Picture Exchange Communication System (PECS) is a system that is used as a functional communication tool, for children with Autism and limited communication abilities. This communication system is often in place of verbal behavior and can, in some cases, help increase verbal behavior. “PECS has been proved to facilitate functional communication, improve severe impairments of functional speech, decrease the behaviors problem;” however, only a few studies have shown positive effects in the social aspect (Lerna et al., 2012).

PECS is a commonly used Alternative and Augmentative Communication system (AAC) among children with Autism, or children with limited speech ability (Chua & Poon, 2018).   It was first developed in 1985 by Lori Frost, a Speech Language Pathologist, and Dr. Andrew Bondy, from Delaware Autistic Program, in order to teach functional communication people with developmental delay, and language impairments (Chua & Poon, 2018).  According to Chua and Poon (2018), these clients, regardless of communicative level, don’t engage in spontaneous communication as often as typically developing children. People with Autism are more likely to need verbal, or physical, prompting and modeling (Chua & Poon, 2018).

PECS is taught in six phases and eliminates verbal prompts during early teaching phases(Chua & Poon, 2018).   A prompt partner is added, to help guide the child through the steps, transitioning from full, physical, hand-over-hand prompting, to a gestural prompt. This process is to prevent the client from being dependent on prompting. The learner will learn to initiate communication because the communication partner will withhold attention, and praise, until the learner exchanges the icon (Chua & Poon, 2018).

According to Chua and Poon (2018), the learner is taught to exchange the icon first, to increase spontaneous communication. After this is mastered, the learner is taught to discriminate between non-preferred items and highly-preferred items, and then, multiple high-preferred items. This method of alternative communication doesn’t require fine motor skills to communicate, like sign language does (Chua & Poon, 2018).

It has been proven that age, severity of Autism symptomology, and the level of mastery doesn’t predict spontaneous PECS use. This protocol is beneficial for all learners with Autism (Chua & Poon, 2018). Chua and Poon (2018), conducted a study, to determine the child characteristics that predict spontaneous PECS use, the teaching factors that predict spontaneous PECS use, and context in which PECS is taught being a predictor for spontaneous PECS use. This study determined the way PECS is taught has a correlation with more spontaneous communication (Chua & Poon, 2018).

Historical Overview

Picture Exchange Communication System (PECS) is a trademarked program of Pyramid Educational Products, which was founded by Andy Bondy, PhD, and Lori Frost, MS, CCC-SLP. Frost and Bondy developed this program in 1985, to help children with Autism communicate their desires. (Pyramid Education Consultants, 2020).

PECS was first implemented with preschool students with Autism at the Delaware Autism Program, by Dr. Bondy and Frost (Pyramid Educational Consultants, 2020). According to Pyramid Educational Consultants, the founding organization of PECS, PECS is implemented worldwide, and with thousands of people with various ages and cognitive, physical, and communication challenges (Pyramid Educational Consultants, 2020).

The PECS program is based on the book, Verbal Behavior (1957), by B.F. Skinner. This book focuses on broad spectrum applied behavior analysis. Each of the 6 phases of PECS is a visually presented method to teach children to communicate, with ideas broken down into small teachable and systematic steps. Some of the clients using PECS can develop speech, while others may transition to devices that generate speech for them (Skinner, B.F., 1957).

The history and development of PECS is similar to how it is used today.  There has been more research done recently, to prove that the implementation of PECS can help learners that need a method of functional communication (Travis & Geiger, 2010).

Theoretical Underpinnings

The topic is conceptually systematic with behavior analysis because it encompasses the seven dimensions of behavior analysis. The Picture Exchange Communication System (PECS) has been proven to generalize, across settings and people (Greenburg et al., 2012).  Four children with Autism were studied, for the effects of generalization of PECS. The children generalized PECS communication to the home setting, with parents; the community, with a stranger; and a new playroom, with a therapist. This indicates that, once a learner is taught through the PECS protocol, it can be generalized, to different settings and communication partners (Greenberg et al., 2012).

The effectiveness of PECS has been studied in the results of requesting. PECS is proven to be effective for children in requesting items, and this suggests that it is highly effective for learners who have Autism (Travis & Geiger, 2010). Two children with limited language use, and some spoken language, were taught to use PECS, to communicate. During this study, length of utterance, and frequency of requests, were evaluated, in structured and unstructured settings, in four phases: pretraining, training, post-training and follow-up. PECS was proven to be an effective functional communication tool, within this experiment (Travis & Geiger, 2010).

The technological aspect of PECs is the use of a handbook, for the summary of the process. This handbook includes each phase of PECs and how to implement PECS protocol, along with helpful hints to complete the phases, and tailor it to each specific client (Pyramid Educational Consultants, 2020). These tactics are to uphold that fidelity of PECS, and keep implementation consistent across clients and implementors (Pyramid Educational Consultants, 2020).

The goal of PECs is to provide those with little-to-no communication with a functional way to communicate their wants and needs. PECS is applied in the field and serves the purpose of functional communication for many clients (Pyramid Educational Consultants, 2020).

As previously stated, PECS is based on the book, Verbal Behavior (1957), by B.F. Skinner, which is why it includes behavior analytic steps, and reinforcement into the program, for the use of early learners (Pyramid Educational Consultants, 2020). This is conceptually systematic, as behavior principles are used–specifically, the use of prompts–in order to gain independence of requesting. Verbal prompts are never included, in order to reduce the possibility of generating prompt dependence. Gestures and physical prompts are used, to increase independent initiation, and reduce error throughout the teaching process (Pyramid Educational Consultants, 2020). The protocol of PECS includes an error correction sequence that is specific to PECS to promote learning, even if errors occur (Pyramid Educational Consultants, 2020).

The functional relationship between the behavior and environment, to give access to what the client wants, determines that it is analytic in nature. The implementation being analytic is the 6th dimension to behavior analysis. Picture Exchange Communication System(PECS) involves a behavior being completed to request for the item needed, which concludes that it is behavioral in nature (Pyramid Educational Consultants, 2020).

Implementing PECS

According to Dr. Andy Bondy, it is essential to understand what functional communication is, when looking at Picture Exchange Communication System. Functional communication from a behavioral perspective, as discussed previously, comes from B.F. Skinner, and his book, Verbal Behavior (1957). Skinner discusses the use of a speaker and listener in communication, and their role within the exchange. A listener is required to mediate reinforcement for the speaker, which, therefore, is a social aspect (Skinner, 1957).  Teaching a learner how to label and mand for items independently is crucial; that learner needs the stimulus control, not to be under a question or a prompt (Skinner, 1957).  Communication should be natural and occur within natural contingencies. According to Dr. Bondy, responding to questions is a completely different control, versus initiating communication, labeling items or asking for items. The key idea for this control theory is that some kids can become prompt dependent, and need the question, and imitation, to respond. If tactics of verbal prompts, or physical prompts, must be used, Dr. Bondy explains the importance of fading them quickly, to limit prompt dependency. In the case of overcoming prompt dependence, incidental teaching was developed, to increase independent communication (Bondy, 2001).

