Tactile Feedback Research

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Humans perceive their world through five senses: taste, smell, hearing, touch and sight. An effective airplane attitude alert system utilizing taste or smell is obviously impractical. We have the stall horn for hearing and panel instruments for our sense of sight, and yet the stall remains the leading cause of aircraft accidents. With our instruments to view and our stall warnings to hear, stall accidents still happen every day, and to seasoned pilots who somehow lost the sensitive feel of the airplane: the feel of the wind over the wings, the slight shudder when the wing is close to stall, or the sliding feeling in uncoordinated turns. Conventional pilot training continues to stress strong dependence on the instruments: the airspeed indicator for angle of attack, the ball, tachometer, gyros and so on. These are all visual indications of the aircraft’s attitude. The problem is that pilots are not always looking at the instruments. Sometimes engine noise can drown out the stall horn. Turbulent conditions can interfere with the ability to process information.

It is time to consider the sense of touch.

“A real pilot knows how to fly by the seat of his pants.

“The phrase comes from back in the day when airplanes—being very basic without all the fancy gadgetry planes have today— were flown by pilots who reacted to the feel of the plane. Naturally, the part of the body that had the most contact with the plane was the aviator’s backside. The phrase ‘flying by the seat of your pants’ came to mean how pilots flew planes, which was to react to how the plane felt to the pilots in such situations as determining wind speed and the state of the plane. Sometimes pilots were unable to see while they were flying because of cloud or fog, and that’s when flying by the seat of their pants [or] instinctively really paid off.”


Scientific Studies demonstrate the efficacy of tactile feedback.


Touch is considered the most acute of the senses. Your entire body incorporates this sense. While the seat of your pants is not considered to be the most sensitive part of your body, your fingertips are. Fingers contain among the highest concentration of nerve endings over most other parts of the body.[1] Consider the sensitivity required to read Braille.

In 2007, the US Army Research Laboratory conducted a remarkable study in which they reported that a system that uses only one sense to gather information about the environment will likely disturb our ability to operate “naturally” within the environment.[1] That is to say that if a pilot is only relying on his visual interpretation of his instruments, he is less able to make use of his other faculties to interpret and act in his airplane. If one were to add a heightened stress situation, such as an engine problem, imminent obstacle or other cockpit emergency, the pilot is likely to misinterpret his airplane’s attitude, leading to disastrous results. More studies reported that the use of the skin as an information channel can be beneficial within a system, especially when the visual and/or auditory channels are overloaded or weakened.[2] When a sensory modality is overloaded with information and it is the sole input for information transfer, the user becomes incapable of processing future incoming information via that same mode, the incidence of errors will increase and situational awareness and overall user performance will decrease.[1] The scientific evidence supports a “redundant modality” for assuring a pilot receive the information required to operate the aircraft safely. The redundant modality has been shown to decrease the incidence of spatial disorientation for divers and astronauts.[3] This means that receiving the same information to more than one sense at once enables our ability to remain oriented!

Research confirms:

• Tactile systems have been found to be most efficient for the orientation, navigation and communication domains.[3]

• Accuracy on testing using tactile modalities found them to be more accurate than with visual display only.[3]

• Tactile and visual information, as opposed to visual information alone, improves performance.[2]

• Tactile feedback yields a quicker motor response for the task.[4]

The Army Research Laboratory study concluded that, “because humans have a limited capacity to receive, hold in working memory, and cognitively process information taken from the environment, the use of one sensory modality to convey information within a system can overload that modality.[1]

[1] Myles, K.; Binseel, M. S. The Tactile Modality: A Review of Tactile Sensitivity and Human Tactile Interfaces. ARL-TR-4115. Army Research Laboratory 2007.
[2] Raj, A. K.; Kass, S. J.; Perry, J. F. Vibrotactile displays for improving spatial awareness. Proceedings of the IEA 2000/HFES 2000 Congress, 181-184, 2000.
[3] Castle, H.; Dobbins, T. Tactile Display Technology: A Brief Overview of its Benefits Over Visual and Audio Displays. Ingenia, Technology and Innovation, 31-34.Retrieved on March 3, 2006 from http://www.raeng.org.uk/news/publications/ingenia/issue20/ Castle.pdf (2006).
[4] Akamastu, M.; MacKenzie, I. S.; Hasbrouq, T. A Comparison of Tactile, Auditory, and Visual Feedback in a Pointing Task Using a Mouse-Type Device. Ergonomics 1995, 38, 816-827.