The complicating factor is that mental rehearsal is both dramatically weaker at producing a habit than actual activity and also mindbogglingly easier to do. If

The complicating factor is that mental rehearsal is both dramatically weaker at producing a habit than actual activity and also mindbogglingly easier to do. If you want to get into the habit of drinking a glass of water each morning you can think about this many times during the day, and rehearse it as you drift off to sleep at night, ready to wake fully committed. What happens when you multiply the two efficiency factors together forming the product of the near-zero effectiveness with the huge frequency of repetition? More than one? Less than one? I think it is sometimes more than one, which means that research that look at habit as activity only, and discards thought, is confusingly incomplete.