Monthly Archives: April 2016

Is mindful meditation good for learning?

If you work in or near a school—or if you often read this blog¹—you have surely heard about meditation’s potential benefits for just about everything: executive function, stress reduction, strategic backgammon decision making. (I think I made that last one up.)

So what do you make of an article with this title: “Increased False-Memory Susceptibility After Mindfulness Meditation”?

If you’re like me, such an article might give us pause. If meditation promotes “false-memory susceptibility” of any kind, it must be bad for learning. No? Time to call a halt to all those meditation programs. Am I right?

List vs. Gist

Here’s a fun game you might try at your next dinner party.

I’m going to give you a list of words, and your job is to remember them.² Ready? Here we go:

Table, sit, legs, seat, soft, desk, arm, sofa, wood, cushion, rest, stool 

A few minutes from now, when I ask you to write all those words down again, you’re likely to remember several of them. You’re also likely to include a word that wasn’t actually on the list: chair.

After all, while the word “chair” doesn’t appear in that list, it is implied by or associated with all the other words. Tables and desks and sofas and stools often accompany chairs; people sit on chairs; chairs have legs and arms and cushions.

In other words, when you remember that list of words, you remember not only the specific items on it, but also its gist. The gist includes the idea of “chair,” even though the list itself did not.

The Beginning of the End?

Brent M. Wilson and his colleagues wondered if meditation would increase the formation of gist memories. Their thought process went like this:

Because meditation promotes judgment-free observation of the world, people who have recently meditated might be less likely to distinguish between (that is, form judgments about the source of) internally and externally generated words. If this hypothesis is correct, meditators are less likely to see differences between (external) list memories and (internal) gist memories. They are therefore likelier to include gist words when they join us for our dinner party game.

To test this idea, Brent Wilson invited 140 college undergraduates to dinner. (Ok, no. The students did this exercise in a psychology lab. You have to admit, however, that my version sounds more fun.)

For fifteen minutes, half of the participants were invited to “focus attention on their breathing without judgment”: that is, they were guided through meditation. The other half spent fifteen minutes in a mind-wandering exercise: a common control task in studies of mindful meditation.³

Sure enough, when Wilson tested the post-meditation students, they were likelier to include gist words than students in the control group. Seemingly, meditation promotes the formation of false memories.

To make doubly sure, Wilson tried another research paradigm as well. Students saw 100 words on a computer screen; each word was half of a common pair (shoe/foot, for example, or hot/cold). They were then shown another 100 words—half of which were on the first list, and half of which were pairs of words from that list. Students who meditated were likelier than those in the control group to “remember” a new word as if it were an old one.

So, there you have it: meditating increases false-memory susceptibility. By definition, anything that promotes false memories harms learning. No doubt, Wilson’s study is the beginning of the end of school-based meditation.

Let Me Count the Ways

And yet, perhaps you do have some doubts. So do I. And here’s why…

First, it’s important to emphasize that Wilson and his crew never draw the conclusion that I have implied. As teachers, we might read the title of the article and plausibly extrapolate that meditation must be a terrible idea. But the study’s authors never say so.

And, even if they did, we must keep in mind that this study is…one study. The effects of mindfulness have been researched in hundreds of studies. Given that volume, we should expect some studies to show negative results, and others to show neither benefit nor harm.

In short, we should be interested in bodies of research as well as individual studies.

Second, when we read the specifics of this individual study, we can see how small the effects really are. In that dinner party game, for example, 26% of the control group thought that they “remembered” gist words, whereas in the meditation group, 34% did. This increase is statistically significant, but hardly alarming.

(For you statistics junkies, the Cohen’s d values are 0.38 and 0.28 in the two studies I described. Again: not nothing, but not much of something.)

Third: say it with me now—context always matters.

In some classes, a gist memory might be a bad thing. For example, a colleague of mine has her students learn a song to help them memorize all English prepositions. In this case, she doesn’t want her students to add to that list by forming a gist memory. Instead, she wants them to remember all the words in the song, and only the words in the song.

Specifically: “although” might feel like a preposition, and a student’s gist memory might try to incorporate it into that list. But “although” isn’t a preposition; it’s a conjunction. For this reason, Wilson’s research suggests that my colleague might not have her students meditate just before they learn the song. In this case, gist memory detracts from learning.

In other classes, however, gist memory might be my goal. When I teach Macbeth, for example, I want my students to recognize how Shakespeare constantly pits forces of order against forces of chaos. Every page of text includes multiple instances.

For instance: Lady Macbeth is extravagantly polite to King Duncan when he arrives in her castle. And yet, her display of social order masks her determination to commit regicide—the ultimate form of social disorder.

While I certainly want my students to remember specifics from the text, I also want them to feel the bigger picture, to identify both trees and forest. In other words, the event that Wilson calls “false memory” a teacher might call “learning.” Wilson’s research, thus, suggests that I might want my students to meditate before Macbeth class.

Context always matters.

Or, to paraphrase my wise blogging colleague Rina Deshpande, “our role as educators is not to dismiss or adopt a practice right away, but to consume with care.”⁴

Balancing Curiosity with Skepticism

I’ve explored this study in some detail because it points to helpfully contradictory points:

A. Although mindful meditation has gotten a lot of recent buzz, teachers should pause before we make it a part of our practice. All classroom techniques have both benefits and perils, and we should seek out information on both. In this case, for example, meditation might lead to a particular sort of false memory.

