What is Discrete Trial Teaching?
Discrete Trial Teaching (DTT) is a basic teaching strategy usually completed as a table-based activity with a “teacher” and a “learner”. The teacher selects the skill to develop, for example “identifying fruit”. This skill is then broken into smaller teaching opportunities. In a session you have multiple trials, each trial will have a clear start and finish. The number of trials in a session will vary depending on the learner. The number of trials may be pre-determined but it is also important to assess assent throughout the session. If the learner stops engaging with the trial or presents indicators that they are no longer happy to engage (no longer giving assent) then the teacher should end the trial in a positive way.
Setting up a DTT session
Establish what the teaching goal is and prepare your materials. Where possible try to complete the DTT sessions in a clear environment, limiting any distractions. A clear prompting hierarchy will need to be established, which will be individualised to the learner. It is also important to program in fading the prompts. You will need to establish what reinforcement will be given for a correct response. In some cases, you may also need to provide an additional reinforcer at the end of the DTT session. You may want to look at combining this with a Token Economy system. If an incorrect response is given, corrective feedback will be given. You may look at errorless learning during the DTT to avoid incorrect responses, this may be providing prompts immediately and or blocking incorrect responses. You will also need multiple exemplars to promote generalisation of the skill.
Topics to teach during a DTT session
There are various skills that can be taught during a DTT session such as:
· Social skills
· Academic skills
· Imitation
· Match to sample
· Receptive identification
· Expressive identification
Example session
Setting:
Table with two chairs opposite each other
Box with your materials
If tangible reinforcers are used place in a box out of sight of the learner but within easy reach of the teacher
Prepare your stimuli: This may be pictures or tangible items
Trial 1: Present the array, this will include the correct response and two distractors. It is important to gain the learners attention before presenting the instruction. Once you have gained the clients attention present the instruction. This should be brief, for example “touch banana”. Wait for the learner to respond (usually 5-10 seconds but this will vary from learner to learner). If the learner does not respond you will need to provide a prompt, such as a model prompt. Or, if you are using errorless learning immediately provide a prompt after the instruction. When the learner provides the correct response the teacher will provide praise, this may be a verbal praise “good touching banana” which may also be paired with a “high five”. This is then repeated moving the order of the array each time. The learner moves on to a new target once they have reached mastery.
Example Array:
It is important to program for generalisation, sticking with our “identification of fruit” example, you would use various images of the fruit:
Collecting data
As with any area of ABA is important that we are collecting data to measure the effectiveness of our intervention. The first 3 trials will act as a baseline measure, during these trials you will not provide any prompts or reinforcement for a correct or incorrect response. If your baseline data shows that the individual has not mastered the skill then Discrete Trial Teaching starts. The measurement system for a DTT would be percentage correct or trials to criterion.
Here is an example data sheet:
Evidence base
DTT has a wide range of evidence across various skills. A recent publication looked at the use of DTT to improve employment opportunities for adults with ASD (Hillman CB, Lerman DC, Kosel ML. Discrete-trial training performance of behavior interventionists with autism spectrum disorder: A systematic replication and extension. J Appl Behav Anal. 2021 Jan;54(1):374-388. doi: 10.1002/jaba.755. Epub 2020 Jul 31. PMID: 32734605.)
Adapt Behaviour offer online training on the use of DTT:
Parents: Supporting my child’s communication skills reference number #96385.
Teachers: Making sure no child is left behind #70557.
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