In nature, this refers to prey animals not being able to recognize predators. When wolves were reintroduced to Yellow Stone the elk were not able at first to recognize them as a danger. Animals isolated on islands, are famous for this syndrome and often are not able to change fast enough, for example, the flightless pigeon, the Dodo, which sailors could just walk up to and hit on the head.
We are all raised to be naive prey of psychopaths. Everyone is told the fairytale that we are all brothers and sisters under the skin. But what if that is not so? And it is not. Believe me, psychopaths believe we are all idiots for not recognizing them.
On top of that, the human female starts out as genetically inclined to be naive prey to psychopaths. Male psychopaths have evolved to evoke genetically determined instincts (mothering and caring-of-a-child instincts) in women, I believe. Life can teach them otherwise, as attested in the survivor blogs. However, all men need to be aware of the female propensity to be naive regarding psychopaths, it might prevent traumatic shock. The truth is, you can’t save Weena.
From a later comment:
Here’s an account of early firearm buffalo hunts. I can’t vouch for its historical/biological accuracy, but it does convey a message. It goes like this, 1) the buffalo of the time didn’t and couldn’t recognize guns and gunshots as being dangerous (naive prey syndrome), 2) buffalo herds follow a dominant female, with a pecking order. So the hunter would lie down in some kind of blind, maybe just behind a log. Experienced hunters would know how to recognize the dominant female. So he would target that one. The others couldn’t fathom what had happened and couldn’t act on their own without a herd leader. Then the next in line dominant female would step up to be herd leader. Then she was shot, and the process continued over and over again, with the herd never panicking. The hunter wouldn’t ever have to move. “HEY, what happened to Martha? And Ethel? What the hay?? Dunno, just keep eating that grass, munch, munch, munch. Wow, that’s some delicious grass!” https://pathwhisperer.info/2018/05/07/annoying-neighborhood-psychopaths-and-anomalous-occurrences/#comment-139279
. . . munch, munch, . . ., munch, munch, munch.