**2.1 Analysis of direct contact interaction: From perception to design of devices**

Haptic interaction with objects can happen in two different ways. The first happens when a subject holds a special tool used for interacting with the surrounding environment. A pen, a joystick or a fork are examples of possible tools. The artificial creation of interaction with environment is then completely focused on replicating the information that is exchanged through the held object.

Alternatively the subject can directly interact with her/his bare fingers with the environment. In this case the artificial recreation of interaction is much more complex and is focused on reproducing the physical phenomena that occurs at the fingertip level.

We will refer to these two different cases respectively as Mediated Contact interaction and Direct Contact interaction. Hayward in (Hayward, 2008) provided a very clear theoretical description of the difference between these two modes.
