Magnetoreception: why is conditioning so seldom successful?

Conditioning is a highly successful method for analyzing the sensory capacities of animals. With magnetic stimuli, however, it does not seem to work: negative results by far outnumber the positive ones. This is true for cardiac and operant conditioning as well as for directional training. The reasons for these failures are largely unclear. They may stem from the function of the magnetic field as orientation cue and from the fact that the magnetic field never undergoes a rapid change in nature, which means that animals might not be adapted to respond to such changes. Moreover, since the magnetic field contains directional information, animals might evade the problems arising from self-produced movements by calling on magnetic information only when needed for orientation. In view of this, conditioning does not appear to be a suitable technique for testing magnetic sensitivity.