Lori Frost and Dr. Bondy observed clients having difficulty learning, and using, language with current methods, such as sign language, and speech. PECS became an idea after teaching kids the use of picture-based systems. Pointing to the items on a communication board was successful with many children, and adults, with delays, including speech production, according to Dr. Bondy (2001).  Although this method of communication was effective for some, people with Autism seemed to struggle selecting an item off the board (Bondy, 2001). Dr. Bondy believed that this method of communication was teaching children to affix themselves to the board, instead of the person they were communicating with. The board method suggests the communication was not under stimulus control of the communication partner, and prompt dependency was likely to follow (Bondy, 2001). Dr. Bondy stated that his goal, when writing the first step of PECS, was to develop a rapidly-used response, that would be a form of functional communication (Bondy, 2001).

The first step in using PECS as functional communication is doing a preference assessment (Bondy, 2001). You need to know what the child wants before you show it or help them ask for it. During this process, it’s the educator’s job to make sure the child has multiple different items, and does not limit themselves to a few. If the therapist limits the child to food or drinks, then the child will only know how to ask for food or drinks, which will limit the benefits of this functional communication tool (Bondy, 2001). Dr. Bondy emphasizes that teachers should use establishing operations to teach various reinforcers. The items that are taught within the functional responses should be items the client will typically ask for (Bondy 2001).

Teaching the client is an important component of using this functional communication tool. The effectiveness of PECS depends on the implementation (Bondy, 2001). The child, in the beginning, will need assistance, to learn how to respond when they want an item. As previously mentioned, Dr. Bondy uses a “prompt partner,” during the first couple stages of PECS. This person stays as invisible as possible and prompts the child from behind. No words are used during this prompt sequence, all the while the communication partner is silently enticing the child with the item (i.e. showing them the item, playing with it). The prompt includes hand-over- hand, prompting the client to complete the exchange sequence, in order to receive access to the item.

The first phase of PECS includes the child reaching for an icon, and exchanging it with their communication partner (Bondy, 2001).  Dr. Bondy compares this phase to the first use of language by children who are verbal. Before learning what words mean, children use words, or sounds, consistently. This is the same idea PECS follows; the child must exchange the icon for that item, regardless if they don’t know what the picture is of. Initiating conversation is taught before discrimination (Bondy, 2001).

After the initial exchange phase is mastered, the child  moves into distance, and persistence, of PECS: increasing distance; resistance to extinction; increasing the variety of reinforcers used; and conditions of the exchange (i.e. room, teachers) (Bondy, 2001). Generalization is taught, throughout the phases of PECS and the protocol. While the client continues to work on generalization, more techniques and steps are added, to increase the difficulty, and capability of the client to communicate (Bondy, 2001).

Following distance and persistence phase, the child will start discrimination training (Bondy, 2001). The difference in this phase, from the previous, is the child is not only exchanging a picture; they also must exchange the picture that corresponds to the item they are wanting. In this case, you must do a reinforcer assessment, and assess if the items considered low preferred, are truly low-preferred, for the client.  Reinforcement still occurs immediately after the exchange; the teacher gives the client what they asked for (Bondy, 2001). If the low-preferred item was chosen, the teacher hands it to the client, but the client should provide some kind of negative reaction. This is when you start the error correction sequence, and the client learns what the icons mean. The error correction sequence includes pointing to the correct icon; holding the icon next to the item; showing the client; replacing both icons on the book; and then, performing a distractor (i.e. mastered task, or flipping the book over). The client is then allowed to request the item again. If they error again, error correction is used, up to two more times (Bondy, 2001). Following the third error, the client is then given the communication book, with only the preferred item on the front, so they can only ask correctly. If the client exchanges the right icon at any point independently, they are given the item, and lots of verbal praise (Bondy, 2001).

Once discrimination of icons between high and low preferred is mastered, the client will learn to discriminate between highly preferred items (Bondy, 2001). This incorporates the use of a correspondence check. The client must exchange the icon, like previous phases, but also must remove the item, in an array of objects. This tactic is to ensure the client knows what they are asking for and can discriminate between the physical objects. A correspondence check involves the communication partner holding up the items and saying, “take it,” prompting the client to take one of the items. If the client takes the correct item, reinforcement is immediately given.  If the client takes the other object, an error correction sequence, similar to the previous, is conducted. (Bondy, 2001).

The sentence strip phase teaches clients to use sentences when requesting items. The use of sentence starters such as: “I want;” “I see;” “I hear;” serve a function in communication (Bondy, 2001).  When first teaching this phase, backward chaining is implemented. A sentence strip is affixed to the bottom of the book, with an icon saying ,“I want,” on the left side. The client must flip through their book and find the item they want, affix it to the sentence strip, and exchange the strip with the partner. When the communication partner reads the strip, the client should touch both icons, as if they were reading the strip themselves. After this step is mastered, the “I want” icon is then moved to the front of the communication book, and the same rules apply to this phase (Bondy, 2001).

After the sentence strip construction is mastered, it is recommended to introduce a fixed time delay, when reading back both the “I want,” and the item (Bondy, 2001).  This would imply the client hands the strip to the partner, and points to the “I want” icon; the communication partner reads the first icon, but when the client points to the reinforcer, the partner waits three-to-five seconds, before saying the item. This is an attempt to increase vocalizations for the client; however, the vocalizations aren’t a requirement, for the client to contact reinforcement (Bondy, 2001).  When this phase is mastered, a time delay is added to both icons on the sentence strip. Differential reinforcement is essential in this part of PECS (Bondy, 2001). When the client vocalizes either step of the sentence strip, they are given more of the item they asked for, along with social praise that exceeds other responses. If the client competes the strip exchange, but doesn’t vocalize, they are given the item in small pieces, and with some praise. The idea of differential reinforcement is to increase the likelihood the client will repeat the verbal requests, without punishing them for not vocalizing (Bondy, 2001).

