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PECS (Picture Exchange Communication System)

PECS is a frequently used intervention for autistic children developed in the 1980s. PECS involves exchanging pictures for items / food / activities whereby a user (the child) and the physical prompter (adult) is required. PECS is intended to develop functional and intentional communication. Bondy & Frost are the creators of PECS, who designed 6 phases:

Boardmaker symbol of a person smiling, one hand pointing at themselves. Writing above: "I want"

How to communicate - exchanging pictures for things the child wants

Distance and persistence - children are taught to 'be more persistent communicators'

Picture discrimination - selecting from 2 or more pictures

Sentence structure - "I want X"

Responsive requesting - children are asked "what do you want?"

Commenting - children are taught to comment in response to certain questions

So what's wrong with PECS?

It's based on ABA, which the autistic community are vehemently against (see further down for ABA section) 

It uses physical prompting. 
PECS uses 'hand-over-hand in Phase 1 whereby an adult withholds an item (food or toy) from the child. Hand-over-hand is a restrictive practice as it violates a person's body autonomy. In Phase 1 another adult acts as a physical prompter by typically sitting behind / next to the child and reaching for the their hand, wrist, or arm to stop them from taking the item they want UNLESS they pick up the symbol / picture first and hand this to the adult. If they do this, they then get rewarded with the item. Not only is this method unethical and harmful, it is an incredibly unnatural way of developing communication. This is how you train dogs and is literally based on the same behavioural principles of dog training. Touching a child's body without their explicit consent teaches the child that they don't have a say in whether someone can touch their body or not and makes them  vulnerable to physical or sexual abuse - this is well documented.


It causes the child distress and frustration
By withholding an item, activity, or food until the child presents the 'correct' behaviour leads to frustration and distress. In addition, the child has to go and find the relevant picture and hand it to the adult, which takes time and leads to increasing levels of frustration and dysregulation, resulting in meltdowns. It's reported that pictures can often go missing which can cause even more frustration for the child because they can't communicate their wants and needs.

Communication function is limited

The main goal of PECS is to teach requesting. This is is only one aspect of communication and excludes expressive communication skills that are required for children to engage in social interaction and to make friends. Most communicative attempts are not about requesting.

The evidence base is limited
In a 2010 meta-analysis (Flippin et al.,) 11 studies were evaluated in order to assess the effectiveness of PECS in helping autistic children. The evidence claiming that PECS leads to spoken language is weak due to the quality of the research, and includes a report written by the creators of PECS - extremely biased. The research is also limited in regards to generalisation (children using those learnt skills in a range of new / different settings). In addition, the majority of evidence features small sample sizes and assessors not being blinded.

It does not align with Neurodivergent-affirming practice and doesn't uphold the views of the autistic community -
The easiest way to know whether an intervention for autistic children is in-line with a pro-neurodiversity model is to look at the language used in the company's website, manuals, and literature. Their website uses person-first language ("individuals with autism") which the autistic community have been extremely vocal about being preferred to be called "autistic person", openly states that they incorporate ABA practices) which again, is opposed to by the community, and there is no co-production or consultation with autistic people. It is entirely led by 'consultant' neurotypicals which is a fundamental problem:


ABA (Applied Behaviour Analysis)

What's the controversy?


The language of ABA

Antecedent: what happens before a behaviour

Consequence: what happens after a behaviour ('good' or 'bad')
Deprivation: the more 'deprived' or a particular reinforcer (item, food, activity), the more the child will wants it
Discrete Trial Training (DDT): a teaching method whereby a task is taught in multiple repetitions 
Extinction: reducing or eliminating a behaviour through withholding 

Intensive Behavioural Intervention (IBI): high intensity ABA 20-40 hours per week

Operant conditioning: learning that uses rewards and punishments for behaviour

Prompt: assistance given to the child to complete a task e.g. physical, gestural, position, verbal, visual

Physical Prompting: touching a person's body part to produce a desired response. E.g. hand-over-hand, grabbing their wrist

Punishment: a consequence that happens after a behaviour (positive or negative)

Reinforcer: an item, task, food that motivates the child to complete a task or engage in a behaviour

Reinforcement: anything that increases the likelihood of a behaviour happening again in the future

Shaping: teaching a behaviour by reinforcing desired behaviours - rewarding a child for doing something close 

Target behaviour: the behaviour that is being increased or decreased.

