Discrete Trial Format

Discrete trial format also has been used in the intensive behavioral intervention for young children with autism developed by Dr. Ivar Lovaas and often called ABA.  ABA is actually Applied Behavioral Analysis, the natural science approach to studying socially important human behavior. Discrete trials involve repeated trials with very short breaks between trials.  Discrete trial format is sometimes referred to as discrete trial teaching. 

This is how it works:

Before the cue is given, staff determines whether to provide a prompt or not. The prompt is performed with or immediately after the cue. The pause between trials makes it discrete. Remember, individuals with autism need to know when a task begins (cue) and ends (reinforcer or “No,” and the short pause).

My favorite place to use discrete trial teaching is in the bathroom for a chain of behaviors. It is very hard for staff not to speak in this setting, so they unwittingly create verbal prompt dependence. A variety of cues call for language, including, “Pull up your pants,” “Wash your hands,” “Turn on the water,” “Get a towel,” and “Throw it in the garbage.” One way to determine when to use a discrete trial is by noting whether anyone has to tell you to perform a certain task. For example, does anyone tell you to wash your hands after you use the bathroom?

The discrete trial begins as the student enters the bathroom and ends when he leaves it. The cue for the bathroom may be the bathroom itself, the sentence, “Line up to use the bathroom,” or the command, “Go to the bathroom.” Remember, no talking between the cue and when the student leaves the bathroom. Guide the student to a stall and assist physically if necessary with removal of pants. When he is done using the toilet and pulls up his pants, wait to see if he zips before leaving the stall. Cue by pointing to or guiding his hands to his zipper or providing help. If the student does not move toward the sink, point to it or guide him to it. Assist with turning on the water. Demonstrate how to get soap and rub it on hands. Do not speak! Demonstrate or guide rinsing hands. Point to the paper towels and then to the garbage can. You also may demonstrate.

After the student leaves the bathroom, reinforce with praise and/or a special activity. Pat yourself on the back for not speaking. That was truly a difficult experience for those of us who love to talk. What can happen if you speak during this series of activities?

Often we do not realize that we are speaking and that the student is responding to--and actually stuck on--our words. Then we indicate that the student can perform this task independently. However, this is not true since he was being cued during the activity. He goes on to the next grade and cannot use the bathroom independently. The new staff wonder why the student does not turn on the water or get a towel and just stands there. They do not realize that the student is dependent on verbal prompts.

Consider using discrete trial teaching in a variety of settings and to teach a variety of activities, especially daily living skills, because it eliminates the use of words and verbal prompt dependence. A version of discrete trial teaching or Errorless Teaching can be helpful for teaching both expressive and receptive language (Verbal Behavior according to Skinner) --especially verbs; such as touch, show, give, find and point.  The behaviors that these verbs elicit are very similar, yet individuals with autism need to be taught the meaning of each one.

What about individuals with Asperger’s?

I have seen Errorless Teaching used with students with Asperger’s. Be sure to monitor whether the student waits for you to say something before she begins a task. Also, must a student ask you several questions each time before beginning a task?  These may be indicators of prompt dependence.

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