Even before her son started kindergarten, Ashley Meier Barlow realized that she might have to fight for his education. Her son has Down Syndrome; when he was in prekindergarten, school officials in Fort Thomas, Kentucky, told Barlow that he wouldn’t be going to the neighborhood school, with some special education accommodations, as she had assumed.

Instead, the educators told Barlow that they wanted her son to attend a classroom across town meant for children who are profoundly impacted by their disabilities. Barlow immediately resisted, because she knew the curriculum would likely focus on life skills, and her son might never be taught much reading beyond learning the shape of common, functional words like stop and exit. “I think about it 10 years later and it still makes me want to cry,” said Barlow. “They had no confidence that they would be able to teach him.”

Driving the recommendation, Barlow knew, was her son’s low cognitive scores. “If [schools] have an IQ that suggests a child’s cognitive ability is significantly less than average, they will rely on it every time,” said Barlow, who now handles special education cases in her work as an attorney. To get her son even modified access to the regular kindergarten curriculum, Barlow would need to show that his potential to learn exceeded his test scores.

For generations, intelligence tests have played an outsize role in America, helping at times to control who can join the military and at what rank; who can enroll in the nation’s most elite private schools, and even who can be executed under federal law. They have also played a large role in America’s public schools, helping to determine from the earliest grades who can access extra help and accelerated learning and who can reap the benefits of high expectations.

After the passage of the Education for All Handicapped Children Act of 1975, schools suddenly found themselves required to label and serve children with a variety of special needs — including learning disabilities and what was then called mental retardation — without enough tools beyond testing to guide them. 

IQ tests’ centrality in many schools is now slowly starting to ebb after decades of research showing their potential for racial and class bias, among other issues. IQ scores can also change significantly over time and have proven particularly unreliable for young children. As a result, more states and school districts have adopted policies and practices that downplay the role of intelligence testing in special education evaluations.

Yet the change isn’t happening fast enough for many parents and researchers who say the tests remain deeply ingrained in the work of school psychologists, in particular, and that they are still regularly misused to gauge young children’s potential and assess whether they are “worthy” of extra help or investment.

“Cognitive testing is kind of the bread and butter of [school] psychologists,” says Tiffany Hogan, a professor and director of the Speech & Language Literacy Lab at the MGH Institute of Health Professions in Boston. “Casting doubts on the use of it is casting doubts on the entire field.”

Related: How a disgraced method of diagnosing learning disabilities persists in our nation’s schools

About a year ago, my daughter, then 5, took an intelligence test as part of a standard education evaluation process. When I looked at the subtest results, a lot of it seemed predictable. My daughter performed especially well in the parts of the verbal section that measure general knowledge (a 5-year-old might be asked the opposite direction from north, for instance). That made sense because we talk constantly about the world around us. Her scores were lower in the portions of the test focused on visual and spatial patterning. That, too, tracked in a family that hates puzzles. 

My (fortunately) low-stakes experience speaks to the long-standing criticism that intelligence tests measure a child’s exposure and early education opportunities, especially for white, middle- and upper-class language and experiences, rather than “innate” intelligence. When the tests became common in public schools in the 1970s and 80s, the goal was they would assess children’s potential, while achievement tests would show how much progress they had made learning grade-level skills. This distinction was codified through a method of evaluating for learning disabilities called the “discrepancy model,” included in 1977 federal guidelines. This model, which I reported on in an article last year for The Hechinger Report and Scientific American, requires a significant “discrepancy” between a child’s IQ and achievement to establish a learning disability, making it hard for children with lower IQs to qualify.

“(School psychologists) had very few tools in the beginning,” said Mary Zortman Cohen, who retired last June after working 34 years as a school psychologist in Boston, “so cognitive testing took on an outsize role in special education.”

IQ tests face a long-standing criticism that they measure a child’s early education opportunities, rather than “innate” intelligence. Credit: Getty Images

At the same time, intelligence tests faced some legal challenges. In the late 1960s, San Francisco school educators labeled a young African American boy named Darryl Lester mentally retarded (what we now call intellectually disabled) after an IQ test. Without fully informing his mother, the school district pulled him out of the regular education program and assigned him to classes focused on life skills. Years later, he recounted in a story published by KQED, San Francisco’s public radio station, that his school days were dominated by recess and field trips.