A man and a dog on grass with what appears to be dog training: dog's paw held up to the man

ABA is frequently used in the USA and is as a primary intervention for autistic children. Most autistic people view ABA as the equivalent of dog training because it uses the same principles, mechanisms and techniques [2]

"you have a person in the physical sense, but they are not people in the psychological sense"
- Ivar Lovaas describing autistic children


In the 1970s, Psychologist Ivar Lovaas (the father of ABA) and also a pioneer in gay conversion therapy, intended to make autistic children as "normal" as possible by extinguishing non-desired behaviours. In 1987 Lovaas published a study [3] where autistic children received up to 40 hours of therapy sat at a table, with a "heavy emphasis on teaching eye contact". 47% of the children went on to "lose" their autism diagnosis and were described as "indistinguishable from their typical peers" e.g. making friends, passing education without assistance. The "Lovaas Method" became well known. He discouraged stimming, shouted at children, and even gave electric shocks to children to stop certain behaviours


1. Behaviors are affected by their environment.

2. Behaviors can be strengthened or weakened by its consequences.

3. Behavior changes are more effective with positive instead of negative consequences.

4. Behaviors need to be reinforced or disciplined for socially significant changes.


  • "Treatment for autism"

  • "Most effective when used 30-40 hours per week"

  • "if the child has tantrums to get their needs met"

  • "teach the child replacement behaviours"

  • "seeks to develop socially acceptable alternatives for aberrant behaviors"

A woman is holding up two cards in her left hand. Each card has an image of an animal. A child is sat opposite facing the woman with a table inbetween them both.


  • Decrease 'inappropriate' behaviours

  • Reduce 'undesirable' behaviours

  • Reinforce 'appropriate' behaviours through rewards

  • To change behaviours

From the ABA literature / guidelines

The contradictions in their codes of practice [4]:

  • "Behavior analysts are truthful and honest and arrange the environment to promote truthful and honest behavior in others" and "do not knowingly engage in behavior that is harassing or demeaning to persons" (therapists are in denial about their practice and deliberately change the child, not the environment. Many of their techniques are harmful and manipulative)

  • "In their work-related activities, behavior analysts do not engage in discrimination against individuals or groups based on age, gender, race, culture, ethnicity, national origin, religion, sexual orientation, disability, language" (ABA specifically targets a disabled, marginalised group of people for the sole purpose of changing their undesirable behaviours. This is discrimination toward individuals and groups.)

  • "Behavior analysts always have the obligation to advocate for and educate the client about scientifically supported, most-effective treatment procedures" (the evidence is highly questionable - see further down)

  • " and "behavior analysts uphold and advance the values, ethics, and principles of the profession of behavior analysis" (ABA techniques deny children's consent and do not listen to what the child wants or needs. The child doesn't get a say. It does not uphold the ethics that they claim. It uses physical interventions and physical prompting which violates consent and needs "The type of assessment used is determined by client’s

  • "If a client’s legal rights are being violated, or if there is the potential for harm, behavior analysts must take the necessary action to protect the client" (the client's rights are frequently violated)

  • "Behavior analysts ensure that aversive procedures are accompanied by an increased level of training, supervision, and oversight" (Despite ABA 'changing' over the years and claiming to recommend reinforcement rather than punishment, their codes of ethics are clearly stating here that it's OK to carry out harmful techniques


Whilst there has been a shift in ABA practices, there are still overtly abusive practices that still go on. Whether 'old ABA' is still going on, as an intervention, ABA still:

  • aims to reduce, eliminate and punish 'undesirable' behaviour

  • teach 'desirable' behaviour

  • focuses on changing behaviours that neurotypicals deem as unacceptable

  • follows an outdated, ableist Medical Model of disability

  • uses the same behaviour modification techniques as dog training​, 

  • rewards 'good' behaviour which forces children to perform

  • violates a child's body autonomy

  • is compliance based

  • encourages masking

  • is recommended between 15-40 hours a week

  • uses stigmatising, negative language e.g. problem behaviour, replacing behaviours

  • does not uphold the views of the autistic community

Woman sat at a table facing a child, holding a picture up to show the child

To summarise: why I won't use ABA

It damages self-esteem and dehumanises autistic children
Even if the parent/professional is well-intentioned and believes ABA is helping the child, it's sending lots of unspoken messages to the child that they need fixing and are broken (the Medical Model of disability). It sets up a lifetime of mental health problems and shame around being autistic.

Aside from the ethics, ABA techniques lack effectiveness and generalisation
"Training individuals with ASD to acquire new information by repeating the information actually harms their ability to apply that learned knowledge to other situations" and "individuals with autism need to be taught in ways that support generalisation rather in ways that reinforce over specificity" [5]

ABA addresses 'symptoms' of autism, encourages masking, worsens mental health
It is well documented that using ABA to stop / reduce behaviours in autism leads to devastating outcomes. By simply eliminating behaviours leads to masking and without addressing the child's underlying distress & unmet needs contributing to that behaviour, results in greater mental health problems down the line because it simply suppresses the behaviour - which will inevitably come out as crises and meltdowns. The child's distress is still there bubbling under the surface but they've now been conditioned to suppress this behaviour - just to keep other people happy and make their lives easier. This leads to mental, physical, emotional exhaustion and shame. It ignores the child's wants and needs and increases potential underlying sensory distress. By the time the child reaches adulthood they will have experienced a lifetime of repeated trauma and gaslighting.

It's compliance driven
I won't base my therapeutic input on the child having to be compliant with me. Autistic people have had a lifetime of being conditioned to be compliant and please others. In fact, one of my goals for my students is to reduce their compliance-seeking with adults - and to me. I ensure I am communicating and interacting with them in a way that encourages them to be autonomous, independent, and to say "no". I create opportunities for them to refuse, express different opinions, and communicate their needs even if it doesn't come out as polite.


