6 Reasons to STOP Assigning a Mental Age to Disabled Students

Mental Age

I guess it’s a coping mechanism. Or a way of trying to parent and better understand our kids. But it’s also an antiquated practice that needs to go. I’m talking about assigning a mental age to our kids. In particular, this happens with students who are intellectually disabled or autistic, or both.

You know what I’m talking about. The “Oh, he has the mental capacity of a 3-year-old.” Even typing those words out makes me cringe and wince. Before you X out of this post and curse me for being all judgy, please reconsider.

mental age

Before you mutter “judgy b!tch” and X out of this post, I ask you to please pause. Because perpetuating this practice is harming our kids. It’s not always easy or comfortable to examine our own personal biases, I get that.

We want our kids to thrive and be accepted and having meaningful contribution to their community. Mental age is a roadblock to that.

What is Mental Age? Definition

While intelligence in humans has been observed for thousands of years, the concept of mental age has been around since the early 1900s. It was Alfred Binet who developed and formalized the practice of intelligence testing.

Binet developed questions that focused on skill sets not explicitly taught in schools, such as attention, memory, and problem-solving skills. He was helping the French government determine which school students would need extra assistance.

He realized that some younger children were able to exhibit skills that some older children were not able to answer, and vice versa. Based on these observations, Binet developed the concept of mental age, or a measure of intelligence based on the average abilities of children of a certain age group.

In other words, if a person could perform a majority of the skills that most 2-year-olds could perform, they were assigned a mental age of 2. It didn’t matter if they were 1, 2 or 22–their mental age was 2.

Today it has evolved in both thought and practice. Perhaps your child has done either the VBMapp evaluation or a Vineland Assessment. Many of the assessments that our kids lump various skill sets together based upon what a majority of an age group can do.

Assigning a Mental Age

Using today’s evaluations, I find that most students are assigned a mental age based upon the skill sets they have mastered. For decades, doctors and other clinicians routinely used mental age references when communicating news to parents. Even sometimes saying things like they will “mentally be like a child their whole life.”

Let’s use the Vineland as an example. The Vineland evaluates children in various “domains” including communication, daily living and more. If a child can perform the skills that most 3-year-olds or 4-year-olds can perform, you may hear clinicians or teachers say “he has the mental capacity of a 3-year-old.”

So what’s the problem? Well, what if the student assessed is 12? Or 16?

Many parents accept this as standard practice. After all, if we can picture what a neurotypical 3 or 4-year-old can do, it gives us frame of reference. Right?

No. Here’s the harm.

Mental Age and the Eugenics Movement

Most people are aware of the history of the Nazis, and their selective breeding/reproduction. Most people are horrified by it, as they should be.

However, what many American parents don’t know or don’t acknowledge, is that the eugenics movement was alive and well here in the USA too. And other “good” countries, or allies. It wasn’t just the German Nazis who practiced this.

Laws and policies inspired by eugenic principles were used here in the USA well into the 1940s and there are still remnants of them here. The quick definition of eugenics is “selective breeding.” But, there were laws and policies in place to reinforce this ideology. Mental Age Categories were a large part of this.

“Mental age theory” was a major feature of the eugenics movement in the USA. It is also the foundation of modern-day labels like “high functioning” and “low functioning.”

“Difficulty doing specific tasks isn’t the same thing as being an actual child. … I am not mentally 12. I am mentally 28. I just have an intellectual disability.”

Ivanova Smith, adult with an intellectual disability

What we refer to as ‘intellectual disability’ was called ‘feeblemindedness’ in the early 1900s. Feeblemindedness was separated into 3 categories.

  • Moron: someone with the mental age of a 9-12 years old
  • Imbecile: someone with the mental age of a 6-8 year old
  • Idiot: someone with the mental age or a 2-5 year old

A 1927 Supreme Court Case, Buck v. Bell, legalized forced sterilization of disabled adults.

In writing the decision, Chief Justice Oliver Wendell Holmes opined, “three generations of imbeciles is enough.” He also wrote, “It is better for all the world, if instead of waiting to execute degenerate offspring for crime, or to let them starve for their imbecility, society can prevent those who are manifestly unfit from continuing their kind.”

While most of these laws are no longer enforced, newer laws and court cases overturning them did not come until the 1960s and some as recent as 1988. This is not ancient history–which is why it is so important that we be proper allies to the disability community in this effort.

Why Mental Age Must Stop

  • Mental age determination has a disturbing history. Using mental age as a reference point is not a practice that helps the disabled person in any way, and only perpetuates stereotypes. It might help the evaluator, teacher or parent better visualize and understand the skill sets of a child, but it does absolutely nothing helpful for the child. It is for the ableds reference point, not the disabled person’s.
  • Mental age is treated like a ceiling, a maximum ability. Once a person is assigned a mental age, they are rarely expected to exceed that age or grow.
  • Mental age is limiting. Some students may be highly skilled or knowledgeable in some areas, but experience impairments or skill deficits in other areas. Tests that measure a few kinds of intelligence can miss other kinds of intelligence or compensatory skills that the person uses.
  • Mental age reinforces and perpetuates infantilization of disabled students. This is something I experience on a daily basis with my son. People talk down to him, or in a sing-songy baby voice. They treat him like a toddler, as happens with many disabled adults. Assigning a mental age that is below the person’s chronological age only reinforces this type of discrimination.
  • Mental age is used to oppress disabled people. It would be awesome if we used mental age as an opportunity for growth. “He’s mentally a 5-year-old, but we’re working on getting him to 20!” Nope, never works like that. Instead, it’s “He can’t get a job/drive a car/live on his own, he’s only mentally 5.” Mental age has forever been used to forcibly sterilize disabled individuals, force them to live in institutions and prisons and deny them meaningful participation in society.
  • Not being able to do a task is not a sign of maturity. If a child cannot complete a task, they cannot complete a task. You either teach the skill, or accommodate for the lack of skill, or ideally, both. But why are we lumping together areas of need and age/maturity? It’s illogical.

Overcoming Mental Age Discrimination

First of all, just stop doing it. Just stop. Do not allow yourself to say the words, or even think them. Force yourself to think of something else to say, and chances are, the correct words will follow.

Focus on skill sets. My son has poor motor planning and is a very slow processor. He lacks some skills, not because he has a ‘mental age of X’ but because his processing is slow and his motor planning is poor.

“You can support people without condescending to them. … Yes, I’m an adult. That doesn’t mean that I don’t have support needs. Rather, it means I should be able to share what my support needs are and direct the means by which I receive support.” 

Finn Gardiner, adult with a developmental disability

Several years ago, I had a client whose mother was interviewed for an article in the Philadelphia Inquirer. In the article, there is a quote from Mom, stating that her son “had a mental capacity” of a 3-year-old. I don’t know what else she said, as she did the interview against my guidance and suggestions (for this very reason).

But what the article didn’t say–that the young man had a part time job at which he was successful. And that he was completing a vo-tech program. That he could ride a city bus pretty much all over the city and get to where he needed to go. I don’t know any 3-year-olds who can do this.

But any friends, family, current employers, future employers….anyone from now on, who Googles his name, will see the article and the reference to his mental age.

Tell me how this is helpful?


Also read: Age Appropriate Activities–Who gets to Decide?