In the early 1970s, Lester, known in court documents as Larry P., became the lead plaintiff in a California lawsuit alleging that IQ tests discriminated against Black students and were too often used to label them “educable mentally retarded” and remove them from traditional classes. In Lester’s case, he struggled to learn to read but never got appropriate help. 

Lester and the other plaintiffs won their case. In the late 1970s, a judge ruled that IQ tests could not be used to determine special education eligibility for Black students. Despite the victory, Lester was never taught to read, according to the KQED update.

The California case had a big impact on the state with the largest public school enrollment but was an anomaly nationally. Even as California enacted the ban, IQ tests became central across the country to the relatively young and rapidly expanding field of school psychology. To this day, some schools, like Lester’s, withhold access to sufficient academic instruction for many children with low IQs, said Kentucky parent and lawyer Barlow. “It even happens in preschool, this withholding of academic supports.”

In many places, IQ scores have historically been embedded into the definitions of two disability types: intellectual disability (where an IQ score below the low 70s often plays a large role in qualifying a child for the designation) and specific learning disability, such as dyslexia or dyscalculia (where until the early aughts the federal government told states to use the IQ discrepancy model for diagnosis).

Yet cognitive testing is not limited to learning and intellectual disabilities, it is often part of the process for determining a wide range of disabilities, sometimes needlessly so. Children suspected of attention deficit hyperactivity disorder, autism, and emotional and behavioral issues frequently get these tests, and the tests are a standard part of the protocol in many districts whenever a family or school outsider requests a special education evaluation for any reason. “I think what it boils down to is needing something to disqualify kids from services, and this pervasive view that it represents a child’s potential,” said Hogan, the Boston speech and literacy professor. She believes that cognitive testing can provide useful context on a child’s strengths and weaknesses but should never be relied on too heavily to diagnose, or fail to diagnose, a student.

Related: Almost all students with disabilities are capable of graduating on time. Here’s why they’re not

In his 1981 book, “The Mismeasure of Man,” biologist Stephen Jay Gould famously assailed the validity and influence of IQ testing, bringing news of this developing critique to a broader audience. Contrary to the beliefs of some of the original creators and backers of IQ tests, Gould disagreed with the idea that the tests could be used to rank or assign value to people. And he pointed out the structural racism and subjectivity embedded in both the tests and how they were being used to perpetuate societal power structures. His book coincided with other research showing that IQ tests can be biased against Black or low-income students, as well as many others, because they contain language and content that is more familiar to white middle- and upper-income students. 

In the years after “The Mismeasure of Man,” a growing number of education researchers and scientists also began to question the validity and importance of IQ tests in diagnosing learning disabilities. The critiques prompted the federal government to change course in 2004, as part of reauthorizing the Individuals with Disabilities Education Act, strongly recommending that states consider alternatives to looking at the gap between intelligence and achievement scores when determining if a child has a learning disability.

So why does intelligence testing remain so pervasive?

“There’s a science-to-practice lag that can take many years,” said Zortman Cohen, the retired school psychologist. “It takes a long time to infiltrate large, bureaucratic school systems.”

Recent decades have schools shifting to cognitive tests that say they have less built-in bias. Credit: Getty Images

School psychologists say procedures are changing, albeit slowly and inconsistently. Change has been possible in part because of the spread of an evaluation method, known as “response to intervention,” that looks at how children respond to different teaching strategies before making a call as to whether they have a disability.

School psychologist Regina Boland said that in her first job in Nebraska she was forced to rely on the IQ discrepancy model to determine if a child had a learning disability (that district now uses a different approach). “There’s general agreement that it is the least valid method,” she said. “There are some kids who don’t get services under that model who definitely deserve and need support.”

Since moving to Illinois, a state that uses response to intervention as its main method, Boland has a lot more latitude in when to use cognitive tests in the process of determining whether a child has a disability and what help they need.

Under response to intervention, “a lot more is in the control of the school psychologist,” she said. “It’s not perfect, but it’s far better than what we’ve done in the past.”

While Boland believes that “the usefulness of IQ tests is overrated by some teachers,” she wouldn’t want to see them disappear entirely; she uses some form of cognitive testing in about 60 to 70 percent of her initial evaluations.

