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Created page with 'File:lighterstill.jpgright|frame ==Etymology== [http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middl...'
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==Etymology==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] thresshold, from [http://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] threscwald; akin to Old Norse threskjǫldr threshold, Old English threscan to thresh
*Date: before [http://www.wikipedia.org/wiki/12th_Century 12th century]
==Definitions==
*1 : the plank, stone, or piece of timber that lies under a door : sill
*2 a : gate, door
:b (1) : end, [[boundary]]; specifically : the end of a runway (2) : the place or point of entering or beginning : outset <on the threshold of a [[new age]]>
*3 a : the point at which a physiological or [[psychological]] [[effect]] begins to be produced <has a high threshold for [[pain]]>
:b : a level, point, or [[value]] above which something is true or will take place and below which it is not or will not
==Description==
Sensory '''threshold''' is a [[theoretical]] [[concept]] used in [http://en.wikipedia.org/wiki/Psychophysics psychophysics]. A [[stimulus]] that is less [[intense]] than the ''sensory threshold'' will not elicit any [[sensation]]. [[Methods]] have been [[developed]] to [[measure]] thresholds in any of the [[senses]].
Several [[different]] sensory thresholds have been defined;
* [http://en.wikipedia.org/wiki/Absolute_threshold ''Absolute threshold'']: the lowest level at which a stimulus can be detected.
* ''Recognition threshold'': the level at which a stimulus can not only be detected but also recognised.
* [http://en.wikipedia.org/wiki/Just_noticeable_difference ''Differential threshold'']: the level at which an increase in a detected stimulus can be [[perceived]].
* ''Terminal threshold'': the level beyond which a stimulus is no longer detected.
==Aviation use==
When related to [[motion]] in any of the possible six degrees of freedom (6-DoF), the [[fact]] that sensory thresholds exist is why it is [[essential]] that aircraft have blind-flying instruments. Sustained flight in cloud is not possible by `seat-of-the-pants' cues alone since [[errors]] build up due to aircraft movements below the pilot's sensory threshold, [[ultimately]] leading to loss of [[control]].
* In flight simulators with [[motion]] platforms, the motion sensory thresholds are utilised in the [[technique]] known as `acceleration-onset cueing'. This is where a motion platform, having made the initial [[acceleration]] that is sensed by the simulator crew, the platform is re-set to approximately its neutral position by being moved at a rate below the sensory threshold and is then ready to [[respond]] to the next acceleration demanded by the simulator computer.
[[Category: Psychology]]
==Etymology==
[http://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English] thresshold, from [http://nordan.daynal.org/wiki/index.php?title=English#ca._600-1100.09THE_OLD_ENGLISH.2C_OR_ANGLO-SAXON_PERIOD Old English] threscwald; akin to Old Norse threskjǫldr threshold, Old English threscan to thresh
*Date: before [http://www.wikipedia.org/wiki/12th_Century 12th century]
==Definitions==
*1 : the plank, stone, or piece of timber that lies under a door : sill
*2 a : gate, door
:b (1) : end, [[boundary]]; specifically : the end of a runway (2) : the place or point of entering or beginning : outset <on the threshold of a [[new age]]>
*3 a : the point at which a physiological or [[psychological]] [[effect]] begins to be produced <has a high threshold for [[pain]]>
:b : a level, point, or [[value]] above which something is true or will take place and below which it is not or will not
==Description==
Sensory '''threshold''' is a [[theoretical]] [[concept]] used in [http://en.wikipedia.org/wiki/Psychophysics psychophysics]. A [[stimulus]] that is less [[intense]] than the ''sensory threshold'' will not elicit any [[sensation]]. [[Methods]] have been [[developed]] to [[measure]] thresholds in any of the [[senses]].
Several [[different]] sensory thresholds have been defined;
* [http://en.wikipedia.org/wiki/Absolute_threshold ''Absolute threshold'']: the lowest level at which a stimulus can be detected.
* ''Recognition threshold'': the level at which a stimulus can not only be detected but also recognised.
* [http://en.wikipedia.org/wiki/Just_noticeable_difference ''Differential threshold'']: the level at which an increase in a detected stimulus can be [[perceived]].
* ''Terminal threshold'': the level beyond which a stimulus is no longer detected.
==Aviation use==
When related to [[motion]] in any of the possible six degrees of freedom (6-DoF), the [[fact]] that sensory thresholds exist is why it is [[essential]] that aircraft have blind-flying instruments. Sustained flight in cloud is not possible by `seat-of-the-pants' cues alone since [[errors]] build up due to aircraft movements below the pilot's sensory threshold, [[ultimately]] leading to loss of [[control]].
* In flight simulators with [[motion]] platforms, the motion sensory thresholds are utilised in the [[technique]] known as `acceleration-onset cueing'. This is where a motion platform, having made the initial [[acceleration]] that is sensed by the simulator crew, the platform is re-set to approximately its neutral position by being moved at a rate below the sensory threshold and is then ready to [[respond]] to the next acceleration demanded by the simulator computer.
[[Category: Psychology]]