Grandma’s Law

Like Grandma used to say, “You can’t have your ice cream until you finish your broccoli!” Informally known as “Grandma’s Law” or the “first and then” rule, the Premack principle utilizes behaviors that happen with a high-probability or high free operant behavior (this is most often preferred) to use as a reinforcer contingent upon the completion of a low-probability or low frequency behavior (usually non-preferred).

For example, if you want your learner to brush his teeth, you may say “first brush your teeth, then you can watch TV.” We often apply this rule to ourselves! Example: When I’m finished with my errands, I can go shopping.

Identifying “high-probability” or “high frequency” behaviors can be done by simply observing the individual in his/her natural environment. What do they typically spend more time doing?

You can optimize the success with using this intervention simply by accompanying it with a visual cue. This can be pictures, icons, and/or words. Teaching him/her to remove or cross off the item when it’s completed will also begin teaching him/her to self-monitor, which will allow you to add multiple icons before he/she can gain access to the preferred item or activity more smoothly.