Following the fourth phase of PECS, there are two routes implementers can go. The first route includes commenting, and the second includes descriptive vocabulary (Bondy, 2001).  Commenting starts by the implementer using the phrase, “What do you want?”. This phrase is taught in a prompt phase, where the implementer points to the “I want” icon on the front of the book, while simultaneously saying the phrase, “What do you want?”. This prompt shows the child what the question is asking, by telling them how to respond to the question (Bondy, 2001). Over time, the implementer increases the prompt delay, and eventually, the goal is for the child to answer the question independently, and beat the prompt from the implementer (Bondy, 2001). Next, within the commenting phase, the child is commenting on items in the environment. To teach this phase correctly, you must start with commenting on items that are not reinforcing for the client; this is the opposite of the first phase of PECS (Bondy, 2001). Typically commenting on items that are not reinforcing means objects that draw their attention (i.e. an item disappearing from environment). This phase usually begins with the implementer asking, “What do you see?” while prompting to a new icon on the book. The same delay prompt is used for teaching this as teaching the child to answer with, “I want.” After “see” is taught, the client will then learn hearing, smelling, tasting and touching. The question is also gradually faded within these prompts, so the client will see, and comment on, objects in the environment, independently (Bondy, 2001).

Expanding vocabulary is the other possible route within the 5th phase. This incorporates colors and attributes of objects (i.e. red candy, big cookie, fast car). It is often important to kids to get the big cookie, or a certain color of candy. According to Bondy (2001), it is critical to teach both sides of the attribute. A child might want the big cookie, but they want a small portion of vegetables.

The system of PECS is simple and can be applied in settings that don’t include an implementer, which is a huge benefit (Bondy, 2001).  If the child takes the book with them to a grocery store, and hands the sentence strip to an employee, they can read the strip, and help the person with what they need. The outside community doesn’t need training on this, which gives it strong generalization; however, extensive training is needed to train the learner on using the system (Bondy, 2001).

Another benefit of PECS, according to Dr. Bondy (2001), is that it appears to have a great impact on the development of speech. Dr. Bondy states that, when a learner starts using PECS before age six, or has been using it for longer than a year, and is using 80-120 icons within the PECS system, learners typically come to use speech as their primary method of communication (Bondy, 2001). For clients that don’t develop speech, more icons can be added. After this, Dr. Bondy (2001) makes the recommendation that the learner transitions to an Augmentative and Alternative Communication Device (AAC) (i.e. a type of electronic device that the learner can use to communicate). The social aspect is essential to uphold in this transition to a device, according to Dr. Bondy. The social piece of using a device includes the learner getting the communication partner’s attention, and then using the device to request (Bondy, 2001).

The final benefit that Dr. Bondy discusses is the critical skills taught by implementing PECS. During this protocol, kids learn to ask for help, and for a break (Bondy, 2001). They are also taught a waiting skill that gradually increases, from five seconds, to two minutes. This should be implemented naturally, when the communication partner must go get an item that was asked for, or cook the meal that was requested (Bondy, 2001).

While there are many benefits to PECS, there also can be some challenges. The cards used are typically small, and easy to lose (Bondy, 2001). To combat this, making multiples of the same icons can be helpful to the learner, so they always have opportunity to ask for what they want. The icons are also limited, in the moment, to the item the client likes. If the client gets new toys, or decides they like something new, new cards must be made, and this can be time- consuming, if the right tools aren’t used (Bondy, 2001).

Application

PECS Increases Vocalizations

A general consistence of multiple articles is the increasing effect Picture Exchange Communication System (PECS) has on requesting. Travis and Geiger (2010) included a requesting component in their mixed design, single subject-multiple baseline, across three behaviors, along with commenting, length of utterances, speech complexity, pragmatics, and communication. Two children with autism spectrum disorder, both 9 years old, presented with some spoken language, but limited in the aspect of communication exchange, and had no formal PECS training. The qualitative component within the study included the speech complexity, pragmatics, communication, and parent and educator points-of-view (Travis & Geiger, 2010). The results of this study concluded that the two participants benefitted from PECS: increases in requesting were found, along with mixed results for length of utterances, and commenting. Specifically, significant increases in deliberate communication and requesting were found, for both participants. Both participants exhibited a solid understanding of the PECS protocol, and used clear, thorough, verbal requests by the end of the training. Utterances increased for both participants following PECS phase four; participant one’s utterances increased rapidly, and participant two’s utterance increased, at a gradual rate (Travis & Geiger, 2010). Along with utterances, the study examined clause level, phrases and word endings. The quality of utterances(clauses) increased, from one to two words, to three- or four-word, utterances, following PECS phase 4, for both participants. According to experimenters, the participants showed more determiners, pronouns and adjectives in their speech, following PECS.  The changes in word endings included the use of plurals for one participant, and a decrease of double negatives by the other participant.  This study suggests that students using PECS protocol can increase verbal communication and requests (Travis & Geiger, 2010).

The increase of utterances and speech complexity with the implementation of PECS is also found in another study, within the same parameters (Ganz & Simpson, 2004). The participants in this study were three young children with autism, or developmental delay, who were taught PECS phases one through four. The results concluded an increase in word utterances, complexity of grammar, and words used. This is the same method of study used by Travis and Geiger (2010), using PECs through phase four, and scoring the same aspects. When comparing the two studies, the main difference between the studies was the number of participants, and the ages. Travis and Geiger (2010) used children three years older than Ganz and Simpson (2004), in which maturity could have been an impact on utterances and communication.

Travis & Geiger (2010), implemented PECs phases through four, which is the phase that includes a time delay to help promote vocalizations, and determine the real value PECS has on communication (Bondy, 2001). Conklin & Mayer (2011) discuss the need to implement PECS, through all phases, during their experiment. This specific study sought to use PECs through the whole protocol; however, they determined the rate of acquisition of PECS is different per participant. One participant completed the full PECS protocol, while the other two completed through phase 3. Although, it wasn’t completed fully, Conklin and Mayer (2011) determined that PECS has an increasing effect on communication and initiation, for participants using PECS.

Similarly, a study done by Schwartz et al. (1998) showed increases in some children’s verbal communication, within their experiment.  This article includes two studies–one examining rapid learning of PECS, and the other looking at communicative acts. In the first study, 31 preschool students, ages three to six, were studied. 16 were diagnosed with autism spectrum disorder, and the other 15 participants had been diagnosed with down syndrome, or other developmental disabilities. This experiment concluded that for most children, on average, it will take 14 months to complete the full PECS protocol. This directly correlates with the results and method of Conklin & Mayer (2011), who discuss the varying length of time it takes children to complete the protocol. The second study with Schwartz et al. (1998) examines 18 preschoolers who have developmental disabilities and had previously completed the first experiment on PECS learning. All data for this experiment was collected in two specific settings, using observation of the activity. Observations were for the length of the activity, or until the child completed fifty communicative acts (Schwartz et al., 1998).

Each child was observed 3 times, across a two-school year time span (Schwartz et al., 1998). The observer put the behaviors into codes: gestures, vocalizations, manual signs, PECS, and verbal. Spontaneous speech was examined throughout these observations. The participants were split into two groups: “talkers,” who demonstrated five or more words in the first observations, and “nontalkers,” who demonstrated less than five words (Schwartz et al., 1998). Eight participants were considered talkers, while ten were considered nontalkers.

