Paper about sensing magnetic fields?
I vaguely remember seeing a paper floating somewhere, part of which involves testing someone with magnet implant in their finger to see if they can sense magnetic fields or not (there was a graph that shows that the number of times that the subject gets it right reaches almost 100%). I can't seem to find it anymore (especially since I've forgotten what the study was actually about and who wrote it). Does that ring any bells for anyone here? Thanks.