Thursday, September 12, 2013

Backward & Forward Chaining






Chaining is a way to teach a multi-step or complex skill. While often used as a component of ABA instruction, chaining can be used to teach anyone a complex skill. A complex skill is a skill that really consists of several small behaviors that are linked or chained together, to accomplish a terminal goal. An example of a skill consisting of several discrete behaviors is wiping a table.



Teaching a skill using chaining is commonly recommended if the child can only perform some of the steps, consistently misses/skips steps, or is completing steps incorrectly. For example, on a daily basis the child throws their wet toothbrush in the sink instead of putting it in the toothbrush holder. That would be a good situation to introduce chaining into. Another issue I see commonly is the child who independently uses the bathroom, and then consistently fails to button/zip their pants back up. That is a child who could benefit from a chaining program.



A way I like to explain chaining is by comparing it to cooking. I am a recipe person. Even if I have made something multiple times, I still like to have the recipe in front of me. Imagine I asked you to make me some oatmeal raisin cookies, but I gave you no recipe to follow and no expectations of exactly what to do. What kind of raisins do I like? Do I like cinnamon in my cookies or vanilla extract? Do I prefer chewy or crisp cookies? You would likely start or finish the cooking chain successfully, but have errors or missed steps in the middle. This is why using chaining to teach a skill can be so helpful. For a child with Autism, hearing a demand like “make your bed” may not mean anything. They may need a recipe to follow, which clearly states my expectations of how to complete the task.


The 3 types of chaining are: Backward chaining, Forward chaining, and Total Task chaining.



Backward Chaining- Backward chaining refers to teaching a behavioral chain beginning with the last step: you would completely prompt the entire chain of behaviors except the last step. Using the tooth brushing example, the child would be prompted to do every single step and then would independently put the toothbrush in the toothbrush holder. Backward chaining is recommended if the child can successfully complete more steps at the end of the behavior chain. Backward chaining also has the advantage of creating a link between the most work and the biggest reinforcer. If I am using backward chaining to teach a child to make French toast, then I would prompt every step and have the child independently use a spatula to move the toast from the pan to a plate. Then we get to eat! So the most work (independent step) led to the biggest reinforcement (consuming the food). Once the last step is mastered at an independent level, then move to the last 2 steps, then the last 3 steps, etc.



Forward chaining- Forward chaining refers to teaching a behavioral chain beginning with the first step: have the child complete the first step independently and then prompt all remaining steps. Using the tooth brushing example, the child would independently pick up their toothbrush out of the toothbrush holder, and then all remaining steps are prompted. Forward chaining is recommended if the child can successfully complete more steps at the start of the behavior chain. Forward chaining has the advantage of using behavior momentum, as the 1st step is often the simplest, easiest step. If I am using forward chaining to teach a child to make French toast, then I would have the child get the bread out of the refrigerator independently, and prompt every other step. Once the first step is mastered at an independent level, then move to the first 2 steps, then the first 3 steps, etc.



Total task chaining- As the name implies, total task chaining is when you teach the complete behavior chain one step after another. Total task is what most teachers or parents naturally use to teach a skill. E.g. "Okay turn the water on...now soap up your hands....good, now scrub your hands together", etc. The adult walks the child through each step, prompting as necessary. For a child with Autism, this may still be too complex of a teaching style. For that reason, backward or forward chaining is usually more commonly used for kiddos with Autism. 



 Lastly, to create a chaining program you will need a Task Analysis. A task analysis isn’t as complicated as it might sound. It is basically the GPS step- by- step directions to completing the skill. A task analysis is typically created by completing the skill yourself or watching someone else complete the skill. It’s very important not to just write up a task analysis based on your memory. Even simple tasks, like making a sandwich, can have small important steps that you may inadvertently skip. If you don’t teach the step, then you really can’t blame the child for not completing the step. You could also consult with a professional or do some research on how to perform a specific task. I could easily create a task analysis for tooth brushing, but if I had to teach an older client to change the oil on a car, I definitely could not easily write a task analysis for that. I would need to do some research, perhaps talk with a mechanic, etc.

 Here’s a tip: after you create a task analysis, complete the behavior chain yourself to make sure you haven’t skipped any steps or placed steps out of order. It happens more often than you might think.