Results of this study within the natural play setting indicate that “talkers’” average novel and unprompted words went from twelve in the first observation, to twenty-four in the second, and to forty in the third observation. While these numbers are averages, it shows a significant increase in words for these time periods. “Nontalkers,” in a play period, had an average of one novel and unprompted word during the first observation, two in the second observation, and four during the final observation (Schwartz et al., 1998) During snack, the talkers increased, from eight novel and unprompted words; to eighteen in the second observation; then, to thirty-four, in the third observation. “Nontalkers” showed two novel and unprompted words during the first observation, three during the second observation, and three during the final observation. The observations of the group “nontalkers” didn’t increase at a rapid rate, and for this reason, the author suggests that more research be done on the direct correlation PECS has on verbal communication, in individuals that fall within the “nontalker” category (Schwartz et al., 1998).

Across both settings, the children considered to be “talkers” increased, in novel and unprompted words per observation, which suggests a correlation between PECS and verbal communication for those individuals.  However, the “nontalkers” didn’t make significant progress when studying novel words. When putting these studies together, 44% of the participants increased in spoken language, following the PECS protocol (Schwartz et al., 1998).

Both studies discussed previously showed an increase in verbal communication. Although Schwartz et al. (1998) examined specific groups of participants, that were at different levels of communication starting the PECS training, there was a very slight increase in the verbal communication for the “nontalkers” in this study (Schwartz et al., 1998). When assessing this study, the increasing trend line is subtle, but does exist, for this “nontalker” group (Schwartz et al., 1998).

A single case research study by Khuansuwan and Kummuang (2014) includes six participants, ages six-to-nineteen, with PECS phases one through three. This case study determined that PECS has an effect on communication: scores rose, from an average of 3.83 utterances per session, to 6.83 utterances per session, after the program of PECS was implemented. These results show a slight increasing trend in utterances, similar to the “nontalker” group of participants in the previous study. While the increase is subtle, it shows an increase in vocalizations and utterances, after implementing PECS (Khuansuwan & Kummuang 2014).

A meta-analysis conducted by Hart and Banda (2010) included 13 single subject studies to determine the effectiveness of PECS, the effect it has on speech and behavior, generalization beyond training, and social validity of the intervention. This study, along with previous studies, has shown a correlation between PECS protocol use, and an increase in verbal ability (Hart & Banda, 2010).

Similar to the study done by Schwartz et al. (1998), the participants were put into categories, based on their verbal ability: no speech; limited vocalizations, or imitated words; having a small repertoire of spontaneous words, to use functionally; or communication effectively, with an alternative method (Hart & Banda, 2010). For all studies, thirty-six participants were included: seventeen were portrayed as having no speech; eleven were depicted as being able to produce vocalizations that weren’t words; four participants were categorized as small repertoire of words, to communicate; and four others were categorized as demonstrating functional communication, using alternative methods(i.e. Augmentative or Alternative Communication device). When studying effectiveness, PECS was a highly effective intervention, for nineteen of the thirty-five participants; moderately effective, for ten of thirty-five; minimally effective, for six of thirty-five; and showed no effect for one participant. In terms of increasing speech, five studies were targeted, as speech interventions. Therefore, ten participants were included: two proved that PECS was highly effective in increasing speech, two were moderately effective, two were minimally effective, and one student showed no effect. The effectiveness was measured by looking at word vocalizations, at home and school (Hart & Banda, 2010).

This study determined that an increase in vocalizations existed for six participants, although some increased at different rates, similar to the results found with Schwartz et al. (1998), and the “nontalker” group (Hart & Banda, 2010).

A meta-analysis by Tincani and Devis (2011) examined what effect PECS had on mands and vocalizations. One study within this analysis compared PECS, Responsive Education, and Prelinguistic Milieu Teaching for thirty-six preschool students with autism. This study concluded that both tactics increased spoken communication, but PECS provided a higher frequency of spoken communication (Yoder & Stone, 2006).

Comparatively, Hu and Lee (2019) studied vocal mands and aggressive behavior, along with PECS implementation. This study used the same measurement and analysis method of mands and vocalizations as Tincani and Devis (2011). Results are also similar in the two studies and determine that the PECS protocol increases vocal mands. The differences in the studies include the ages of the participants, and the number of participants in the study. Tincani and Devis (2011) examined 36 preschool students, while Hu and Lee (2019) studied the effects PECS had on one preschool student. The vast difference in number of the children in the studies still yielded the same outcome (Hu & Lee, 2019).

Car and Felce (2007) reported an upsurge in child to adult initiation for twenty-four participants who had PECS training through phase three, when placing them against kids that did not receive the PECS training.

After reviewing multiple single subject design cases, the authors found that PECS is an effective intervention to promote functional communication in individuals with autism and other disabilities, regardless of age, gender, diagnosis or setting (Car and Felce, 2007). According to this study, PECs training produced varying speech levels, with the limited number of participants. Ten participants out of sixteen improved in terms of speech, after using PECS (Car and Felce, 2007).

This meta-analysis, along with the previous by Tincani and Devis (2011), determined the increasing effect PECS has on communication—specifically, verbal communication. The two articles share common viewpoints of the dramatic increase PECS can have on communication. Hart and Banda (2010) determined nine out of ten participants showed an increase in speech, while Tincani and Devis (2011) determined ten participants, out of sixteen, showed an increase in speech. Both studies characterized speech in the same manner, mands and vocalizations, which makes the two comparable (Hart and Banda, 2011).

Similarly, Gordon et al. (2011) examined the effect PECS has on children who are nonverbal and diagnosed with autism. This study sought to determine the effect PECS had on speech, spontaneous communication, and social communication. In conclusion of this study, it was determined that PECS had an increasing effect on speech and communication, although the participants showed no increase for social purposes (Gordon et al., 2011).

The increase of utterance of words by children with autism was examined in a four-week study. The study included two components not typically found in the PECS protocol: only using ten icons, and repeating the word multiple times, trying to get the client to complete the vocal mand (Juhoh & Majid, 2017).  During typical PECS, vocalizations are, “encouraged but not required” (Bondy, 2001).

The first phase of the experiment, the experimenters used known cartoons, for the client to request items (Juhoh & Majid, 2017).  It was then transitioned to typical pictures.

Referenced as student A, the participant completed one utterance, within the first week of treatment, and concluded with five utterances, following week four. Student B completed two utterances within the first week of intervention, and increased to six, after four weeks of PECS training (Juhoh & Majid 2017).

