HCD.6.1:10 - Rationale

A term can direct attention only through some usable relation to what the learner encounters. Contrasting cases and states can develop that relation. Varying an incidental feature then asks whether recognition depends on it.

The method sits inside the design of representative practice. It can prepare a constituent contribution before the learner performs the encompassing task, but that larger task determines which distinctions are useful and which combinations must eventually be learned.