Shaping- Big Behavior Change Through Little Approximations

Written by Victoria Smith, B.S., BCaBA

Shaping is a behavioristic term defined as:  reinforcing successive approximations towards a terminal behavior.  I chose this topic because I often find myself referring to “shaping up behavior” and I said it recently in conversation with my mother.  She stopped me and asked “What is shaping?  Does that involve physical force?”  The answer is no.  Shaping is actually a nice and easy way to sustain behavior change.  It uses previously demonstrated behaviors to make little steps to better or more appropriate behavior.  If done correctly, it will be easy for the child to contact reinforcement.

The first step to shaping is to define the terminal behavior that you would like to see.  For example, whether it is a vocal response such as “cookie” or whether it is a self-help skill such as brushing teeth for 30 seconds, define what you would ultimately like to have the child do.  The terminal goal should be an appropriate and acceptable behavior in which there has been a pre-requisite skill already observed.  To shape the word “cookie,” the child should already be able to say the “cah” sound.  To shape tooth brushing, the child should be able to hold a tooth brush.

The next step in shaping is to define the intermediate steps towards the terminal goal.  These steps should be small and easy to accomplish.  For example, the next approximation to “cookie” from “cah” may be “co” and the next approximation from holding the toothbrush may be lifting the toothbrush to head level.  One should map out all the approximate steps towards the terminal goal.  In addition, find a high magnitude reinforcer that is easy to deliver.

Now that the steps and reinforcement are defined, you can start the shaping process. Start by reinforcing the beginning step, the “cah” or the holding the toothbrush, until the child is engaging in the behavior consistently.  Then withhold reinforcement for that step; this is putting the approximation on extinction.  When reinforcement is withheld for a behavior that has been previously reinforced, an extinction burst will occur.  (See extinction blog for more information.)  The extinction burst will produce novel behaviors that are close in topography to the previously reinforced behavior.  The point of the extinction burst is that likely the child will demonstrate the next approximation of the terminal behavior that you can reinforce.  Reinforce the next approximation immediately after seeing the behavior and continue to reinforce observations of this approximation until the behavior occurs consistently.  You move through all the approximations in this manner: reinforcing and then putting the behavior on extinction once the current approximation is demonstrated consistently.  During the extinction burst, wait for the next approximation and reinforce immediately after seeing it.  Once all approximations are met and the terminal behavior is observed, make sure to reinforce the terminal behavior after the shaping process is complete.

As you can see, shaping is a process that is based solely on reinforcement strategies and is an easy way to get a child to gain new skills.  It does not involve asking them or prompting them to complete something that is too difficult, but to engage in behavior that is similar to that they’ve already emitted.  It relies solely on successes.  Identifying approximations to a terminal behavior and using extinction and reinforcement can produce big changes through reinforcement of little steps!