What is Physical Interaction?

Published September 13, 2017

What is physical interaction?

In Chris Crawford’s “The Art of Interaction Design,” we are presented with a concise definition for interaction: “_a cyclic process in which two actors alternately listen, think, and speak.”  _This definition is general to all types of interaction and does not mention the means by which this interaction happens.  ”Listen, think, and speak,” in this case can refer to any sort of interaction, not just verbal.  In our course on Physical Computing, however, we are particularly interested in physical interaction between humans and some sort of machine or computer.

Imagine two or more disembodied thinking entities floating in the ether, unable to speak or otherwise translate their private thoughts, emotions and wants to one another.  Without any means to interact physically (or telepathically), they cannot begin to conceive of one another.  It is only when you place these thinking entities within a physical body – either human, animal or machine – that they can translate their inner reality into a mutually intelligible physical form.  As these entities can now communicate externally (through speech, gesture, touch, musk, etc.), they can also make an effort to understand and respond to the communications of others.  Physical interaction is the means by which we both share our inner reality externally and respond to this sharing from others.  The limits of this interaction are the limits of our mutual inputs and outputs: a computer without a microphone cannot possibly respond to verbal commands any more than humans can respond to infrared signals.

What makes for good physical interaction?

In class, we were challenged to reject the idea of an intuitive interface – an idea that minimizes our unique experiences and unfairly assumes a shared experience or behavior – and instead focus on actually understanding those for whom we will design our various projects.  Indeed, that intuitive interaction is a fallacy should be obvious to anyone who has tried to explain how to use a specific piece of software to someone unversed in computers.  That said, those qualities that makes a certain interactive design or interface feel intuitive to its user are desirable.  What are these qualities?

– The results of our actions should be immediately apparent through some physical feedback.  Through consistent feedback on our actions, the underlying logic of the interaction becomes much easier to learn.

– The type of physical interaction should match the intended effect: moving a computer mouse is a good example of this: both the physical object and the digital avatar slide.

Examples of non-interactive digital technology?

– While a radio receiver may be somewhat interactive (in that we can adjust a knob and have the volume change accordingly), radio as a system is not interactive in that it is a one-way stream of data.

– GPS is a similar example of a non-interactive one-way stream of data accessible to its user through an interactive interface.


What else makes certain interfaces feel intuitive?  Do they simply map a new set of commands onto an existing behavior?  Why is it that an arrow pointing up indicates almost universally that we are meant to go forward (and not upwards)?