Discrete trial training, also known as massed trials, is the basic instructional technique of ABA or Applied Behavior Analysis. It is done one to one with individual students and sessions can last from a few minutes to a couple of hours a day.
ABA is based on the pioneering work of B. F. Skinner and developed as an educational technique by O. Ivar Loovas. It has proven to be the most effective and only method of instructing children with autism recommended by the Surgeon General.
Discrete trial training involves presenting a stimulus, asking for a response, and rewarding (reinforcing) a response, starting with an approximation of a correct response, and withdrawing prompts or support until the child can give the response correctly.
Joseph is learning to recognize colors. The teacher/therapist puts three teddy bear counters on the table. The teacher says, "Joey, touch the red bear." Joey touches the red bear. The teacher says, "Good job, Joey!" and tickles him (a reinforcer for Joey).
This is a very simplified version of the process. Success requires several different components.
Discrete trial training is done one to one. In some ABA clinical settings, therapists sit in small therapy rooms or in carrels. In classrooms, it is often enough for the teacher to place the student across a table with his or her back to the classroom. This, of course, will depend on the student. Young children will need to be reinforced for merely sitting at the table learning to learn skills and the first academic task will be the behaviors that keep them at the table and help them focus, not only sitting but also imitating. ("Do this. Now do this! Good job!)
Reinforcement is anything that increases the likelihood a behavior will appear again. Reinforcement occurs across a continuum, from very basic, like preferred food to secondary reinforcement, reinforcement that is learned over time. Secondary reinforcement results as a child learns to associate positive outcomes with the teacher, with praise, or with tokens that will be rewarded after accumulating the target number. This should be the goal of any reinforcement plan, since typically developing children and adults often work hard and long for secondary reinforcement, like parental praise, a paycheck at the end of the month, the regard and esteem of peers or their community.
A teacher needs to have a full quiver of edible, physical, sensory, and social reinforcers. The best and most powerful reinforcer is the teacher her or himself. When you dish out lots of reinforcement, lots of praise and perhaps a good measure of fun you will find you don't need a lot of rewards and prizes.
Reinforcement also needs to be delivered randomly, widening the gap between each reinforcer in what is referred to as a variable schedule. Reinforcement delivered on a regular (say every third probe) is less likely to make the learned behavior permanent.
Successful discrete trial training is based on well designed, measurable IEP goals. Those goals will designate the number of successive successful trials, the correct response (name, indicate, point, etc.) and may, in the case of many children on the spectrum, have progressive benchmarks that go from simple to more complex responses.
Example: When presented with pictures of farm animals in a field of four, Rodney will point to the correct animal requested by the teacher 18 out of 20 trials, for 3 consecutive probes. In discrete trial training, the teacher will present four pictures of farm animals and have Rodney point to one of the animals: "Rodney, point to the pig. Good Job! Rodney, point to the cow. Good job!"
Massed or Interspersed Tasks
Discrete trials training is also called "massed trials," though this is actually a misnomer. "Massed trials" is when a large number of a single task are repeated in quick succession. In the example above, Rodney would just see pictures of farm animals. The teacher will do "massed" trials of a single task, and then start "massed" trials of a second set of tasks.
The alternate form of discrete trial training is interspersal of tasks. The teacher or therapist brings several tasks to the table and asks the child to do them alternately. You might ask a child to point to the pig, and then ask the child to touch his nose. Tasks continue to be delivered quickly.