How Are Picture Exchange Communication Systems Used in ABA Therapy?

If you’ve ever watched a child point to a picture card to ask for a snack, a toy, or a break, that’s PECS in action. For families of nonverbal children with autism, this simple exchange can feel like a breakthrough. It’s often the first time a child communicates intentionally and independently, and that moment is a big deal.
PECS isn’t just a set of picture cards. It’s a carefully sequenced training protocol with six distinct phases, each building on the last. Here’s what you need to know about how it works, who it’s for, and how ABA therapists use it.

What Is a Picture Exchange Communication System?

A picture exchange communication system (PECS) is an augmentative and alternative communication (AAC) approach that teaches individuals to communicate by handing a picture or symbol to a communication partner in exchange for a desired item, activity, or response.
PECS was developed in 1984 by Andy Bondy, PhD, and Lori Frost, MS, CCC-SLP, at the Delaware Autistic Program. The teaching protocol draws directly from B.F. Skinner’s behavioral analysis of verbal behavior, particularly his concept of the mand, a request made to get a specific outcome. The core idea is that successful, independent communication can be built through systematic prompting and reinforcement strategies, without requiring a child to have any existing speech or imitation skills first.
That last part matters. Unlike some other communication approaches, PECS doesn’t require a child to be able to imitate sounds or words before getting started. This makes it accessible to many individuals with limited or no verbal communication.

Who Can Benefit from PECS?

PECS was originally designed for young children with autism spectrum disorder (ASD) who had little to no functional speech. Over time, it’s been successfully used with a much broader population, including older children and adults with ASD, individuals with developmental disabilities like Down syndrome, people with cerebral palsy affecting speech, children with apraxia of speech, and individuals with acquired communication disorders.
The typical starting profile is someone who doesn’t yet communicate functionally, meaning they’re not reliably using speech, signs, or other methods to make requests and share information. PECS is designed to fill that gap. If you’re exploring options for a nonverbal child, our guide to strategies for encouraging a nonverbal child to communicate covers several complementary approaches worth knowing about.
It’s worth noting that PECS isn’t intended to replace speech. Research has consistently shown that many children who use PECS actually develop more spoken language over time. The communication practice and reinforcement built into the program appear to support, rather than hinder, natural speech development.

The Six Phases of PECS

This is the heart of the program. PECS isn’t just handing a child a binder of picture cards. It’s a structured six-phase training sequence, each with its own teaching procedures and criteria for moving forward.

Phase 1: How to Communicate

The goal of Phase 1 is simple: teach the child that handing a picture to someone leads to getting what they want. Two trainers are typically involved, one serving as the communicative partner and the other as a physical prompter behind the child.
The child sees a highly motivating item. When they reach for it, the physical prompter guides their hand to pick up the corresponding picture card and place it in the communicative partner’s hand. The partner immediately responds by giving the item and naming it: “Oh, you want the cookie!”
There’s no verbal prompt like “give me the picture” at this stage. The goal is spontaneous initiation, not compliance with an instruction.

Phase 2: Distance and Persistence

Once a child can reliably exchange a single picture, Phase 2 increases the challenge. The child learns to travel to find their communication book, select a picture, and seek out a communication partner, even when that partner isn’t sitting right in front of them.
This phase teaches persistence and generalization. Communication doesn’t just happen at a therapist’s table. It happens across rooms, across settings, and with different people.

Phase 3: Picture Discrimination

In Phase 3, the child learns to choose the correct picture from two or more options. This is where the communication system becomes more flexible and meaningful.
Error correction procedures help the child distinguish between preferred items and non-preferred or unrelated items. By the end of Phase 3, many children can select from a large number of pictures across multiple environments.

Phase 4: Sentence Structure

Phase 4 introduces the sentence strip. Instead of handing over a single picture, the child builds a simple sentence: “I want ___.” They place an “I want” picture on the strip, add the picture of the desired item, and hand the whole strip to the communication partner.
This phase builds more complete and grammatically structured communication. It also sets the stage for expanding vocabulary and requesting a wider range of things.

