Against "mental age"

Why do so many judgments from the Court of Protection use ‘mental age’ to describe people with learning disabilities?  I’ve lost count of the number of judgments where this is used.  Presumably it’s occurring because at some point an expert psychologist or psychiatrist has used the term in a report, but I really wish they wouldn’t.

I remember learning about ‘mental age’ when I was an undergraduate studying psychology.  It’s a concept derived from certain kinds of psychometric tests.  In the early twentieth century two psychologists – Alfred Binet and Theodore Simon – developed tests of children’s verbal abilities to identify ‘mental retardation’, often for the purpose of diverting these children away from mainstream education.  It’s origins were in creating a ‘scientific’ measure to justify exclusion from mainstream society.

Simon and Binet calculated mental age by working out the ‘normal’ performance of children of different ages on various tests they had devised; a child’s ‘mental age’ was determined by which age group their performance on these tests most closely resembled. Simon and Binet’s tests were an early form of Intelligence Quotient (IQ) testing, and a person’s ‘mental age’ in fact has an arithmetically equivalent IQ score.  If a child’s mental age’ is the same as their chronological age, then their IQ score is 100 – the average score.  Because ‘mental age’ is calculated from IQ scores, the concept attracts all the criticisms of IQ testing in general.

Later on when I was an assistant psychologist working in neuropsychology I would be asked to administer psychometric tests, including IQ tests.  I used to hate doing this, reducing a person to a set of scores; it’s one of the reasons I left working in psychology.  The tests we used asked some questions which were clearly culture-bound (I remember asking one young woman if she knew who Cleopatra was, she replied that they were an R&B girl group known for the hit song Comin’ Atcha! – which is, strictly speaking, correct, but scored no points on the test).  Working in neuropsychology, I administered these tests to people with a wide range of possible conditions – from brain injuries, possible dementias, mental health problems.  I was only asked to calculate ‘mental age’ for a person with a learning disability.

I hate ‘mental age’.  It’s arithmetically redundant – we don’t need to use it – but we do.  The British Psychological Society (BPS) issued guidance in 2000 which says:



Look at how readily analogies with children were used to justify the judgment that the meaning of liberty was different for ‘people like that’ in Cheshire West: ‘one could just as well argue that a small child, because he has to live where his parents determine, is deprived of his liberty if, as a baby, he is strapped into a buggy or, as an older child, is strapped into a car seat’.  The judgment meant that people with intellectual and cognitive disabilities could be subject to far higher levels of restrictions than people without those disabilities before they were entitled to legal safeguards against arbitrary detention.  Lawyers and philosophers defending the judgment in a seminar at One Crown Office Row readily slipped into analogies with children.  As the Official Solicitor retorted from the audience: ‘one can be flippant about little children if one wants, but these aren’t children, they’re adults.’

Here is what Katherine Quarmby had to say about the use of ‘mental age’ metrics in her seminal report on disability hate crime for Scope:

This problem of language extends beyond vulnerability. The term ‘bullying’, is often used, with the best of intentions, by organisations working with people with learning difficulties to help them understand that they are being wrongly targeted and to seek redress. This is then reflected in media reporting, where reporters will often describe people with learning difficulties as “having the mental age of a child”.  Such language encourages the infantilisation of disabled victims of crime within the criminal justice system and masks the gravity of their experiences. It can lead to front-line police officers, faced with a victim saying that they are being ‘bullied’, failing to take a crime seriously and then record or investigate it appropriately.

Infantilising people with learning disabilities can lead to the normalisation of criminal offences against them which would be taken seriously for other members of the population.

And if ‘mental age’ diminishes the importance of liberty and personal security for people with learning disabilities, it’s just downright creepy in the context of decisions about sex and capacity.  As Jonathan Herring wrote in his essay for the Feminist Judgments Project, presenting E in Sheffield City Council v E (2004) as functioning at the mental age of a thirteen year old ‘automatically creates suggestions of paedophilia’ and ‘involves infantilising E and reducing the weight that is attached to her views, and it affects the assessment of her capacity’.

Do these ‘mental age’ metrics impact upon the assessment of capacity?  This is what Hedley J said about mental age in LB Haringey v FG:

It is of course not open to a court to say that because someone functions at a chronological age of seven, and because no one would dream of ascribing capacity to a seven-year-old, therefore you do not ascribe capacity to the person in question; it is a more subtle process than that. However by the same token it is essential to retain that piece of information as an important guide in the assessment of capacity.

It would be wrong to caricature the Court as straightforwardly treating a person as if they were a child on the basis of mental age, but it certainly seems to occupy some place in the imagination.

There is a lot more to being older than improving one’s IQ scores.  One accumulates life experiences, responsibilities, desires and outlooks which are influenced by a range of developmental, social and generational factors.  If you are determined to use impoverished IQ metrics to describe a person’s ‘intellectual functioning’, then use IQ – at least that conveys what is actually being tested: a person’s ability to solve a few puzzles and know who wrote Hamlet.  There is no need whatsoever to use ‘mental age’ to describe the functioning of adults in psychometric tests; if you are doing so, ask yourself why?  Why do you want to feed a perception that the adults you are working with are children, and does this influence how you and others value their legal capacity, liberty, sexuality and their other legal rights?


3 thoughts on “Against "mental age"

  1. Pingback: An epic shitshow: disability, communication, and Anna Stubblefield | Feminist Philosophers

  2. Pingback: Autistic Culture for Beginners | End Autism Stigma

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