What is Physical Interaction?

What is physical interaction? What does it have to consist of to be considered ‘interactive’? Have we misinterpreted what interaction design is at it’s fundamental core?

In Crawford’s The Art of Interactive Design he states the definition as a conversation with two actors who “listen. think, and speak.”

In A Brief Rant on the Future of Interaction Design, Bret Victor uses this video to define physical interaction, not through tasks to complete (human need) or technology, but by our own natural capabilities as humans, such as using our senses of touch, balance, strength, etc. to navigate the world around us.

Using these sources, I would define physical interaction as natural actions that occur with two or more “actors” (as defined by Crawford), where there are clear and immediate feedback loops (responses) to various inputs (either analog or digital).We must be sure to contrast the difference in thought between the two authors. Crawford states that an interaction is the act of listening, thinking and speaking. Victor argues further, stating that physical interaction must emulate natural expressions with our body using all of our senses.

I believe physical interaction does not need to emulate these natural “expressions”, but some of the best examples of great physical interactive experiences have the human element ingrained in their design. Let’s take cars for example:

As we had been pretty nomadic people for a large part of our history, humans have moved around to various geographic locations, using either our own legs as locomotion or riding atop horses or in carriages. This was a fairly passive way to travel (unless the need called to gallop to a certain destination). Very little input needed to be given to the animal to guide them into a certain direction. With the advent of cars at the turn of the 20th century, we has a whole new set of “tools” to interact with to navigate the roadways (which resulted in an astonishing amount of crashes..surprise surprise). We shifted as a human race from passive riders to active drivers.


As technology progresses, and the dawn of the autonomous vehicle is upon us, we will slowly transition back to what was most natural for us, returning as passive riders once again, stepping in only when intervention is needed.


What makes for good physical interaction?

I believe a good physical interaction incorporates three things:

  1. Affordance in the product’s design
  2. Using your senses to interact with an object, either physically or digitally
  3. Feedback from the product to the user

According to Don Norman, author of The Design of Everyday Things, an affordance is the design aspect of an object which suggests how the object should be used. Essentially it’s a visual clue to its function and use. This is important for the user to understand how they should interact. Next, for a good physical interaction, the user must use their senses to interact with the object first. The most common initial action is usually tactile (grabbing, pressing, swiping, tapping, etc…). The product will be thinking (processing) a response, which will then give the user some information that their action is either complete or incomplete, thus completing the feedback loop. When these three things can work together, and learn from each other as they are used, this is what creates good physical interaction.

There are several examples of digital technology that are not interactive. If we follow Crawford’s definition to interaction, TVs, Podcasts, online blogs and media are fairly non-interactive. You can make the argument that online media sites are interactive in the comments section, but not to the extent that it can completely change a written/video/audio piece on content that is already published. TVs are not interactive as you can’t engage with a TV, you can only control it. Podcasts, although new, are not interactive unless they are recorded live with full audience participation.