PECS, or the Picture Exchange Communication System, is a structured method for teaching functional communication to people who have limited or no speech. It was developed by Andy Bondy and Lori Frost through Pyramid Educational Consultants and designed specifically for children with autism and related developmental disabilities. PECS is rooted in applied behavior analysis (ABA) principles, which is why it comes up so frequently in ABA therapy settings.
How PECS Works
The core idea behind PECS is simple: a learner hands a picture to a communication partner in exchange for something they want. That physical exchange is the foundation of the entire system. Unlike other communication approaches that rely on pointing, eye contact, or imitating speech sounds, PECS teaches the learner to initiate communication on their own by picking up a picture card and giving it to someone.
This matters because initiation is one of the biggest challenges for children with autism. Many kids can learn to respond when prompted, but spontaneously asking for something they need or want is a different skill entirely. PECS builds that skill from the very first lesson.
The system uses a communication book, typically a small binder with Velcro strips inside. Picture cards representing objects, actions, or concepts are stored on the pages. A removable sentence strip along the bottom of the book lets the learner build simple phrases as they advance through the program. Books come in several sizes, from a standard 10¼” x 9¼” binder for beginners down to a pocket-sized 4″ x 5″ version that older or more advanced users can carry throughout the day.
Why PECS Is Considered an ABA Intervention
PECS isn’t just a set of picture cards. It’s built on the same behavioral principles that drive ABA therapy: reinforcement, prompting, prompt fading, and systematic error correction. Every phase of PECS uses these strategies deliberately.
When a child hands over a picture of a cookie and immediately receives a cookie, that’s positive reinforcement. The exchange itself is shaped through physical prompting (a second adult gently guides the child’s hand at first), and those prompts are faded as the child gains independence. When the child picks the wrong picture, therapists use a structured four-step error correction procedure: modeling the correct choice, prompting a practice exchange, switching briefly to a different activity, and then repeating the original opportunity. This isn’t improvised. Every step follows a specific behavioral protocol.
This tight connection to ABA principles is why PECS training is so common in ABA programs and why Board Certified Behavior Analysts (BCBAs) often oversee its implementation.
The Six Phases of PECS
PECS is taught in six progressive phases, each one building on the skills learned before it. The phases move from basic exchanges to constructing sentences.
- Phase 1: How to communicate. The learner picks up a single picture card and hands it to a communication partner, who immediately provides the requested item. Two adults are involved at this stage: one to receive the card and one to physically prompt the exchange from behind. No verbal prompts like “What do you want?” are used, because the goal is self-initiated communication.
- Phase 2: Distance and persistence. The learner practices the same exchange but now has to travel farther to reach the communication partner or the communication book. This teaches persistence and generalizes the skill beyond a tabletop setting.
- Phase 3: Picture discrimination. For the first time, the learner must choose between multiple pictures. This is where the four-step error correction procedure becomes critical, because selecting the right picture from a set of two, then five, then more is a significant cognitive step. Discrimination can be one of the most challenging parts of PECS training.
- Phase 4: Sentence structure. The learner begins building short sentences on the sentence strip, typically starting with “I want” followed by a picture of the desired item. The communication partner reads the strip aloud, which exposes the learner to spoken models of their request.
- Phase 5: Responding to questions. The learner practices answering “What do you want?” by constructing the same sentence strip. This phase teaches responsive communication alongside the self-initiated requesting already established.
- Phase 6: Commenting. The learner expands beyond requesting to make comments about their environment, using sentence starters like “I see,” “I hear,” or “I have.” This is the most advanced phase and moves the learner toward using language socially, not just to get things.
Most learners don’t zip through all six phases quickly. Progress depends on the individual, and some children may spend weeks or months in a single phase before the team decides they’re ready to move on.
Does PECS Help Children Develop Speech?
One of the most common concerns parents have is whether using pictures will replace the motivation to talk. The short answer: PECS does not appear to prevent speech development. But the research on whether it actively promotes spoken language is mixed.
A meta-analysis covering eight single-subject experiments and three group studies found that PECS produced small to moderate gains in communication skills for children with autism ages 1 through 11. Gains in actual spoken speech, however, were small to negative. That doesn’t mean children got worse at talking. It means PECS reliably improves a child’s ability to communicate functionally (requesting, commenting, responding), but it shouldn’t be expected to serve as a speech therapy replacement on its own.
Phase 4, where the communication partner reads the sentence strip aloud, has been identified as a potentially influential point for speech outcomes. The repeated exposure to spoken models during this phase may support vocal development in some children. But the evidence is still emerging, and the primary purpose of PECS is functional communication, not speech production.
PECS Compared to High-Tech Devices
Parents and therapists sometimes weigh PECS against speech-generating devices (SGDs), which are tablet-based apps or dedicated devices that produce spoken words when the user taps icons on a screen. Research comparing the two approaches for building initial requesting skills found no significant difference in effectiveness. Both PECS and SGDs produced increases in requesting behavior across participants.
The practical differences come down to context. PECS requires no batteries, no Wi-Fi, and no troubleshooting. A binder with picture cards works in the rain, at the park, and in a swimming pool. Speech-generating devices offer audible output, which gives the learner a “voice” that unfamiliar communication partners can understand immediately. Many children eventually use both, starting with PECS to build foundational exchange skills and transitioning to or supplementing with a device later.
One consistent finding across studies is that picture discrimination (choosing the right icon from many options) can be challenging regardless of whether the pictures are on cards or on a screen. The difficulty is cognitive, not format-specific.
Who Uses PECS
PECS was originally designed for young children with autism who have little or no functional speech. In practice, it’s now used across a broader range of ages and diagnoses, including intellectual disability, Down syndrome, and other conditions that affect communication. The system works for anyone who can physically pick up and hand over a card, which makes it accessible to learners with a wide range of motor abilities.
It’s most commonly introduced in early intervention settings (ages 2 to 5), but older children, teens, and even adults use PECS when other communication methods haven’t been successful. The system is designed to be used everywhere the learner goes: home, school, therapy sessions, and community outings. Consistency across settings is one of the biggest factors in whether PECS training generalizes into everyday life, and research has flagged maintenance and generalization as areas that require deliberate attention from the therapy team.