Chains are made up of individual behaviors held to together by cues.

Each cue reinforces the behavior that came before it and signals the opportunity for reinforcement of the behavior that comes after it. This is how cues are the glue that hold a chain together.

When building a forward chain we start with the the first behavior and it’s associated cue, then we add another cue + behavior and then another and so on:

In back chaining, we start with the last cue + behavior, then the one before that, then the one before that and so on:

The end result looks identical regardless of how it’s taught, but the teaching of it is completely different.