Is this the sort of thing that's in the scope of JREF's challenge? It says "psychic, supernatural, or paranormal ability". If this experiment does show a result from manipulating mental age with a throwback environment, we wouldn't assume that result derived from a paranormal cause. It would be a new psychosomatic effect where the mind can affect the body, but it would be through normal biological and chemical means, not the supernatural evidence JREF is looking for.