons do it?

19. Spur to Progress • Attack of the killer bees is thwarted • Makes reflection on the strengths of other work better

20. Interesting compromise • Theories coming closer • Thad Polk’s Idea (one of Newell’s Grad Students) • Production rule compiler • Transforms production rules into networks

21. Joe • Overall I found the article to be fairly clear and interesting. However, I was a little fuzzy on the topic of ACT-RN. I'm not sure I understand how the chunks are actually represented, and how the headers interact with the chunks.

22. ACT-RN Declarative memories 3 Winner take all Network retrieval chunks 1 4 2 slots 5 header Represents chunk name Figure 1: Type Memories

23. Ian • I'm going to work with this analogy: that an assembler is to a processor as activations and connection strengths are to neurons, and that c is to assembler as act-r is to activations and connection strengths, except there isn't the same layer of abstraction between c and asm.

24. OK

25. Er, it turns out I won't reference that last sentence at all. Here's the question I have now: how does act-r account for individual differences in cognition? It is nice that the averages of human data correspond to act-r data, but it seems that a fundamental layer of paramaterization must take place to account for individual differences.

26. Good question. ACT-R actually has a number of parameters that might account for individual differences including W, s, d, tau, and others less commonly changed such as the 50 ms cycle time…

27. The general nature of act-r, with its emphasis on non-parameterization, also leads me to a related question. It seems that much of the body of knowledge on neuropsychology has come from studies of partially impaired animals. Is there any way act-r can account for the particular ways in which an individual might deviate from the averaging of humans.

28. We haven’t started to talk about all the parameters yet. And yes, these parameters might account for neuropsychological deficits

29. One more, actually. Does anything like act-r exist for animals? As an assembler is to a processor, another assembler is to another processor, and it seems similar principles may apply.

30. Sure, but I’m not aware any ACT-R researchers or anyone has used production rule modeling for animals… • John?

31. Dana • The concept of setting criteria to which all theories of cognition should aspire to fulfill seems to be an advantageous goal that would provide both a way to compare extremely different theories and to assess their respective strengths and weaknesses. However several questions about the validity of the whole process must be overcome. Since the criteria originated from a symbolic view, are they biased from the beginning? Also, will it be possible to convince everyone that these criteria are the best criteria to evaluate cognitive theories? No matter how well defined the rules of the game, if no one wants to play, it doesn't matter.

32. Sure, they are biased, but I’d be happy to hear their critereon. • In general, the idea of a unified architecture is an idea that stems from production system modeling. Many do not necessarily agree that the idea is profitable, necessary, etc… • I get the feeling many connectionists just use connectionism as a tool and aren’t interested in this unified archtecture concept… Some however, would agree that many of these criterea are important

33. Jane • why does connectionism do better on natural languages than actr?

34. Because it doesn’t need to be engineered to pick up on statistics in the environment… It does so automatically…

35. Matt • "Among other domains for which ACT-R seems to be lacking adequate mechanisms are... emotion and motivation" (p. 20) What would such a model look like? Some theories of learning emphasise motivation. How would it interact with learning mechanisms in ACT-R?

36. Well perhaps motivations would be kinda like productions that fired when certain drive or emotional states were active

37. A general curiosity of mine, which led me to learn more about ACT-R: "Sometimes the suspicion is stated that ACT-R is a general computational system that can be programmed to do anything." (p. 19) The four limitations described help me to see that this isn't true. However, I'd like to know what makes ACT-R especially suited to creating accurate cognitive models.

38. Hmm… What exactly do you mean? It is suited for cognitive modeling because that is what it was designed to do from the very start

39. Inspired by the discussion on development (p. 26): How would along-term "metamodel," encompassing possibly long term memory, or a daily juggling of various priorities interact with ACT-R?

40. Once we cover the production competition I think this will be imaginable… I think perhaps high-level priorities might be juggled in a similar fashion according to their “emotional” utility • This sort of high level modeling would be fantastically complex

41. David • The question that still sticks with me is how the Newell test is intended to solve the listed problems Newell saw in the field, if that is in fact the intention. For example, none of the criteria address the stability or diversity of theories.

42. I think the idea is that by having a unified model stability is fostered and diversity is unified.