The results found in Juhoh and Majid (2017) indicated an increase in word and speech after just two phases of PECS implementation, which directly coincides with research cited within Juhoh & Majid (2017):  Sulzer-Azaroff et al. (2009) confirms PECS to be a very effective learning technique in communication skills, and that it is also beneficial for individuals who have a speech delay (Juhoh & Majid, 2017).

The emergence of speech in children has been proven to exist when using PECS in play, and academic, settings (Charlop-Christy et al., 2013). This experiment sought to determine if speech, social-communicative and problem behaviors would increase, or decrease, with PECS intervention. Results determined that all three children completed the PECs protocol and increased in speech production and social-communicative behavior following the study, while problem behavior decreased (Charlop-Christy et al., 2013).

While PECS has proven to be effective for some clients in increasing mands, it has also been proven to increase untrained tacts, and intraverbals, for some participants (Ziomek & Rehfeldt, 2008). Ziomek and Rehfeldt (2008) examined mands similar to the previous articles, but also used untrained tacts and intraverbals, and along with how PECS affects those communication modalities, and when they would emerge. Results of this case suggest that PECS increased tacts, mands and intraverbals for participants with developmental disabilities, who previously had little to no limited communication skills (Ziomek & Rehfeldt, 2008).

Adapting PECS to Elicit Vocalizations

Greenburg, Tomanio & Charlop (2013) sought to determine two research topics: how PECS effected vocalizations in children with autism; and if children with limited verbal abilities can be taught to complete spontaneous vocalizations, along with the PECS protocol.

Topic one was introduced first, and data was taken on vocalizations. Before this study, all four participants were not able to request items, either with words or phrases (Greenburg et al., 2013). Three of the children used nonverbal communication (i.e. gestures, pointing or leading people by hand). One participant used vocal approximations, to convey requests. During the experiment, vocalizations were recorded, at free play times, while using PECS. Any vocalization attempt that wasn’t stereotypy, imitative or laughing was counted. The vocalizations did not have to be directly related to the item to be studied; the attempt of a vocalization is what was being considered (Greenburg et al., 2013).  However, the vocalizations must be in attempt to ask for an item, which was determined by the experimenter holding up the item. Data was also taken on the vocalizations attached to the PECS exchange. In this case, the participant asks for an item with PECS, and simultaneously, or within three seconds, makes vocalizations (Greenburg et al., 2013)

Within the first study, participant one had low levels of spontaneous vocalizations at baseline, but following the eighteen-month appointment, his spontaneous vocalizations increased to high levels–an average of fourteen vocalizations per session (Greenburg et al., 2013). Participant two completed an average of six vocalizations during baseline. This number decreased slightly, but quickly returned to an average of fifteen vocalizations per session. The third participant didn’t display any vocalizations during the free play baseline sessions. During his follow up, he increased vocalizations, to two per session. The fourth participant didn’t show any vocalizations throughout the whole study. In conclusion, this multiple baseline design experiment determined that three of the four participants vocalized at higher rates than during baseline (Greenburg et al., 2013).  From the results of this study, the experimenters made a conclusion–during PECS acquisition, a decrease of vocalizations may be observed, but it typically will follow the “u-pattern,” and increase directly after. This is because the clients are not relying on vocalizations, or approximations of words, and have a formal method of communication (Greenburg et al., 2013).

Study two within this article examined two children from the previous study, to determine if using PECS, by implementing time delay and verbal prompts, can increase spontaneous vocalizations (Greenburg et al., 2013). A multiple baseline designs across participants was used in this case. The delay phase was targeted first with both clients. During this phase, the therapist paused for 3 seconds after receiving the sentence strip from the participant. If the participant made any vocalization during this exchange, or within 3 seconds, the therapist read the sentence, “I want (item name),” and gave the client access. If the client did not make a vocalization during that time, the therapist still read the “I want (item name)” phrase, and gave the client access. This phase continued until the client paired vocalizations with PECS with 80% accuracy, across two consecutive sessions (Greenburg et al., 2013). However, it was discontinued if the client made less than 10% PECS requests, with spontaneous vocalizations, for three consecutive sessions (Greenburg et al., 2013).

The second teaching component was introduced–time delay, plus prompt–if the client did not make progress, using just the time delay procedure (Greenburg et al., 2013). The therapist paused for three seconds after the client exchanged the sentence strip, but then gave the client a full vocal prompt. If the client made a vocalization, they were given access to the item, for an average of thirty seconds. If the client did not make the vocalization, after the full prompt, the prompt was repeated, up to three times, to try for the vocalization. Following the third attempt, the sentence strip was put back on the book, and the item was put away; no access was granted (Greenburg et al., 2013).

After the participant paired the vocalization with the sentence strip, the verbal prompt was faded. Criterion for this phase was considered met if the participant completed a spontaneous vocalization independently, with 80% accuracy, for two consecutive trials (Greenburg et al., 2013) After this criterion was met, the participant returned to the phase used in study one (Greenburg et al., 2013).

Results of study two concluded that you can teach participants to pair vocalizations with PECS (Greenburg et al., 2013). Both participants did not pair vocalizations in the baseline phase, although one participant immediately paired it during the time delay phase, with 90%, or more, of the opportunities provided. Participant two began pairing vocalizations and PECS during the fifth delay, plus prompt, phase session. He reached mastery criterion for this phase on day nine. Following mastery, the participant was put into the time delay phase, without prompt; he proved generalization of this task by pairing the vocalizations with PECs, throughout this phase (Greenburg et al., 2013).

Time delay was another variable to the next study, by Cagilani et al. (2017). This experiment examines a similar aspect of adapting PECS, to increase vocalizations, and analyzes the effect time delay reinforcement and increasing response effort has, on the development of intelligible word vocalizations (Cagilani et al., 2017).  The participants of this study were four elementary-aged students, between the ages of five and seven, who were all diagnosed with significant developmental delay, or autism spectrum disorder. All participants had previously mastered PECS, through phase three-B. At baseline, participants were inconsistently echoing vocalizations and making unintelligible sounds, but not completing vocalizations, to communicate (Cagilani et al., 2017).

During this concurrent multiple probe design, across participants, vocalizations were either considered correct or incorrect, and had to be consistent with the item that was being asked (Cagilani et al., 2017). Experimenters used a vocalization screening tool to determine if the clients were able to use vocalizations for items, and decide what would be considered correct, and incorrect, per participant.  Two of the participants used approximations, and two used whole word mands (Cagilani et al., 2017).

The reinforcer delay condition within the experiment accessed immediate reinforcement for completing the verbal mand, and a slight delay for the PECS mand. This use of differential reinforcement was used in the previous study by Greenburg et al. (2013). The same delay method was used, although Cagilani et al. (2017) didn’t add a verbal prompt following teaching the delay.

