y refusing to act personally and directly to save lives, people may be demonstrating what Greene calls "the byproduct of a Stone Age neurological structure" that programs us to avoid killing. This is why a choice sometimes feels good--like an absolute truth--when it may be morally wrong.
"Stone Age" is a biased term. Comparing flicking a switch to kill one person versus pushing one person involves different motor processes, motor skills, preparatory planning for the motor processes, etc. There's a lot more to the difference than "Stone Age programming" that avoids active killing. In any case these decisions are hardly useful demonstrations of empathy since it exists in spades for all the parties in all the situations. The only difference in my opinion is variations in utilitarian logic.
46 million dead...
That's why his peer-reviewed scientific journal articles are more careful in their wording. You should stick to them if imprecise vernacular bothers you.
Comparing flicking a switch to kill one person versus pushing one person involves different motor processes, motor skills, preparatory planning for the motor processes, etc.
That's not why the moral decision is different and they have other tests. You are getting hung up on the particulars looking for an "out" that proves the conclusions are wrong rather than looking at all the evidence that they are right.
There's a lot more to the difference than "Stone Age programming" that avoids active killing.
And what differences are those? From a purely utilitarian standpoint and an entirely objective standpoint, the trade of one life for five is identical whether you passively kill the one person or actively kill them. Why are they morally different?
In any case these decisions are hardly useful demonstrations of empathy since it exists in spades for all the parties in all the situations. The only difference in my opinion is variations in utilitarian logic.
You seem to think that empathy is binary. Part of the point of the research is that it's not. It comes in degrees and the degree at which one feels empathy for one victim or another and other emotional factors balance by degree against utilitarian considerations that may be strong or weak.
During the famines caused by Mao's "Great Leap Forward", Chinese parents created the practice of "yi zi er shi" ("Trade kids, then eat"). The reason for this practice is that no parent wanted to eat their own children but they could bring themselves to eat a neighbor's child, thus they'd swap kids so that they wouldn't have to kill and eat their own. The empathic shift from your own familiar child to someone else's less familiar child was enough for them to tilt the balance of their moral calculus from empathy (to prefer death over eating your own kids) to utilitarianism (to prefer eating a neighbor's kid over dying). It wasn't that these parent's didn't have any empathy (they didn't want to eat their own kids, nor likely their neighbor's kids, either) but the utilitarian pressure for cannibalism (the alternative being starvation) was so strong that it could overcome the empathy for a generic child even where it couldn't overcome their empathy for their own child. And even then, their empathy for their own child was less when their death was passive (at the hands of a neighbor) rather than active (killing them with their own hands).
There are examples like this all around us and throughout history. You can laugh at Greene's use of the term "Stone Age" all you want, but there is an empathic difference between strangers, friends, and family, those we can see and those we can't, and whether we actively do a wrong to someone else or passively let it happen. And it has to be that way. If I felt as much empathy for every human on Earth as I feel for my family or even friends, I'd be unable to function from grief, given the horrible ways that people die every day. I can't care about the whole world with the care I give my family. But that's also why no person should be able to make subjective moral decisions. The result easily becomes some variant of "yi zi er shi". Would I sacrifice the life os some faceless Chinese political prisoner to get an organ my wife needed to live? I'd like to think I wouldn't but it's not an easy decision nor a clear one that you'll get concensus on.