I reassure and encourage them to consider their own perspective and not immediately jump to how others may think / feel. I validate their experiences first. I model my own difficulties and say how I manage them. I acknowledge my mistakes if they bring something to my attention something I've done/said which have hurt / upset them. I apologise for not explaining something clearly. I apologise for getting something wrong and provide them with positive experiences when they advocate for themselves. 

It uses aversive, punitive techniques

ABA emphasises 'desirable' behaviours whilst punishing undesirable ones. "compliance, learned helplessness, food/reward obsessed...magnified vulnerabilities to sexual and physical abuse, low self esteem, decreased intrinsic motivation, robbed confidence, inhibited interpersonal skills, isolation, anxiety, suppressed autonomy, prompt dependency, adult reliance etc" [6]

ABA uses rewards and praise (like dog training)

Praise and rewards are often well-intentioned but can massively backfire, especially with autistic children. It reinforces compliance-seeking. This is well-documented. Instead of trying to develop a child's motivation through superficial methods, we should be developing the child's 'intrinsic motivation' (the child does something without obvious external rewards and instead does something out of inherent enjoyment, curiosity, and satisfaction). "Good job!", "good boy!", "you've been a really good girl today".... Contrary to the popular myth, reward systems can actually result in children performing 'poorly' and condition them to seek approval.

ABA is recommended to be delivered at a high dosage e.g. between 15-40 hours weekly

Any intervention that requires this amount of dosage I believe to be unethical. Especially for young children (below age 5). For a child who is autistic this places extraordinary demands on them given that they are already living with extraordinary sensory / emotional / physical / cognitive demands on a daily basis. 

Autistic children & adults have been traumatised by ABA

ABA has caused children PTSD.  Evidence of ABA increasing PTSD symptoms in autistics: [7]  "We will argue that employing ABA violates the principles of infringes on the autonomy of children" [8]

A child appears to be crying and distressed. He is leaning on a couch or bed with an adult's hand holding onto his hand and wrist.

Just because it's 'evidence-based' doesn't mean it is ethical.
There are numerous claims that ABA gets results. It stops 'challenging' behaviours and on the outside the child may appear happier and more cooperative. The families may be able to do things that they once they couldn't have done (go shopping without the child having a meltdown). Positive behaviours increase = the intervention must be working, right? .........But at what cost? Just because something gets results doesn't mean it's ethical. All that could have happened is the that the child has simply been conditioned to mentally / physically / emotionally suppress their distress. 

The evidence-base isn't actually that good. It's questionable (yet claims to be outstanding)

"An overall low quality body of evidence mainly from poor quality studies suggests Intensive Behaviour Intervention (ABA) improves intelligence or cognitive skills, visual-spatial skills, language skills, and adaptive behavior compared with baseline levels of other treatments". "The strength of the evidence in this review is limited because it mostly comes from small studies that are not of the optimum design. Due to the inclusion of non-randomised studies, there is a high risk of bias and we rated the overall quality of evidence as low / very low." [9]


We must listen to what the community are telling us especially since their voices have historically been ignored. Regardless of whether we as professionals agree with the principles of an intervention, we must uphold the views of the autistic community. The community has been extremely vocal about ABA and the harm it's caused (and continues to cause). 




[3] Lovaas, O. I. (1987). Behavioral treatment and normal educational and intellectual functioning in young autistic children. Journal of Consulting and Clinical Psychology, 55(1), 3–9.

[4] BACB Professional and Ethical Compliance Code for Behavior Analysts -

[5] Harris H, Israeli D, Minshew N, Bonneh Y, Heeger DJ, Behrmann M, Sagi D. Perceptual learning in autism: over-specificity and possible remedies. Nat Neurosci. 2015 Nov;18(11):1574-6. doi: 10.1038/nn.4129. Epub 2015 Oct 5. PMID: 26436903.

[6] Aileen Herlinda Sandoval-Norton & Gary Shkedy | Jacqueline Ann Rushby (Reviewing editor) (2019) How much compliance is too much compliance: Is long-term ABA therapy abuse?, Cogent Psychology, 6:1, DOI: 10.1080/23311908.2019.1641258

[7] Kupferstein, H. (2018), "Evidence of increased PTSD symptoms in autistics exposed to applied behavior analysis", Advances in Autism, Vol. 4 No. 1, pp. 19-29.

[8] Wilkenfeld DA, McCarthy AM. Ethical Concerns with Applied Behavior Analysis for Autism Spectrum "Disorder". Kennedy Inst Ethics J. 2020;30(1):31-69. doi: 10.1353/ken.2020.0000. PMID: 32336692.

[9] Reichow B, Hume K, Barton EE, Boyd BA. Early intensive behavioral intervention (EIBI) for young children with autism spectrum disorders (ASD). Cochrane Database Syst Rev. 2018 May 9;5(5):CD009260. doi: 10.1002/14651858.CD009260.pub3.

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