What makes for a compelling interaction?

When we talk about “interaction” and “interaction design”, there is a presumption or a hope that the interactions will be valuable, interesting, engaging—maybe even stronger than all that: that the interaction will be compelling. What can make an interaction compelling? It may be helpful to look back at historically important interaction designs, so we’re not blinded by the amazing technology we have today.

Gordon Pask built interactive machines that were based on a deep understanding of human cognitive processes. Wait, let me correct that: from the 1950s to the 1970s, Pask built immersive environments and built theories of cognition together, using one to understand and reinforce the other. (In that thinking/making loop he developed a comprehensive theory of interaction and conversation, but that’s another story.)

Here’s the opening section of his article, “A Comment, A Case History, and a Plan”. (Please interpret “man” and “him” as an old-school placeholder for “human or person or he or she”.) Pask writes that in order to engage a human…

a [The interaction] must offer sufficient variety to provide the potentially controllable novelty required by a man (however, it must not swamp him with variety—if it did, the environment would merely be unintelligible).

b It must contain forms that a man can interpret or learn to interpret at various levels of abstraction.

c It must provide cues or tacitly stated instructions to guide the learning and abstractive process.

d It may, in addition, respond to a man, engage him in conversation and adapt its characteristics to the prevailing mode of discourse.

That sounds abstract but it’s completely interpretable—in other words, I can write code from it (and have). Put another way, the interaction must be new enough “to pull the user in”, to create curiosity— but not so new as to be incomprehensible or scary. And it must evolve over time. Think of a videogame that starts easy and gets progressively harder—same idea.

The opening section of the article contains a comprehensive description of what it takes to create a compelling interaction and I recommend you read it… but let’s move on to an example. Later in the same paper he describes his “Musicolour” immersive environment—a system that created a compelling interaction. Musicolour engendered a number of innovations:

Click for diagram of Musicolour

First, there was the creation of a loop where the performer made music that was sensed by the apparatus and which resulted in a light show. The performer could then respond to Musicolour’s response to the music, closing the loop. Second, interposed in that loop was Pask’s invention for amplifying variation in the performance. It amplified the performer’s variations; for example, in rhythm, it might add an additional (visual) lag to a performer’s slightly-late (aural) beat. Thus the performer was made more aware of each variation, and could decide whether to move to a stricter beat, keep it the same or, indeed, create an even bigger variation by choice.

Third, Musicolour encouraged innovation by simply becoming “bored” with repetition. For example if the performer persisted in playing at some length in the same frequency range, the lights would no longer respond to that range (while continuing to respond in others, of course — here was no simple, one-dimensional antagonist). When the lights no longer responded, the performer could only try something else to “get a rise out of” the system.

The result (at least when the performer cooperated) was a continuous flow of improvisation; a “conversation” where the performer and apparatus flowed into the other with action and response. This is “inter-action” in an important improvement to the usual meaning of Q-and-A or menu-and-mouse poking of even today’s, most modern software interface designs (which do not involve “interacting” very much at all, they are more like command-line instructions dressed up in drag). At another level it is dialogue without a set script; an unfolding of events delimited by the range of the performer.

Musicolour was developed in the mid-1950s. [This description is quoted from a more general paper about Pask.]

So, when you hear “interaction”, you might ask—is it the kind that engages because it is personalized, novel every step, and evolving? Is it the compelling kind? What would make it so?