But, I can see that it would be more likely, statistically, and here is why.
The test was to "teach that there is no free will." If the result was a statistically noticeable change in behavior, doesn't that imply that there is free will? I suggested that people would do whatever they selfishly want if they believe they have no accountability (and I offer an example of that below, but that is not to say that every person will act that way, only that there will a statistically notiecable change...or at least that is the hypothesis).
To me, free will is self evident reality. Or, I am programmed to perceive it as such. Either way, it seems like an unimportant issue to me, and I choose to believe in it regardless, for the following reasons:
(1) If there is no free will, then nothing really matters, as I have no choice, and my desires or training will change nothing.
(2) (a) If there is free will, then it is best to believe that there is free will because it is true, and because altruistic behavior is more likely to be encouraged. But,
(2) (b) If there is free will, and people believe there is no free will, then non-altruistic, statistically noticeable purely selfish behavior may be more likely because those people will incorrectly believe they have no personal accountability because they have no choice.
It may turn out that evolution developed altruistic societal rules (e.g., civilized behavior) as a great way to encourage successful passing down of genes...but if one convinces oneself that they don't have to pay attention to those societal rules (because, after all, they have no choice in the matter), then they may act on a selfish individualistic basis, and society will suffer as a result.
You said, "If the being known as Ned on this forum is made up of atoms that amount to what we consider a "good person" then that person will make good decisions and behave as a good person would regardless of whether they have a real choice in the matter." I'm inclined to agree. But, I have a good friend who confided over drinks one night that if he believed there was no God, then there would nothing to stop him from killing someone if he felt like it. His belief in God was the only thing that kept him from contemplating evil acts. I was actually quite shocked by this at the time, thinking what a precarious thing (mere faith) kept him from feeling remorse for stealing from me. If you told someone like that that they had no free will, and therefore there was no Christian God monitoring his will's performance, and if you consider that there might be people like that all around the world, then certainly bad things could happen if you removed accountability.
Personally, I think altruism is its own reward, at least in part. When I became an atheist, and then reverted to Catholicism, no one could see a difference in my behavior, because my inter-human morality remained the same the entire time, and only my human-to-God morality changed. But, apparently others don't think like I do, and need a God to keep them acting in a good way.
You said, "I maintain agnosticism as my belief system, but a book called Many Lives, Many Masters was helpful to me. The concept that we are here to gain wisdom and that this life is about learning is comforting and strangely makes a lot of sense. And the concept works in a simulated multiverse with people under the illusion that they have free will." Do you think it makes sense to you because you didn't have any other choice but for it to make sense, and your success in following that guideline (to gain wisdom) is predetermined, so you can't take any pride or comfort in it, other than the pride and comfort you were fore-ordained to take in it?