I came across the following on another forum: This, of course, is the same issue that arises with eye witness testimony in court. It's worth keeping in mind when reading such things as 2nd hand hearsay in the NT epistles.
I don't know if it applies that well to Paul. It depends on your viewpoint as to if he was truly recalling real memories and trying to piece it together, or if he was taking a real person's life (or not at all real, but some rumored existence) and constructing his own belief system around that image. In other words, was Paul remembering, or making a religion? The study sounds interesting in itself though...more proof that the human brain tries to take what info it gets and piece it together the best it can, sometimes misleadingly.
Of course he wasn't "remembering". The closest he ever got to the purported life of Jesus was, at best, some hallucinatory experience on the road to Damascus. This is precisely why I refer to the testimony found in Luke, Paul, and the Deuteropaulines as "2nd hand hearsay".