Fig. 2. Top view of a coil system and magnetic vectors. Both training and testing took place in the centre of a four-coil system that produced magnetic fields that differed in alignment by 90°. The two fields had a horizontal intensity of 20 µT and an inclination of 65°. The black light shield was placed between the observer and the test arena. N₁ and N₂ are the directions of the experimental fields; N is the direction of the local natural field.