that varying levels of abstraction are transparent to
the user and do not interfere with the understanding of the interface.
As an example of abstraction introduced in the
electronic age, consider how station selection on the
radio was done five decades ago, and how we do it
today. In the 1960s the radio had a tuning knob and
dial for selecting the receiving station. As the knob
was turned, a line would move across a graduated
background, providing the user with a direct cor-
relation between the rotation of the knob and the
movement of the line. The background indicated the
appropriate for those who have lost their sight or
have difficulty with fine motor control. For these
people, manipulating large three-dimensional
objects gives potential relief from the minuscule
buttons of a television remote controller’s two-
dimensional interface.
September + October 2010
[ 1] Norman, D. “Natural
User Interfaces Are Not
Natural.” interactions 17,
3 (2010): 6-10.
[ 2] Ullmer, B and
Ishii, H. “Emerging
Frameworks for Tangible
User Interfaces.” IBM
Systems Journal 39, 3-4
(2000): 915-931
interactions
location to which the line should be moved in order
to tune to a radio station. Current radio designs
present the user with a range of buttons, which
can be depressed. Searching for a radio station is
accomplished by depressing a specified button and
listening to the audio while a circuit changes frequency. The user has little control over the rate at
which the frequency changes, at least not the fine
control afforded by the tuning dial. This additional
abstractness has been added to numerous consumer items, supposedly in an attempt to add more
functionality into an ever-decreasing volume.
A number of researchers are investigating the
removal of abstraction layers by inventing new
direct-manipulation mechanisms, often building
on prior knowledge [ 1]. One group of research-
ers is grounding work in Tangible User Interfaces
(TUIs) [ 2]. It is my opinion that TUIs are particularly
execution on a computing device such as a desktop
computer, a custom-made low-cost computer, or
a computing device embedded in the world of the
novice programmer. I’m motivated by the innate
ability of humans to manipulate real-world objects
using their hands. This is accomplished with great-
er ease than the manipulation of virtual objects
using artificially created instruments such as the
computer keyboard.