When the participant completes the exchange, the communication partner waits to provide reinforcement, and if the client vocalizes during that time, they are given immediate access to the item they asked for (Cagilani et al., 2017). The delay started at one second and increased by one second for each day of treatment, until the client reached 80% accuracy for two sessions. The increase in time delay is a difference from the previous study. The time delay in the study by Greenburg et al. (2013) only included three to five seconds, without an increase. One participant was excluded from the increasing delay because he did not increase vocalizations over time (Cagilani et al., 2017).

The response effort experiment in this study involved moving the book .91 meters from the participant (Cagilani et al., 2017). In the PECS protocol, this is called distance and persistence; the participants have mastered this within PECS phase 2 (Bondy, 2001). Once the participant has vocalized for 80 percent of trials without using picture exchange, the book is moved .76 meters away from the client (Cagilani et al., 2017). After hitting the minimum of 80 percent vocalizations, the book is then returned to in front of the client, on the table. Moving the book back to the client was to determine if the client would continue to vocalize, or would revert to exchanging pictures (Cagilani et al., 2017).

The results of this experiment proved delay to reinforcement, with PECS, resulted in an increase in intelligible word vocalizations, with three participants. This experiment also proved that moving the PECS book away from the client decreased PECS exchanges, but the vocal requests remained consistent, with the delay part of the intervention (Cagilani et al., 2017).

The inclusion of time delay had an increasing impact on vocalizations in individuals with autism or developmental disabilities, for both previous studies (Greenburg et al., 2013) (Cagilani et al., 2017). The concept of requiring vocalizations throughout the PECS protocol may have been effective in this instance, but according to Bondy (2001), vocalizations should be, “encouraged but not required” (Bondy, 2001). This study conflicts with the author’s ideal implementation of PECS. According to Bondy (2001), differential reinforcement should be used, in this instance, to entice the participant to complete the vocalization. This implies that, if they complete the vocalization, they are given a bigger piece of the snack, or longer time with the toy asked for. The time delay is used, as previously discussed, when the client completes the exchange, and waits for the item. The communication partner should hold up the sentence strip, and wait three to five seconds before reading the strip. As you can tell by the procedure, a forced vocalization  never occurs (Bondy, 2001).

Naturally, the time delay, built within the PEC protocol in the fourth phase, has shown an increase in requesting, and speech development (Tincani et al., 2006). Two participants were taught PECS, with a delay, multiple baseline, line design. They both increased levels of requesting, after implementing PECS. However, one participant demonstrated a significant increase in speech development, primarily during the fourth phase of PECS. To examine this effect deeper, Tincani et al. (2006) used a reversal design, to study reinforcement and delay on vocalizations. Results included an increase in speech when reinforcement was provided, and a decrease when reinforcement was not provided, following vocalizations (Tincani et al., 2006).

Comparing PECs to Other Augmentative and Alternative Communication Methods

Comparing PECs to other augmentative communication methods was done in multiple cases to determine which method will increase speech and communication more rapidly and effectively. Adkins & Axelrod (2002) compared Picture Exchange Communication System (PECS) and American Sign Language (ASL). Four different types of sessions were implemented: training for PECS, training session for sign language, test for generalization of PECS and test for generalization for sign language. The number of trials to criterion was recorded along with the communication derived between both modalities. Results showed that PECS was more effective in all aspects for the subject with a developmental disability in this study (Adkins &Axelrod, 2002).

Similar to Adkins & Axelrod (2002), Chambers and Rehfeldt (2003) examined the use of PECS, and sign language. The end goal was to determine which method would increase mand skills to individuals with developmental disabilities in the severe range (Chambers & Rehfeldt, 2003). Four participants within this study were taught to mand for reinforcing items, using both communication methods (PECS and ASL).  Three of four participants acquired, and generalized, PECs usage, to ask for those items, while two of those three demonstrated mands for those items, using manual sign (Chambers & Rehfeldt, 2003). While the fourth participant was removed from the study because of an illness, they did increase in PECS usage and generalization, before being removed. The use of PECS was determined to be a more effective modality of requesting, when compared to ASL (Chambers & Rehfeldt, 2003).

Comparing sign language and Picture Exchange Communication System (PECS) confirmed that PECS increased vocal behavior, in Adkins and Axelrod (2002). Yoder and Stone (2006) compared PECS and Responsive Education and Prelinguistic Milieu Teaching, and the effect the two communication interventions have on spoken communication. Thirty-six preschoolers with autism were studied, and each treatment was trained to the participants, over a six-month time period. Three tests were done: pretreatment, post treatment, and a six-month follow up (Yoder & Stone, 2006).  Results indicated that PECS was more successful at increasing the frequency of spoken communication and number of words used, during the post- treatment measurement (Yoder & Stone, 2006).

When comparing different modalities of function communication, it is determined by this research that PECS is the most effective in increasing mand, words, spoken communication and vocalizations. This was also referenced within Cooper et al (2007), to examine the differences in sign language and PECS. However, within the article referenced, Tincani (2004) examined the effect on mands, using the two modalities. This study determined that PECS increased mands at a greater frequency initially then sign language did, when specifically examining mands, not vocal mands (Tinanci, 2004). However, after prompts for one client, sign language increased mands to greater frequency than PECS.  Although this study doesn’t show direct effect on vocal mands, it shows the need for studying the differences in each participant, individually (Cooper et al., 2007).

As referenced previously, sign language requires more accurate fine motor skills that may not be acquired, which can lead individuals to use PECS. (Chua & Poon, 2018). This is the motivation in studying the differences of effect on vocalizations and mands that sign language, and PECS, have.

No Significant Increase on Communication

The characteristics of participants that make them good candidates for PECS is an important aspect of using the protocol. A meta-analysis of eleven studies by Simpson (2011) contains children, under the age of eighteen, with autism, or developmental disorders. These participants completed a PECS study that sought to determine what aspects of a child would make them a good candidate for this intervention, along with the effect PECS has on communication.

The effect on speech within this study concluded that PECS did not have a massive increase to show a direct correlation for all participants. The researchers used the study to determine the characteristics necessary in children to gain the most from PECS: poor joint attention, strong object exploration, and limited motor imitation (Simpson, 2011).

The characteristics to gain the most from PECS determined within Simpson (2011) strikes a common limitation, discussed in studies by Hart & Banda (2010), Greenburg et al. (2013) and Cagilani et al. (2017). These studies relate to the common theory by Bondy (2001), that each person with autism is different, and the impact of PECS on them is determined by their characteristics. Characteristics that can help determine the success of a client, before implementing a program, can be a great help for potential PECS users (Simpson, 2011).

A meta-analysis by Flippin et al. (2010) found the effect of PECS on speech to not be increasing. This study includes eight single-subject case studies, along with three group studies, that examine the use of PECS and the effects it has on communicative behaviors, and speech or vocalizations. The outcomes specified in the literature reviewed includes exchanges, requests and initiations (Flippin et al., 2010).

