An everyday example of vection is sitting in a stationary train at a platform and seeing another alongside start to move; this may give the impression that you’re moving in the opposite direction: a visual stimulus has fooled you. Vection can have unfortunate side-effects, because a conflict between what your eyes are seeing and what the motion sensors in your ears are telling your brain is a classic cause of motion sickness.
Designers of video games want to enhance players’ feeling of being part of the action by making it seem that they are moving within the scene. But the small size of most displays and the risk of motion sickness have constrained them. A combination of new types of wrap-around visual displays and motion sensors such as treadmills is now changing that because they can couple the movements of players with what they are seeing. As a result, vection has become common as a term of art within the field.
Vection derives from the Latin verb vehĕre, to carry or convey, which also appears in compound verbs such as convection as well as in vector, the mathematical term for a quantity with direction as well as size. An old sense of vection, which comes directly from Latin, is the action of carrying, in particular the transference of a disease from one person to another (vector has also taken on the sense of an organism responsible for such transfers).