http://www.inf.fu-berlin.de/lehre/pmo/eng/Sagan-Baloney.pdf
https://rationalwiki.org/wiki/The_Fine_Art_of_Baloney_Detect...
http://www.inf.fu-berlin.de/lehre/pmo/eng/Sagan-Baloney.pdf
https://rationalwiki.org/wiki/The_Fine_Art_of_Baloney_Detect...
I won't assert the truth of it, and I can think of a couple plausible vectors that don't involve consciousness surviving death and into another body (however unlikely they might be), but if it's compelling enough for the author of The Demon Haunted World to suggest it deserves "serious study", I'm the last person in the world to gainsay him.
I think he is not asking a "serious study" because he think it's real, but because at some point we must make the experiments to verify or falsify the theories. (I think that the problem is that there is finite time and finite money for the experiments, so we must select only some of them.)
I have no idea how to go about falsifying that, though. You'd at a minimum have to strictly monitor the information flow into a child's environment, probably from birth, to control for any other vectors for verifiable details. All in the hopes that some of the study population's children will mention something you can confirm they didn't overhear, or whatever, which turns out to comport with the life of someone who's passed. That's perhaps a tough sell to the ethics committee.