Defining Physical Interaction

As the brains and sensors in the objects around us become more sophisticated, there are great opportunities to design the interaction that mediates our relationship with them. After reading the initial chapters of Chris Crawford’s The Art of Interactive Design, I agree that the most meaningful interactions require a full feedback-loop between the object and the human that includes Listening, Thinking and Speaking from both parties (if not always literally).

An excellent display of this is relationship between a car and the driver. The car is constantly “Listening” to your body movements, “Thinking” by converting those your movements into turning, accelerating, etc. and “Speaking” through meters, sounds and force feedback. This “loop” is so tight, that both actors are constantly doing all three things.

The strength of this interaction is that the fidelity of the loop is high and constant. It’s not limited by resolution or a frame-rate or an inability to interpret the data. Those aren’t always assumptions that can be made with human-computer interaction, especially when it comes to technologies like camera vision (I’m looking at you Kinect). The more “understanding” that each actor has over the intent, abilities and expectations of the other actor, the greater the quality of interaction becomes.

Interaction comes in degrees and a high-quality loop isn’t always necessary. In its simplest form, an interaction can happen between a human and a light-switch—albeit not a very interesting one. The light switch “Listens” by virtue of it being a switch, “Thinks” by interpreting it’s position into the appropriate state, and “Speaks” through the light bulb. Playing any 3D game on a laptop is not much more than this same interaction happening millions or billions of times per second.

Remove this reactionary relationship, and the interaction ceases to exist. There are examples of digital technology all around us that wouldn’t be considered interactive. My favorite might be the GPS system. We can sample from it like listening to music from a cello, but our actions have no impact on the behavior of the satellites. Far from making it a “bad” technology, this lack of interaction is one of the beauties of it’s design. Similarly, automated machinery, clocks, and CCTV are sophisticated digital technologies, but they are not interactive.