Parsimony: When Simple Explanations Actually Work
This is the fourth post in our series on the philosophical foundations of behavior analysis. We’ve talked about Selectionism, Determinism, and Empiricism. Now, let’s dive into Parsimony—the idea that when you’re figuring out behavior, the simplest explanation that fits the facts is usually the best place to start.
But “simple” doesn’t mean lazy or shallow.
Roommate Drama: Parsimony vs. Plot Twists
Imagine this: your roommate leaves a mountain of dirty dishes in the sink again. You’re frustrated. Now, you can go two ways with this.
Non-parsimonious explanation:
“Becky thinks I’ve been hitting on her boyfriend. This is her passive-aggressive revenge.”
Whoa. That’s quite the conspiracy theory. It might make a juicy reality show, but it’s probably not the best working hypothesis.
Parsimonious explanation:
“Becky’s in a rush every morning and forgets to load the dishwasher.”
Or maybe “She’s not sure if the dishes are clean or dirty.”
Or even “She’s learned that if she leaves them long enough, someone else (spoiler: me) will clean up.”
These explanations are grounded in what you can observe and test. No guesswork about secret plots—just what’s actually going on.
Everyday Parsimony in Action
Parsimony means we look for straightforward, observable reasons for behavior before jumping to wild theories.
Say a student starts calling out in class. A reductionist explanation might say, “They just want attention” or “They’re trying to be disruptive.”
But a parsimonious approach asks:
- Does the student call out only during certain activities?
- Are they avoiding a task that feels too hard?
- Could they be seeking help in a way they know will get it?
Starting with what you can observe and test means you’re more likely to find a solution that actually works.
Parsimony Doesn’t Mean Simple-Minded
Parsimony isn’t about ignoring complexity or oversimplifying. It means honoring the facts we can see and using those to build our understanding.
If the simple explanation doesn’t pan out, that’s a cue to dig deeper—not a sign to give up or label the behavior as “just how they are.”
Why Parsimony Matters
This approach saves time, energy, and relationships. It helps us avoid spinning stories that don’t help anyone.
When you focus on observable, testable explanations, you build trust with the people you work with—whether it’s a student, a family, or your roommate.
Quick Takeaway
Next time you catch yourself thinking, “That person is just being difficult,” hit pause. Ask yourself:
“What’s a straightforward, observable reason this could be happening?”
Chances are, that’s the place to start.
The Learning Behavior Analysis Team