Laws of Behaviour

Mental models for product design

044Effect

The Decoy Effect

An 'objectively-unsuitable' option will change the value proposition for the others.

Why it matters

Although we like to imagine that we make decisions in a totally rational vacuum of 'value for money', we don't.

We broadly make decisions based on comparative values , based on the choices available.

Some companies will knowingly create an ' objectively-unsuitable ' package (or tier), with the sole purpose of making the other options feel like better value for money.

It's called a decoy, because very few people are expected to actually buy it.

Take an abstract popcorn example:

Popcorn is expensive, and you may find yourself opting for the 'Small' bucket. $8 feels like a lot to spend on popcorn.

But the presence of the 'Medium' tier, makes the 'Large' feels like better value for money .

The 'popcorn per dollar' value of the small option hasn't changed, but customers may be more likely to spend more money at the cinema.

Purchases:

• Upselling (i.e., can be used to increase average basket size). • Easier to make a decision (i.e., one option may immediately feel like the best value).

Perception of value:

• Modified value proposition (i.e., the other options feel like better value).

What to inspect

  • Check whether the experience reflects this: Upselling (i.e., can be used to increase average basket size).
  • Check whether the experience reflects this: Easier to make a decision (i.e., one option may immediately feel like the best value).
  • Check whether the experience reflects this: Modified value proposition (i.e., the other options feel like better value).

Common anti-patterns

  • Assuming users consciously notice every place where "An 'objectively-unsuitable' option will change the value proposition for the others" could apply.
  • Dense copy and parallel actions that increase mental effort unrelated to the user’s goal.
  • Ignoring downstream effects on perception of value when shipping this pattern.

Critique prompts

  • Upselling (i.e., can be used to increase average basket size).
  • Easier to make a decision (i.e., one option may immediately feel like the best value).
  • Modified value proposition (i.e., the other options feel like better value).
  • Where on this screen would "The Decoy Effect" show up as friction or misunderstanding?
  • What would a first-time user misunderstand here in under five seconds?

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