sensation Sensation (psychology) refers to the processing of the senses by the sensory system. Sensation or sensations may also refer to: In arts and entertainment In literature *Sensation (fiction), a fiction writing mode *Sensation novel, a British ...

of falling occurs when the

labyrinth In Greek mythology, the Labyrinth (, ) was an elaborate, confusing structure designed and built by the legendary artificer Daedalus for King Minos of Crete at Knossos. Its function was to hold the Minotaur, the monster eventually killed by the ...

or ''vestibular apparatus'', a system of fluid-filled passages in the

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

, detects changes in acceleration. This sensation can occur when a person begins to fall, which in terms of

mechanics Mechanics (from Ancient Greek: μηχανική, ''mēkhanikḗ'', "of machines") is the area of mathematics and physics concerned with the relationships between force, matter, and motion among physical objects. Forces applied to objects r ...

amounts to a sudden acceleration increase from zero to roughly 9.81 m/s². If the body is in

free fall In Newtonian physics, free fall is any motion of a body where gravity is the only force acting upon it. In the context of general relativity, where gravitation is reduced to a space-time curvature, a body in free fall has no force acting on i ...

(for example, during

skydiving Parachuting, including also skydiving, is a method of transiting from a high point in the atmosphere to the surface of Earth with the aid of gravity, involving the control of speed during the descent using a parachute or parachutes. For ...

) with no other momenta (rotation, etc.) there is no falling sensation. This almost never occurs in real-life falling situations because when the faller leaves their support there are usually very significant quantities of residual momenta such as rotation and these momenta continue as the person falls, causing a sensation of dysphoria. The faller doesn't fall straight down but spins, flips, etc. due to these residual momenta and also due to the asymmetric forces of air resistance on their asymmetric body. While velocity continues to increase, the downward acceleration due to

gravity In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stro ...

remains constant. Increasing drag force may even cause a feeling of ascent. The vestibular apparatus also detects spatial orientation with respect to visual input. A similar sensation of falling can be induced when the eyes detect rapid apparent motion with respect to the environment. This system enables people to keep their balance by signalling when a physical correction is necessary. Some medical conditions, known as

balance disorder A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking. It may be accompanied by feelings of giddiness, or wooziness, or having a sensation of movement, spinning, or floating. Balance ...

s, also induce the sensation of falling. In the early stages of sleep, a falling sensation may be perceived in connection with a

hypnic jerk A hypnic jerk, hypnagogic jerk, sleep start, sleep twitch, myoclonic jerk, or night start is a brief and sudden involuntary contraction of the muscles of the body which occurs when a person is beginning to fall asleep, often causing the person t ...

, sometimes awaking the sleeper abruptly.

Labyrinth

The

vestibular system The vestibular system, in vertebrates, is a sensory system that creates the sense of balance and spatial orientation for the purpose of coordinating movement with balance. Together with the cochlea, a part of the auditory system, it constitutes ...

works with other sensorimotor systems in the body, such as the visual system (eyes) and skeletal system (bones and joints), to check and maintain the position of our body at rest or in motion. The vestibular apparatus functions by detecting forces that act upon bodies including gravity. There are two sections in the labyrinth that are helpful for accomplishing those tasks: the semicircular canals and the otolithic organs.

Balance disorder

is a condition that makes a person feel nausea, disorientation or dizziness as if moving, spinning or falling even though steady. Balance disorder can be caused by medication, problems of the inner ear or the brain.

Hypnic jerk

Hypnic jerk, also called hypnagogic jerk, is a normal reaction that can be caused by anxiety, caffeine, a dream, or discomfort of sleeping. A hypnic jerk is the feeling triggered by a sudden muscle twitch, causing the feeling of falling while sleeping or dreaming. Hypnic jerks typically occur moments before the first stage of sleep. About 70% of people have experienced hypnic jerk. Hypnic jerks are most common in children, when dreams are considered the most simple.

References

{{Reflist Perception Falling

Labyrinth

Balance disorder

Hypnic jerk

See also

References