The rule could be anything, as funny or as serious as you want. The universe will progress in a similar way that it has up until this point, unless your changed rule prevented it from doing so.
Some examples might be:
- The invention of currency is not allowed.
- Iron is slightly less stable.
- The Ancient Greeks are able to cultivate Silphium, which does not go extinct now.
CEOs and similar psychopaths don’t, though.
(Though those already tend to have the intelligence of a particularly stupid dog anyway, so I don’t really see how this would change anything.)
I thought the thing about psychopaths is not that they don’t have empathy or that it’s something that’s completely bizarre and alien to them, but rather that they have a switch where they can turn it off.
Like most of us would recoil in horror at watching a video of somebody being beheaded on the internet and many of us have had that unfortunate experience, but a psychopath has the ability to not feel anything at all about it if they don’t want to.