Ha! I knew someone would complain about that.
First of all, Eric is correct: the main point of the story - beyond a nice,
illustrative example of how a GA works - is the need to properly define a
fitness function. In the case of individual chickens, the fitness function
was ill-defined and
Wow ... it is a small world sometimes. We started talking about Genetic
Algorithms on a different thread. So of course I was thinking about
Dr. Michalewicz, who taught a class in GA that I took a few years ago, and
(literally) wrote the book on the subject.
And then the very next thread I read
It's not a good example as an illustration of GA because (1) the selection
mechanism to move from one generation to the next is essentially select the
best and shake it up. At best you might call that elitism plus mutation. But
it is not representative of GA. (2) it has no explicit representation
Selecting for productive coops rather than productive hens might reject highly
productive, highly aggressive hens in favor of somewhat less productive,
considerably less aggressive hens who would leave their coop-mates in peace
(and therefore able to produce more eggs). Such hens need not have
Well, in regards to (1), yes, I would guess elitism + mutation is a good
description. However, I believe that is enough to qualify as a GA. As I
recall, some GA practitioners believe mutation is best, some believe
crossover is best, and some feel you should have both, or decide based on
the
Tory --
It was mostly that the stages seem to be empirically valid - I can recall many
instances where I've been in a team or relationship that had the excitement and
novelty of coming together, the inevitable misunderstandings/arguments about
how to proceed, a reconciliation and synthesis
Everybody,
Why do the best conversations happen when I am totally unable to pay proper
attention to them!?
Somebody help me out here. A genetic algorithm is a PROCEDURE, right? So you
run the procedure on a computer. Is it possible to implement that same
procedure on crates of chickens.
John,
Thanks. I agree. In fact, I would argue that ANY attempt to squeeze
spiritual juice from this particular example blunts it scientific edge.
To mix a metaphor.
N
Nicholas S. Thompson
Emeritus Professor of Psychology and Ethology,
Clark University (nthomp...@clarku.edu)
I have been here before. This is the point in the conversation where Roger
Critchlow explains to me what the hell is going or or, i die. Roger?
Is there a confusion here concerning what is the analogue of the individual in
the genetic algorithm?
Nick
Nicholas S. Thompson
Emeritus
I am reminded of two conflicting reports I got from two friends about an
attempt to evolve a sorting program. One friend reported that it was
discouraging. The evolved programs never were reliable and they took all kinds
of time and had many superfluous features. The only way to actually get
I've had both experiences. The successful version had a couple of
advantages. It had more useful primitives and a more useful fitness
function. I don't remember the details, but a primitive that says swap
adjacent cells if one is less that the other helps a lot! A fitness
function that counts the
Thanks Russ. depending on the primitives chosen, this could be more in line
with the pessimistic account. Putting in the swapping primitive seems like
aiming for the simple sort which keeps on swapping until it can't be done
anymore.
Do you know of any evolutionary process which produced a
How is selective breeding / clustering to optimise particular traits in
chickens any different from endogamous human clusters / societies? In India
for eg. the endgamous caste and sub-caste systems have been in place for
millenia to ensure genetic optimisation and perpetuation of a few
desirable
Perhaps if I understood the computer side of this conversation better I
wouldn't have the feeling that the chicken example is being misunderstood. But
I dont and I do (respectively). It should be remembered that no chickens were
selected during the conduct of this experiment; only crates.
Russ Abbott wrote:
In a system like this though, you always have to start with some
primitives. It's really matter of where you can get from the
primitives and whether there is a steadily uphill (in terms of
fitness) path for getting there.
That's a question of how diversity is maintained in
Exactly. Although this was not (as far as I know) part of the experiment,
one could imagine a similar experiment on groups with more structure, e.g.,
baseball teams. It's the team that wins the most games (or the most
important games) that reproduces. That team probably has pretty good players
Hywel White et al re 2010 and1995 neutrino mass findings at Los Alamos
Neutrino Detector: Rich Murray 2010.07.10
I have been privileged for over 2 years to warmly appreciate many explorers
with sophisticated views at Friday Morning Group.
As a layman in all areas, I notice that science
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