“I find it useful when kids who are lower functioning and may have intellectual disabilities come across as defiant and disrespectful, when really it’s a matter of them not understanding the information,” she said. “An IQ test can look beyond assumptions and capture abilities that are not assessed in the classroom.”

Related: What research tells us about gifted education

Not every intelligence test is created equal. Recent decades have seen a growth in cognitive tests with the goal of minimizing some of the race and class bias that plagued their predecessors.

Boland said she’s selective about which cognitive tests she uses. She avoids the Wechsler Intelligence Scale for Children (WISC), a commonly used test. She finds it loaded with language that’s more familiar to middle-class white children and an overall bias “against cultural and linguistic minorities.” Research studies have critiqued the test in the past for including questions such as: “Who was Charles Darwin?” and “What is the capital of Greece?”

“I might use the Weschler if it’s a middle-class white kid,” she said. Fortunately, Boland added, there are more options than ever for cognitive tests that are “less language loaded.”

Jack Naglieri, an emeritus professor at George Mason University and a creator of some of those alternative tests, including the Cognitive Assessment System, said he noticed decades ago how blurry the distinction was between achievement tests and intelligence tests. Both, he said, test a child’s accrued knowledge, not innate capacity.

His tests try to measure “thinking rather than knowledge,” as he puts it.

As an example, his tests would attempt to assess a child’s ability to see patterns in a series of visual shapes (see diagram) while a traditional IQ test might require a child to show vocabulary and numeracy knowledge to answer a comparable question. “The field is mired in the past in 100-year-old technology that people think is good because it’s been used for so long,” he said, “not because it really works.”

Try a few questions yourself

Many psychologists believe that traditional intelligence tests too often measure what a child already knows, not how well they can think. Jack Naglieri, a psychologist and creator of cognitive assessments, offered examples of questions that try to assess thinking rather than measuring pre-existing knowledge. 

Click thru slideshows to see answers

Source: Jack Naglieri, emeritus professor, George Mason University

Educators and school psychologists need to rely less on intelligence tests, use them more wisely in some instances, and ensure that they are choosing the least biased tests. But they cannot bear this responsibility alone. States and school districts play an enormous role in setting the parameters under which school psychologists must operate. Some district and state officials have denied children access to special education services by setting limits on how many children qualify — with cognitive testing at times playing a problematic role as gatekeeper. Boland, the school psychologist, for example, had more freedom to exercise her professional judgment when she moved to a state that didn’t mandate a heavy reliance on intelligence testing in diagnosing certain disabilities.

Training programs for school psychologists also must change, at least those that still include outdated materials or simplistic guidance on cognitive testing. “Strict cognitive testing is a poor way of addressing the pieces of the puzzle for any one kid,” said Zortman Cohen. “It takes a lot of good training to understand how to do this well.”

In addition to systemic and policy changes, we also need a shift in mindset. Embedded in too many schools’ practice and policy, to this day, is the idea that an intelligence test score can somehow measure human potential. It does not. At their best, these tests provide a snapshot in time of a child’s cognitive strengths and weaknesses. But it is fundamentally unjust to deploy them in ways that conflate a score with a capacity for learning, and exclude children from full participation in that learning process by denying them access to an academic curriculum, or extra help learning to read. To continue to do so implicitly upholds the wild, ill-informed dreams of IQ exams’ 19th and early 20th century creators, many of them eugenicists who believed civilization would advance only upon social and educational exclusion and segregation determined by untested tests.

For nine months, Kentucky parent Barlow despaired that her son might fall victim to this kind of exclusion. She considered filing a legal complaint against the district, attended meeting after meeting, and reached out to national and local parent advocates alike — all to no avail. Then, a friend of hers was appointed principal of the neighborhood school — shortly before her son was scheduled to start kindergarten. The district relented, agreeing to let him attend the school.

Today he’s in seventh grade and receives regular instruction with his peers in math, English, science and social studies, with modifications. Barlow said he has made tremendous gains in areas including health, math, and reading. His learning enriches his life on a daily basis. It would not have been possible without exposure to a mainstream curriculum and peers, Barlow said.

“To see the bright lights go off when he is able to read the title of a TV show or the name of a song or the food he wants to eat on a menu — it’s like the angels are singing,” she said. “He can access the world because he can read.”

This story about intelligence testing in schools was produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education.

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