*Resource:



-Here is a link to a massive amount of free Task Analyses  covering a wide range of skills.

-A solid understanding of Reinforcement and Prompting is necessary to teach using chaining.




18 comments:

  1. Should the criterion for mastery of a task analysis always be 100%?

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    1. Great question. Here is a tip: when talking about programming, if you use the word "always" then the answer is probably no.
      Mastery criteria is not always 100% for any instructional program, but for adaptive skills mastery criteria is usually pretty high.
      The reason why, is any adaptive skill I cannot perform for myself reduces my independence and/or quality of life. Like toothbrushing, bathing, using a toilet, etc. Anywhere in those skill chains where I miss a chain or two, that means someone will have to help me complete the task.

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    2. Hi,
      I want to my daughter(12) to get my work from my house by bus and c-train using forward chaining. it will take 40 minutes. she is not familiar with these area. because we moved. if I teach her, could you tell the steps? Thanks.

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    3. Hi there,

      The best way to select the steps to teach the chain is to perform the behavior yourself, or observe someone perform it. So you could start at the location where your daughter would begin, and then do each step she would need to do in order to get home. That way you can be sure not to skip/forget to teach certain steps along the way. Good luck!

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  2. I.....LOVE....your....site :D:D:D:D:D:D

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  3. Do you use reinforcement at every step of the chaining process?

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    1. Hi there,

      That will depend on the learner, and how the intervention is going. I have taught some skills where we could reinforce at the end (like putting on a jacket), and then other longer, or more aversive, skills like tooth brushing did require much more frequent contact with reinforcement. Or, modifying the task to be more interesting from the learner's perspective. For one 6 year old we used an electric and colorful tooth brush while also playing a cartoon clip on a DVD player of a child brushing their teeth. For her, this was highly reinforcing.

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  4. I have a question regarding a task analysis such as toothbrushing and error correction procedures. If a student happens to error after prompts have been faded would you restart the trial? For example if student has already shown ability to complete toothbrushing independently.

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    1. It really depends on what is breaking down in the chain, to cause the error. For many of my clients, even at independence with a chaining procedure they may still need the visual prompt (visual strip). So let's say when the visual strip is removed, they start skipping steps. Or maybe if mom/dad no longer checks in on them, they start skipping steps. That would be an indication that we faded a support too fast, and the client still needs that support. Or, let's say the materials change (new toothbrush, new bathroom) and the chaining steps start to deteriorate then that would indicate difficulty generalizing.
      So it really depends on why are errors happening, if the skill is supposed to be mastered. Beyond just restarting the trial, it may be that re-teaching is needed.

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  5. Thank you for your feed back! What about if it's more behavioral in the sense that they are engaging in the error as an attempt to escape the demand?

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    1. It sounds like you may need to conduct some functional assessment to determine what is going on. If this is a mastered skill, then why is the learner now attempting to escape performing the skill? Is the demand too high, or did it change in some way? Is the reinforcement too low? Your intervention will vary based on the function, and the factors contributing to that function.

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  6. I just found your site in googling "chaining" and it's brilliant! Question: Can chaining every inadvertently reinforce an undesirable behavior? To clarify, as parents, is it possible that we teach our children to become prompt dependent and what is your advice for breaking this cycle?

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    1. Glad you found the blog!

      I know exactly what you mean, but I would refer to what you are describing more as "Shaping" vs "Chaining". Here is a basic explanation of the difference: chaining is a tool to teach a behavior chain, or a long series of behaviors needed to perform a terminal behavior. Shaping is the practice of reinforcing closer and closer steps towards a specific behavior. I don't come across many people who unintentionally chain, but unintentional shaping is something I see on a regular basis!
      For example: in a classroom, a child has learned to kick her shoes across the room to be sent to Time Out in the hallway. How did that happen? Well, the behavior probably started small maybe with refusing to do work, then making sounds, then standing up, and then removing shoes. As the behavior progressed, the wrong thing was reinforced. Over time, this leads to the child learning if they want to leave the classroom the best way to make that happen is to be disruptive.

      My recommendation for avoiding shaping up problem behaviors in this manner is to learn more about behavior/ABA. The more parents understand behavior and how behaviors get stronger or weaker, the better position they will be in to avoid "accidentally" shaping up problem behavior.

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  7. Your Blog is awesome!!

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