(part 5 of 6)
Third after vision and hearing.
Obviously more important for the blind, e.g. paging systems that vibrate to attract attention.
The fingertips are very sensitive to changes in pressure but as with any physical contact this pressure sensation diminishes with constant application - as long as the pressure sensation is below the main pain threshold.
Tactile feedback can convey important (sub)conscious information. e.g. it is very confusing if there is no obvious tactile or audible sensation that the switch has been operated. People also complain that they don't like the 'feel' of keyboards. These complaints can be associated with the position and shape of the keys but are also directed at keyboards that require too much or too little pressure to operate the keys or have a 'soggy' feel to the key action.
If there is no obvious visual or auditory indication of the switch being operated, then touch is the next most likely means of providing that feedback.
Not particularly useful in systems design (!). These senses are not very accurate, but can be trained.
active, exploratory process with obtained rather than imposed stimulation.
Whole body, skin, extremities, esp. hands obtain information about shape, surface, weight, rigidity, and temperature. Usually the hand is seen as the organ of haptic perception. This is becoming important as an adjunct to visual virtually reality.
This is often associated with Gibson who states that the form of an object is always what is perceived and not the form of skin indentation. This is analogous to the perception of the figure and not the ground. Subjects can readily identify objects by touch even when they haven't seen them (e.g. controls).
Katz: people can learn to tell different qualities of paper apart from touch alone.
Wool graders: pull fibre strands through their hands and look at the strands: tactile and visual information highly correlated. Joints, muscles tendons also give information: e.g. throwing something, picking something up.
Physician relies on haptic information when looking for a diagnosis.
Feet and mouth also important.