The Picture Exchange Communication System (PECS) was developed to help children and adults with autism and other developmental disabilities to rapidly acquire functional communication skills (Bondy and Frost, 1994). The system is primarily used with individuals who either do not use speech or speak with limited effectiveness.
To implement PECS, the powerful reinforcers for which a child will be motivated to communicate should be identified. Teaching strategies use a variety of prompting, shaping, and fading techniques to gradually improve and modify how children use the system. From a communication perspective, the system emphasizes the importance of having children learn to approach their communicative partner from the beginning of training rather than solely waiting for specific cues from the partner. The training sequence in PECS relies upon understanding the fundamental issues associated with communication and autism.
The first step entails how to spontaneously request items or activities. The first step, therefore, is to identify what an individual wants. Once a reinforcer assessment has been completed with a hierarchical listing, PECS can be started. A highly motivating reward must be identified.
Because the initial goal is to teach spontaneous requesting, the tendency to use direct verbal prompts should be avoided. It has been found that the most effective strategy is to use two teachers to start training. One trainer entices with the identified reinforcer and the other trainer stays behind the student, waits for a reach toward the reinforcer, and physically assists in picking up and giving the picture. As quickly as possible, these physical prompts are faded. When the teacher enticing receives the picture, the child immediately receives the reward, along with an appropriate comment from the teacher.
Once a child can reliably exchange a single picture, training immediately shifts into promoting greater spontaneity, persistence, and generalization. The child is taught to move greater distances to get to a partner, move further to get to the picture, and to request in various environments (i.e., different rooms, settings, etc.) with different people about different reinforcers. During these initial phases, no choice between pictures is required. Discrimination training is conducted when a persistent communicative response has been demonstrated. This sequence parallels typically developing children who learn to approach parents, look and gesture about various events prior to having distinct messages, and prior to developing a spoken vocabulary.
The third phase of training involves making choices between symbols. This phase may result in significantly different acquisition rates because some children begin with a strong history of visual discriminations while others begin needing to master visual discrimination of symbols. Some children who have displayed difficulty with traditional matching-to-sample formats perform much better with discrimination of pictures within a requesting format.
Once a fundamental discrimination repertoire is demonstrated, the training focuses on developing sentence structure. Very young children who develop typical speech use intonation and other variations to help listeners understand when they say "ball" as a request as opposed to a comment. Intonation should also be addressed to clarify whether the single picture they give is a request or a comment. First, it is necessary to modify how children request by teaching them to use a simple sentence constructed with an icon representing "I want" and a picture of what is wanted. Both are placed upon a sentence-strip that is still handed to the partner. The training sequence also teaches children to respond to the simple question "What do you want?" with a strong recommendation to monitor that spontaneous requests are still occurring at a reasonable rate.
Frost, L. & Bondy, A. (1994) The Picture Exchange Communication System Training Manual. Cherry Hill , NJ : PECs, Inc.
Frost, L. & Bondy, A. (1998) The Picture Exchange Communication System: An Introductory Videotape. Cherry Hill, NJ: PECs, Inc.
