Friday, September 7, 2012

An Overview of Discrete Trial Teaching (DTT)

     There are many different ways to teach skills and concepts to children. There are whole group, small group, and individualized strategies. While some are better for teaching certain types of content, one method that is very useful for teaching skills in an inductive way is through discrete trial training (DTT).

     DTT is typically done one-to-one with an instructor and a child in a very structured environment. The clinician contrives the learning environment very intently. Some general examples of these environmental manipulations may be to minimize distractions for acquisition targets, or have distractions present to check for mastery of skills and/or generalization.

     By generalization, it is meant that the skill or behavior is emitted under numerous conditions and across people and settings and materials. For example, if a target skill is to expressively identify a car, a clinician may start with basic pictures of cars, then use Matchbox cars. To oversimplify the concept of generalization, the goal is that the learner is able to understand that there are multiple examples of cars, but they are all still cars. Being able to identify multiple examples of cars can then lead to greater understandings about cars and the world in general, such as that cars drive on the road, but so do buses, and buses carry children to school, so on and so forth. Essentially, we want to make the child’s world larger, and a good way to ensure this is happening is by checking for generalization of skills and behaviors across examples and settings and people.

     Each trial in a DTT sequence is documented on a data sheet for correct and incorrect responses. When an incorrect response is given, we mark the level of prompting (vocal, gestural, model, physical, to name a few) necessary for the child to respond correctly. We then go into the next trial for the same target, to see if learning has occurred. As we move through the trials, the prompt is faded out; however, after 2 incorrect responses, the clinician typically goes into an errorless teaching format. 

     In errorless teaching the learner is fully prompted to respond, thereby not allowing for an opportunity to respond incorrectly.  We run the errorless procedure 3 times, and then run what is termed a transfer trial – or a trial that allows the learner respond independently – to check if learning has occurred. 

     DTT as a teaching protocol is not without some controversy. Some people claim it leads to rote responding, or creates mechanical like responding. However, in light of this criticism, one ought to ask themselves if it would be better to have the child not learning at all? Additionally, through checking for generalization, we ensure that rote responding is decreased. DTT is specialized in that it creates learning opportunities for children who may not have the prerequisite skills for larger group based instruction. With this in mind, DTT can therefore be useful for getting children to the point where they are available for more natural, group based instruction. 

     DTT is extremely useful because it has the learner practicing the skill or behavior with individualized support and opportunities for incorrect responding are lessened, thereby increasing the rate of learning.

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