Increases in communication were specifically observed within both single-subject and group designs, although generalization and maintenance were lacking in all single-subject designs, but one. The speech outcomes for the five studies, that included speech components, conclude that PECS does not increase speech for early learners with autism (Flippin et al., 2010). Five of the seventeen participants showed a slight increase in speech throughout the studies used, although, during one specific study, the speech was not maintained across a year time span. This study concludes that the increase of speech does not show a correlation with greater speech ability, after implementing the PECS protocol, and that it is a case-by-case analysis because all children are different (Flippin et al., 2010).

When looking at the measurement procedures of studies, many use frequency or rate, when measuring the usage of PECS, along with speech and communication. Howlin et al. (2007) used the assessment, Autism Diagnostic Observation Schedule-Generic (ADOS-G), among other methods, to measure communication and speech. According to Lord et al. (2000), this method of evaluation is a semi-structured standardized assessment that assesses communication, play and imaginative use of materials, for children with autism. It consists of four 30-minute modules, administered according to the participant’s expressive language (Lord et al., 2000).

The study by Howlin et al. (2007), found no correlation between the use of PECS and speech or communication. PECS protocol was implemented, with fidelity, and taught extensively to the teachers and parents, using training and observation. The 84 participants, with an average age of 6.8 years, were broken into three groups: immediate treatment (following baseline); delayed treatment (two terms following baseline); and no treatment. Frequency of vocalizations and communication were recorded during this experiment, along with the administration of ADOS-G, that concluded no increase in speech or communication, following PECS training (Howlin et al., 2007)

The results discussed in Howlin et al. (2007) were replicated, while measuring frequency, within a multiple baseline, alternating treatment study, by Boesch et al. (2013). Boesch et al., (2013) compared the use of Picture Exchange Communication System (PECS) and a speech generating device (SGD), and the effects they have on social-communicative behavior, and natural speech production.

Three participants, with autism and limited functional communication, were within this study. Results indicated little difference between PECS and SGD, and the effect they have on natural speech and social communicative behavior. Social communicative behavior seemed to have been encouraged in PECS phase 2 for the participants, and natural speech had no increase, with either method of communication (Boesch et al., 2013).

Generalization of PECS

As discussed, PECS has often been proven to generalize, across settings and communication partners (Greenburg et al., 2012).  Four children with autism were studied, specifically, for generalization, in the home setting, with parents; the community, with a stranger; and a new playroom, with a therapist; and prove that PECS could be generalized throughout those environments. Generalization can include simply asking for an item, using a PECS exchange, or in situations, such as Greenburg et al (2013), participants can be proven to generalize vocalizations, with the PECS exchange (Greenburg et al., 2013).

A multiple baseline design, across settings and participants, is adequate, to determine generalization. A study across environments determines if the behavior is used in each setting. Three students were used in a study, to determine if PECS generalizes to their home setting, and at school (Carre et al., 2009). This study showed generalization of PECS to the home and school setting, but it was highlighted that a functionally significant degree of generalization was not observed (Carre et al., 2009).

Generalization of vocalizations, play and social-communicative behaviors can also directly correlate with PECS use (Jurgens et al., 2009). Results of this study showed rapid acquisition for PECS phases one through three. Generalization of PECS exchanges were not observed in the generalization phase; however, the participant was able to generalize vocalizations- verbal mands, and initiation of communication (Jurgens et al., 2009). While generalization was not shown through this experiment, in terms of PECS exchange, it was shown in terms of other possible effects of PECS in the study (Jurgens et al., 2009).  Increases in spoken vocabulary, including length of intelligible spoken utterances, along with developmentally appropriate play, was observed (Jurgens et al., 2009).

A follow up of generalization is typically included in studies, to determine if the skills taught will generalize outside the study. Jurgens et al. (2019) followed up with their subject–three years, and seven months, after PECS training–to determine if the skill was generalized. During the follow-up, it was noted that PECS use decreased, while vocal mands increased. Conclusions were drawn that opportunities still need to be provided, in order to prove generalization of the task. However, with the child acquiring speech, the PECS book started to become less valuable to the participants (Jurgens et al., 2019).

Limitations of Current Research

Although conclusions are drawn, from many articles, about the effectiveness of Picture Exchange Communication System (PECS), there are still some gaps in literature, to prove a direct correlation. A common limitation discussed in studies by Bondy (2001), Travis & Geiger (2010), Schwartz et al. (1998) and Hart and Banda (2010), includes the effect natural maturation has on communication in children with developmental disabilities, including autism.

A child might have naturally started to communicate, and it might not be directly because of the implementation of PECS. Hart and Banda (2010) discuss the need for characteristics of participants to be studied. In order to determine the direct effects PECS has on communication, this study suggests that there is more need to understand each participant (i.e. cognitive level, age and disability that might affect gains in speech) (Hart & Banda, 2010).

Tincani (2004) discussed the need for knowledge of motor skills for each client, which can predict the outcome of PECS. This suggest that participants with better motor imitation skills can acquire other modalities, such as sign language, more quickly, which could be more effective in mands and communication (Tincani, 2004). The use of fine motor, within sign language, is previously highlighted in the study by Chua and Poon (2018), and how it may be easier to acquire, with greater fine motor skills.

Many studies, such as Cagilani et al. (2017), used PECS phases one through three, while only a few included phase four. When looking into the procedure aligned by Bondy (2001), phase four includes a suggestion for implementing the time delay, to try and encourage vocalizations. Travis and Geiger (2010) used PECS through phase four in their experiment, and proved an increase in utterances for participants. This is a limitation of some studies, and should be considered when looking at evidence and research (Travis & Geiger, 2010).  Bondy (2012) explains a limitation of most studies is not following the full protocol of PECS, and using all phases. He discusses that most studies with PECS stop during discrimination, phase 3, which is before encouragement, and reinforcement for vocalizations, start (Bondy, 2012).

The measuring tools used in each study do not align, to compare all studies, and the impact found on communication and speech by PECS. Hart and Banda (2010), along with Tincani and Devis (2011), discuss that, in some studies, approximations are used as vocalizations, but other studies don’t qualify approximations as vocalizations, and only accept whole words. Travis and Geiger (2010) used utterances to determine the effect PECs has on communication. They revealed an increase in those utterances, after following PECS procedures (Travis & Gieger, 2010).

Greenburg et al. (2013) assessed the effect of distance and persistence, and an increase in the response effort on increasing vocalizations, in participants with autism, or other developmental delays. They discussed that a limitation of their study that, if they made the PECS book not available in more of the study, the vocalizations could have increased more (Greenburg et al., 2013).

