What does it mean that cue specificity matters?

Vague cues produce inconsistent activation — make cues as specific as possible.

Example: Two people decide to journal daily. Person A says "I will journal in the morning." Person B says "After I pour my first cup of coffee and sit down at the kitchen table, I will open my notebook and write three sentences about yesterday." Six weeks later, Person A has journaled nine times — mostly on weekends when the morning felt unrushed. Person B has journaled on forty of forty-two days, because the cue never required her to decide when "the morning" had arrived or where she should sit or what she should write about — every parameter was already resolved.

Try this: Take one habit you are currently trying to build and write down your cue exactly as it exists in your mind right now. Then score it against four specificity dimensions: Does it name an exact preceding action (not just a time of day)? Does it name an exact location? Does it include a sensory detail you can perceive? Does it leave zero decisions to be made in the moment? For any dimension that scores "no," rewrite the cue until all four score "yes." The final cue should read as a concrete "After I [specific action] in [specific place], I will..." statement.