Discrete trial and Applied Behavioral Analysis (ABA) methods are often confused, but they are not identical. Discrete trial is a teaching strategy used under the umbrella that is ABA. Discrete trial is a method of instruction that works to shape behavior using repetition and cause and effect learning. Discrete trial is a "chaining" method that builds one skill on top of another. Complex tasks are broken down into small steps and each step is mastered in turn across a series of trials.
Tasks differ in their complexity. Basic tasks such as being able to sit quietly for an extended period are required for other, more complex tasks such as working with a computer program. Being able to speak the phrase, "hello, how are you" is a requirement for 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). Discrete trial learning methods recognize this progression of tasks and attempts to teach more basic type tasks first.
A typical starting task for discrete trials work is to be able to simply sit at a workstation. The directive, "come sit" is often one of the first goals for discrete trial students. When students can sit and pay attention to tasks without having a tantrum or becoming aggressive, they are ready to take on more complex tasks. These include social and communication tasks. Communication skills teaching frequently starts with basic skills like learning to make appropriate eye contact, and progresses towards more advanced communication skills, including object labeling and use of sign language to convey needs.
Discrete trial methods are designed to increase the likelihood that children will act in desirable ways. It is not designed to decrease their tendency to act in undesired ways. Children are motivated to act in desired ways through the application of reinforcement techniques. Positive reinforcement happens when behavior is rewarded, such as by providing a desired treat. To be effective, rewards must be presented immediately, and be concrete in nature (visible). Rewards that are abstract, or which are delivered after a delay may not be associated with desired behaviors and may appear to children to have simply been given for no reason. Discrete trial methods never use punishment methods (which involve adding something negative and disliked to the child's environment). However, negative reinforcement methods, which involve rewarding children when they stop doing something undesirable, are used.
In addition to shaping children's behavior towards the learning of social and communicative skills, discrete trial methods also teach children about cause and effect. Students learn that they are expected to respond to trials, and that every response they make will have a consequence. They will either be rewarded for their response or they will not be rewarded. Therapists are ultimately interested in getting children to pay attention to task learning and in developing their ability to respond appropriately to communication. Letters, numbers and object labeling skills are acquired as part of discrete trials training. Because communication skills are basic and fundamental and must be present before more complex social skills can be taught, they are taught early in the process.