Wei_Dai comments on [LINK] AmA by computational neuroscientists behind 'the world's largest functional brain model' - Less Wrong

7 Post author: michaelcurzi 03 December 2012 07:35PM

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Comment author: Wei_Dai 04 December 2012 11:26:52PM *  1 point [-]

According to my understanding, Spaun is only able to shift between a fixed set of tasks, and according to a fixed algorithm (if the first two inputs are "A1", route the information one way so that it ends up doing one task, and if the first inputs are "A2", route the information another way, etc.) that was manually designed. You haven't explained yet (or emulated) how human brains are able to switch fluidly between an ever changing set of possibe tasks, and without having to be prompted by specific codes such as "A1" and "A2".

If my understanding is correct, I think a clearer and fairer description of your accomplishment might be that you've demonstrated task shifting "on a (simulated) neural substrate that is structually similar to the human brain", rather than task shifting "just like the human brain".

Comment author: tcstewar 05 December 2012 12:03:45AM 1 point [-]

Yup, I'd say that's a fair way of expressing it, although I think we take "neural substrate that is structurally similar to the human brain" much more seriously than other people that use phrases like that. It's a similar enough substrate that if fixes a lot of our parameter values for us, leaving us less open to "fiddle with parameters until it works".

We've also tried to make sure to highlight that it can't learn new tasks, so it's not able to work in the fluid domains people do. It also doesn't have any intrinsic motivation to do that switching.

Interestingly, there are starting to be good non-neural theories of human task switching (e.g. [http://act-r.psy.cmu.edu/publications/pubinfo.php?id=831] ). These are exactly the sorts of theories we want to take a close look at and see how they could be realistically implemented in spiking neurons.