Discrete trial training (DTT) is a highly-structured training technique that involves a trainer instructing an individual on the autism spectrum using a series of learning opportunities or ‘trials’. Each ‘trial’ has a definite beginning and end, which is why the trials are described as ‘discrete’.
The trainer begins each trial with a short, clear instruction or a question. The trainer may also prompt the learner, showing him how to respond correctly to the instruction or question. For example, the teacher may hold up a picture of a ball and say ‘What is this? Ball’. She may then repeat the question with or without the answer in order to encourage the learner to say ‘Ball’.
If the learner does what the trainer wants, she will immediately reward him. For example, she may praise him or allow him to have something he wants, such as the ball. If the learner does not do what the trainer wants, she will repeat the instruction or try a slightly different approach. In order to be effective the rewards must be tangible and be given to the learner immediately. Otherwise the learner may not associate them with the behaviours being taught.
Discrete trial training allows the trainer to break complex tasks down into smaller, simpler steps, each of which can be repeated until it is mastered. Complicated skills can be built, or ‘scaffolded’, on simpler ones. For example, the trainer may teach the learner how to say "hello, how are you" before teaching him more complex social communication tasks such as greeting someone (which may also involve making eye contact, and paying attention to what the other person has to say).