The Strange Self-Motion Illusion

Anomalous experiences tend to jolt one out of one’s comfort zone, tell us interesting things about how the mind works.  A vivid déjà vu, strange coincidence, or unexpected illusion can all be automatic attention-grabbers.  Some of the oddest experiences are visual. When a large part of the visual field moves, the viewer can momentarily believe that they have moved in the opposite direction.

The most common example occurs when looking out of a stationary train window at a station, and a nearby train moves away, you erroneously perceive that your own (stationary) train is moving in the opposite direction. This experience can happen on the railway, the road, at sea or in space, and it can cause accidents (e.g. see https://safety4sea.com/relative-motion-illusion-leads-to-collision/).

The other day, driving along a busy A3 towards London on ‘autopilot’ (Vatansever, Menon and Stamatakis, 2017), I reached a  set of traffic light. In the middle lane, my vehicle was boxed in all sides by other vehicles so that I could not myself see the traffic lights. Suddenly I felt as if my vehicle was being pulled backwards so that my car would impact the one behind, a potential disaster.  I immediately slammed my foot on the brake and felt a surge of adrenaline. Thankfully, my perceptual-motor system quickly snapped back to reality – I realized that I was stationary and that the surrounding vehicles were moving forwards.  Reset! In less than a second, my foot came off the brake and onto the accelerator.  I had experienced the ‘Self Motion Illusion’ (Riecke, 2010).

My brain had falsely concluded that my vehicle was moving backwards. This is the natural response of a perceptual system with a default setting that expects constancy (Day, 1972).  I wish to argue that perceptual constancy is based on a universal principle of ‘Psychological Homeostasis’ (Marks, 2018).  When my perceptual world went haywire at the traffic lights, a rapid correctional ‘reset’ brought me back to my senses.

The rapidity of the reset is required to prevent a potential accident. This fact may be evidence of a general reset principle which is operating to produce equilibrium at each and moment in a conscious being.  Alternatively the experience was reset by the fact that I saw the surrounding vehicles moving away around me. It is hard to say from a single uncontrolled experience.

References

Day, R. H. (1972). The basis of perceptual constancy and perceptual illusion. Investigative Ophthalmology & Visual Science, 11(6), 525-532.

Marks, D. F. (2018). A General Theory of Behaviour. London: SAGE Publications.

Riecke, B. E. (2010). Compelling self-motion through virtual environments without actual self-motion–Using self-motion illusions (‘vection’) to improve VR user experience. Virtual reality. InTech.

Vatansever, D., Menon, D. K., & Stamatakis, E. A. (2017). Default mode contributions to automated information processing. Proceedings of the National Academy of Sciences, 114(48), 12821-12826.