Your kindergarten teacher asked you how many senses there are and you and your classmates listed "seeing, hearing, touch, taste, and smell". Your kindergarten confirmed that we have five senses and you all drew a picture...
Your kindergarten teacher was wrong!
But so was Aristotle. Indeed our common understanding of having five senses dates to ancient times when the senses were not fully understood.
The vestibular system located in your inner ear is a fundamental sensory system that detects motion of the head and tilt of the head relative to gravity (like the accelerometers and gyroscopes in your cellphone). It is a system that quickly detects self-motion and quickly triggers reflexive eye and postural movements to maintain perceptual and postural stability.
Surprisingly, our research has shown that the perceived timing of vestibular stimulation is slow. When asked to detect vestibular stimulation, reaction times are markedly slower than for light, touch and sound. When asked "which came first, your head moving or a sound?", typically your head has to move well before another stimulus for the two stimuli to be perceived as occurring at the same time.
These results are surprising considering the speed with which the vestibular system detects and responds to self-motion and we are currently delving deeper into basic research to determine the neural mechanisms underlying this slow vestibular perception as well as developing practical applications in calibrating virtual reality environments and vestibular prostheses.
Learn more about this surprising discovery:
- Barnett-Cowan M (2013) Vestibular perception is slow: A review. Multisensory Research 26: 387-403
- Soyka F, Bülthoff HH, Barnett-Cowan M (2013) Temporal processing of self-motion: Modeling reaction times for rotations and translations (PDF). Experimental Brain Research 228: 51-62
- Barnett-Cowan M, Raeder SM & Bülthoff HH (2012) Persistent perceptual delay for head movement onset relative to auditory stimuli of different durations and rise times (PDF). Experimental Brain Research 220: 41-50
- Barnett-Cowan M & Harris LR (2011) Temporal processing of active and passive head movement. Experimental Brain Research 214: 27-35
- Barnett-Cowan M & Harris LR (2009) Perceived timing of vestibular stimulation relative to touch, light and sound. Experimental Brain Research 198: 221-231