Phase 5: Responsive Requesting

Up until Phase 5, the child has been initiating requests spontaneously. Now they learn to answer the question: “What do you want?” This might sound simple, but it’s actually a new skill. Responding to a verbal prompt is different from initiating on your own.
Phase 5 specifically teaches the child to respond to direct questions, expanding their communicative repertoire to include both spontaneous requests and prompted responses.

Phase 6: Commenting

Phase 6 takes PECS beyond requesting. The child learns to comment on their environment by answering questions like “What do you see?” and “What do you hear?” using sentence starters like “I see,” “I hear,” and “I have.”
This is a significant shift. Communication is no longer just about getting things. It’s about sharing observations, which is a foundational social communication skill.

How ABA Therapists Implement PECS

PECS is implemented within the broader framework of ABA therapy, and Board Certified Behavior Analysts (BCBAs) play a central role in ensuring its effective implementation.
First, the BCBA conducts a preference assessment to identify what items and activities are most motivating for the individual. This matters because PECS relies on motivation. If the child doesn’t really want what’s on offer, there’s no reason to communicate for it.
From there, the BCBA designs the training protocol, selects pictures (real photographs may work better than icons for younger children, depending on individual needs), and trains the adults who will be implementing the system, including parents, teachers, paraprofessionals, and other therapists. This process works hand in hand with functional communication training, another ABA-based approach often used alongside PECS to replace difficult behaviors with meaningful communication.
Data collection is ongoing throughout all six phases. The therapist tracks the child’s accuracy, independence, and spontaneous initiations at each phase to determine when they’re ready to move forward. This data-driven approach is one of the hallmarks of ABA-based intervention.
Generalization is also a major focus. Skills learned in a therapy session need to show up at home, at school, and in the community. ABA therapists work deliberately to help the individual use PECS across settings and communication partners.

PECS vs. Other AAC Options

PECS is one of several augmentative and alternative communication approaches used in ABA therapy. It’s helpful to understand how it compares to other options, even if PECS is often the starting point for many nonverbal individuals.
Speech-generating devices (SGDs), such as apps like Proloquo2Go on an iPad, are increasingly popular and offer voice output that PECS doesn’t. Some research suggests that for certain individuals, high-tech AAC may lead to faster communication gains. PECS, on the other hand, doesn’t require any technology and can be implemented anywhere with just a binder and picture cards.
Sign language is another option, but it requires a communication partner who knows the signs, which limits who the individual can communicate with. PECS picture cards are more universally interpretable. Visual supports in ABA, including schedules, labels, and choice boards, often work alongside PECS as part of a comprehensive communication plan.
In practice, many individuals use a combination of approaches. A child might use PECS in school while also using a speech-generating device at home. The goal is always to find what works best for the individual, and that decision should be made in collaboration with a qualified BCBA and speech-language pathologist. The Pyramid Educational Consultants, founded by PECS creators Andy Bondy and Lori Frost, offer formal PECS training and resources for practitioners and families.

Frequently Asked Questions

How long does PECS training take?

There’s no fixed timeline. Some individuals progress through all six phases in a few months, while others may spend more time at certain phases. The pace depends on the individual’s current communication skills, how frequently PECS is practiced, and how consistently it’s implemented across settings.

Can PECS be used at home?

Yes, and home implementation is strongly encouraged. The more opportunities a child has to use their communication system throughout the day, the faster they tend to progress. ABA therapists typically train parents and caregivers to use PECS correctly so the child gets consistent practice outside of therapy sessions.

Does using PECS prevent a child from developing speech?

No. Research suggests the opposite is often true. Multiple studies have found that children who use PECS frequently develop more spoken words over time. The reinforcement of communication through PECS appears to support natural speech development rather than replacing it.

Who provides PECS training?

PECS training is typically led by a BCBA or a speech-language pathologist with PECS training. Many practitioners pursue formal PECS training through Pyramid Educational Consultants, the organization founded by PECS creators Andy Bondy and Lori Frost.

Is PECS only for autism?

No. While PECS was originally developed for individuals with autism, it’s been used successfully with anyone who has limited functional communication, including people with Down syndrome, cerebral palsy, apraxia of speech, and other developmental or acquired conditions.