The procedures of PECS must be implemented, according to Bondy (2001); however, the meta-analysis, by Tincani and Devis (2011), outlined a variety of teaching and exposure to the PECS protocol, within each study used. This is a limitation of studies because the procedure must be implemented the same, across all experiments, in order to directly compare. Limited participants within the studies in this meta-analysis was also identified as a limitation, to prove a direct correlation, and the results of the studies (Tincani & Devis, 2011).

The outside environment for every study is something that should be accounted for. Limitations regarding this are discussed by Cagilani et al. (2017). Within this study, the researchers believe that communication and speech could have been affected differently, if the participants were allowed access to their books at home, and outside of the study. Cagilani et al. (2017) believe that the absence of the PECS communication book, outside the study environment, may have increased the value of reinforcement of PECS within the study. This would, in time, affect the use of communication (Cagilani et al., 2017).

Most studies examined PECS communication within a mealtime setting. For some clients, mealtime is aversive. Using mealtime can be easier for researchers because of the potential amount of requests; however, it doesn’t expand, and include all components of the clients’ repertoire (Cagilani et al., 2017).

Future Recommendations

Future directions for this topic should be drawn from the limitations, and lack of study, in areas concerning PECS and communication. Tincani and Devis (2011) discuss the need for future studies to examine all conditions and characteristics of participants. This includes other environments, items requested, and characteristics of the participants. Tincani and Devis (2011) also explained the need for more research on characteristics that will predict the acquisition of speech in people with autism, and if the emergence of approximations could lead to full words.

More research should be conducted following the full PECS protocol, to determine the effect it has on communication. Tincani and Devis (2011) suggest that going farther into the PECS protocol could increase the impact it has, on communication and speech.

Cagilani et al (2017) used response effort and shaping to elicit vocalizations in participants, but did not discuss the changes in word production and approximations, throughout the study. The study had criteria for approximations, and when they were considered, but never took data on the changes and progress that was made, within those approximations and words. The idea of changes in vocalizations should be an area of further study, to determine if individuals can make progress in the approximations, or sounds, of words, as well as completing full words and utterances.

The length of some studies that were conducted was very limited. Khuansuwan and Kummuang (2014) only studied speech and communication over a year time span. A suggestion made by the authors, to grasp the full picture and effect of PECS, was to lengthen the study.  Conklin and Mayer (2011) intended to complete the full protocol with their participants, but only got one client through phase 4. They highlight the differences in acquisition rate of participants with their study and included it as a limitation (Conklin & Mayer, 2011).

Ethical Considerations

While designing interventions for individuals with autism, or other developmental disabilities, within applied behavior analysis, the Professional and Ethics Compliance Code for Behavior analysts (PECC) must be referenced (Behavior Analyst Certification Board, 2014).

One common limitation of studies was the characteristics of clients and doing more research on what characteristics would help to be successful with PECS. Characteristics of the individuals is a key component to treating individuals with limited functional communication abilities. This aligns with the PECC code 1.01, that explains the need to evaluate the background information, and be aware before implementing a plan. This also means information about the client that could help with the intervention (Behavior Analyst Certification Board, 2014).

When comparing Picture Exchange Communication System to vocal behavior, it is essential to exhibit scientific knowledge within the field. Section 1.01 of the PECC explains the use of relying on information that is based on science, and behavior analysis, when making decisions in human assistance, or changing behavior (Behavior Analyst Certification Board, 2014). Using evidence-based strategies is vital when changing behavior, especially vocal behavior because that is a method of communication for many people (Behavior Analyst Certification Board, 2014). This is why so much research has to be done on topics, to determine it is effective, before using it on a client.

Boundaries of competence is the next code that essential in changing verbal behavior and implementing Picture Exchange Communication System (PECS). The boundaries of behavior analysts should include providing services, and teaching, within the limits of their skill and education. This was upheld within the studies highlighted. The researchers used a team of people, when implementing a plan, that included a speech pathologist and teachers, or implementers, that were properly trained on how to implement the functional communication skill of PECS (Behavior Analyst Certification Board, 2014).

Ethics code 2.03 discusses the use of appropriate consent. The client, and their caregiver, should always be aware of every aspect of the experiment and interventions that are put in place. The rights and privileges of the clients are crucial and correlate with consent, which is highlighted in section 2.05 of the PECC (Behavior Analyst Certification Board, 2014). Behavior analytic assessment consent is outlined in section 3.03, and explained as consent to every procedure, and the need for written approval (Behavior Analyst Certification Board, 2014). The need for consent is discussed throughout articles but is often overlooked in practice. Before using any piece of a behavior plan, it should have the written approval of all parties involved. (Behavior Analyst Certification Board, 2014).

To avoid false or deceptive statements, both sides (PECS increasing communication, and PECS having no effect on communication) were researched, and included, in this review. In compliance with the PECC sections 8.01, behavior analysts do not make untrue or deceptive statements. This code identifies that behavior analysts do not implement tactics and programs that are non-behavior analytic in nature (Behavior Analyst Certification Board, 2014). It would be unethical to only include some research about the effect PECS has on communication, and not include the other analyses.

When referring to other articles or someone else’s work, behavior analysts must give credit to that researcher or behavior analyst (Behavior Analyst Certification Board, 2014). This is outlined in section 8.02, and states that behavior analysts must obtain permission to use materials, and must provide citations that are the property or findings of someone else (Behavior Analyst Certification Board, 2014). Many articles, that have been reviewed for this research, included other research, to support their hypothesis before providing the results from the study. Throughout this analysis, proper citations and references were used to give credit to researchers who completed the studies, which is in compliance with the PECC.

Last, behavior analysts should adhere to the guidelines for research, outlined by the PECC. Behavior analysts should not make up false research, or fabricate research. They should not omit findings that might alter versions of the research (Behavior Analyst Certification Board, 2014). Behavior analysts should not publish data, when it has been previously published, without proper recognition. After research is complete and published, they do not withhold data for other professionals to use, to further research (Behavior Analyst Certification Board, 2014). As mentioned above, others’ research is commonly used to support hypothesis, and determine the most ethical treatment or intervention.

Conclusion

Conclusions drawn from research determine that speech and communication could possibly be impacted, and increased, by implementing Picture Exchange Communication System (PECS). There is evidence to suggest both sides of the argument: PECS does increase vocalizations, and PECS does not increase vocalizations. The studies highlighted used different measurements of vocalizations, from mands, tacts, words, utterances, and intraverbals, along with different participants, ranging from preschool-age, to adults.  In order to determine a direct correlation, between PECS and vocalizations, more research is needed—specifically, on the participants and the full protocol of PECS.  Preliminary conclusions can be drawn that completing the full PECS protocol can greatly impact the chances that vocalizations will increase, according to research done, and articles highlighted in this analysis.