Posted by Ben Simo
[Improvisational comedy] involves people making very sophisticated decisions on the spur of the moment, without benefit of any kind of script or plot. That's what makes it so compelling -- and to be frank -- terrifying. ... What is terrifying about improv is the fact that it appears utterly random and chaotic. It seems as though you have to get up onstage and make everything up, right there on the spot. But the truth is that improv isn't random or chaotic at all. ... Improv is an art form governed by a set of rules... How good people's decisions are under the fast-moving, high-stress conditions of rapid cognition is a function of training, rules, and rehearsal.- Malcolm Gladwell, Blink: The Power of Thinking Without Thinking
Now, reread the quote above and replace improv with exploratory testing. See a connection? Just as improvisational theater may appear to be random and chaotic (although entertaining) to the ignorant, exploratory testing can appear to be random and chaotic to those that have been taught to rely on scripts. Good improv and exploratory testing is neither. There are rules -- heuristics.
Heuristics are rules of thumb that help solve problems. In improvisational comedy, there are rules. These are not hard rules that guarantee comedy. These are rules that skilled improv actors can use to help keep things funny. Sometimes these rules don't work and actors have to adapt. And, because they aren't following a script, they can adapt when things don't work out. Some parts of improv are scripted. I am a fan of the television show Whose Line is it Anyway. Each comedy sketch in this show is given a structure (think charter) to direct the improvisation. This structure defines and restricts (think script) specific components of each sketch while leaving the bulk of the activity open to each actor to adapt to what happens as the sketch plays itself out. While we do not see it on screen, I suspect that a great deal of training, rules, and rehearsal went into the production of Whose Line. The shows did suffer from an occasional guest participant (usually a trained script actor) that was not as skilled at improv as the regulars. However, other guests (sometimes not actors) who understand the rules of improv have helped produce some of the funniest sketches.
Good exploratory testing works in the same way. Skilled exploratory testers set out with a charter -- a goal for each testing session. Skilled exploratory testers use heuristics to help them learn about the systems they test. Skilled exploratory testers practice.
Improvisation can have scripted aspects and rules that guide it. It is not chaotic and random. It is smart people using simple rules to make quick decisions and adapt to a changing environment under pressure.