The Background - Artificial Human Sensors: Science and Applications - page 4

of man, instead, focuses on observing nature from the outside. The continuous
feeling is that the existing requirements are not in balance with our environment.
One reason for that can be that our sensing abilities are not adopted for the present,
i.e. in the modern living pattern of today. The examples given below intend to
show these differences and everyone may also calculate the effects that these lim-
itations in perceptual performance may provide in the long term. However, by
getting aware about perceptual limitations, we also are able to respond and ei-
ther change our behaviours or adapt to the type of social life that is acceptable to
provide the best possible condition for development.
1.2.1 The Skin Sense
The largest perceptual sensing organ is considered to be the skin of the body. The
skin is the cover around the human that protects our internal organs from external
damage. The perceptual organ, skin, is the interface through which we are able to
touch the world and physically sense the environment.
Also in most cultures the skin exhibits a social identity by indicating the age,
cultural affiliation, and also health status, social class or geographical connection
of an individual. However, the skin is mainly the sensing organ, comprising of ap-
proximately two m 2 with an average weight of four kg (which naturally depends
on the size of the person) and is constantly renewed throughout a person's lifetime.
Everyone may recognise their own perception of the skin when exposed to
sun, heat, cold, pressure, etc. Indeed the skin is a major sensing organ that provides
important information about the environment contact to the body. The human skin
is, with some exceptions, in principle is hairless and this is connected to the body's
ability to control the body temperature by the mechanism of sweating effectively
and evaporation of sweat.
The influence of hair on the skin may affect the perceptual sensing capability
of externally sensing the environment, i.e., the skin is able to sense the environ-
ment even if no contact with the skin occurs. However, most of the skin is directly
connected to the perceptual sense of touch and has during evolution considered of
being a central function primates explor the world.
The perceptual power of touch involves sensation through pressure, vibration
or temperature in order to estimate the qualities, for example tactile texture. The
tactile qualities will result in wide perceptual impressions ranging from sensual
pleasure to extreme pain.
The skin comprises of a complex network of nerves, which form the connection
between actual touch and the result experienced from that sensation. The nerve
system is a connection of different receptor functions recognising the influence
of contact properties. The tactile textures might be referred to (in contrast to the
visual textures) immediate tangible skin contact, i.e., the feeling of an object sur-
face. The tactile function has through generation back primarily been used for two
main functions, to explore food and to communicate between humans. The inter-
play between senses is crucial to determine the quality of food or similarly when