B. Terminology from psychology and neuroscience—terminology such as “false memories”—might be unhelpful, even misleading. In some cases—lists of prepositions—we don’t want students to create gist memories; in other cases—themes of literary works—we do. But alarming phrases like “false memories” shouldn’t distract us from thinking through those possibilities.

In other words: “false memory” sounds like a bad result, but once we realize that “gist memories” are a potentially useful kind of “false memory,” the phrase isn’t so scary any more.

C. For this reason, we must always look at the specific actions performed by specific study participants. If an article’s title claims that “high ambient temperature reduces learning,” you might find that interesting; your classroom often seems unreasonably warm, and your students unreasonably sluggish. However, if you read the study’s particulars, you might find that mice learn a water maze faster in cold water than in warm water. Because your students aren’t mice, aren’t learning mazes, and—I’m assuming—aren’t up to their necks in water, this study may not really apply to you. Perhaps you’ll find more relevant research elsewhere…⁵

Once More, With Feeling

So, to return to my initial question: Is mindful meditation good for learning?

My answer is: that’s too big a question to answer sensibly. Reading studies (like Wilson’s), we can balance specific potential perils of meditation against the specific potential benefits that Rina has wisely summarized.

References & Further Reading

1. Deshpande, R. What we’re getting right—and wrong—about mindfulness research. [Blog]
2. Roediger, H.L., & McDermott, K.B. (1995). Creating false memories: Remembering words not presented in lists. Journal of experimental psychology: Learning, Memory, and Cognition, 21 (4), 803-814. [Paper]
3. Wilson, B.M., Mickes, L., Stolarz-Fantino, S., Evrard, M., & Fantino, E. (2015). Increased false memory susceptibility after mindfulness meditation. Psychological science, 26 (10), 1567-1573. [Paper]
4. Deshpande, R. What we’re getting right—and wrong—about mindfulness research. [Blog]
5. I made this study up too. Just for fun, here’s an article on the complex relationship between room temperature and working memory: Sellaro, R., Hommel, B., Manai, M., & Colzato, L.S. (2015). Preferred, but not objective temperature predicts working memory depletion. Psychological research, 79 (2), 282-288. [Paper]

To commemorate World Teacher’s Day last year, Reuters’ photographers shared images of students around the world in different classrooms—including those without electricity, books, chairs, or walls. These photos serve as a reminder of extreme global inequality in the distribution of educational resources. But they also suggest that few physical materials are strictly necessary for building a rich world of learning.

While learning can potentially take place anywhere, aspects of the immediate physical environment, from the arrangement of desks to the air quality of the neighborhood, may impact student learning. But how much does the physical environment relate to students’ academic growth?

Designed to address this question, the Holistic Evidence and Design (HEAD) Project published its results in 2015 and was named one of Edutopia’s Education Research Highlight studies of the year. This study deliberately incorporated geographic and socioeconomic diversity in their sample by collecting information about 3,766 students from 1st through 6th grade at 27 schools in three districts!¹

The results? Taking into account reading, writing and math scores, the HEAD study estimates that moving an “average” elementary school student in the UK from the least effective learning environment to the most effective one has the impact of more than half a school year of growth.

Rather than examining the impact of a single factor like air quality, this study examined a wide array of school and classroom features. Taking this holistic stance and measuring student growth over the course of a school year allowed the researchers to answer two other key questions:

1. Which aspects of the physical environment seem to relate most strongly to student learning?
2. What does this suggest about how to improve schools?

First and foremost, they found that the immediate classroom environment, rather than the overall school environment, was much more strongly related to student outcomes.^1,2 The authors of the study point out that this may be because they conducted research in the elementary grades, where students spend the majority of the school day in a single classroom. Further research with secondary students, who spend more time in hallways and moving between many different classrooms, may support different findings.

To gather their data and break down their results, the researchers considered elements of naturalness, individualization, and complexity in the classroom environment.

Naturalness: Let there be Light

Across all aspects of classroom design in the study, lighting had the strongest link to student learning.^1,2 The availability of natural daylight and/or good quality electrical lighting were important. The researchers recommend keeping classroom windows free of obstruction from furniture or displays, allowing in natural light while actively monitoring glare during the day as needed with blinds.¹

Good lighting is of course critical to sight, but different levels of light also provide signals to the body related to alertness and attention via the circadian system. This system is related to sleep/wake cycles, as well as micro-shifts in hormones over the course of a day.³ In addition to supporting attention during the day, we speculate that good lighting may support learning and memory by promoting quality sleep at night.

Air quality (recently covered by my colleague Gabriella Hirsch in this post) and temperature were also strongly linked with student learning. Two aspects of classroom design with weak links to student learning include sound factors (such as noise pollution from busy nearby streets) and the availability of nature (such as natural views from classroom windows).¹

Individualization: Find the Flair

Having a distinctive look and feel to the classroom was related to improvements in student outcomes.^1,2 This “distinctiveness” may be accomplished by a unique, built-in aspect of the classroom, such as shape or layout. It can also be accomplished by displaying student work and/or by having special areas of the classroom with students’ names and spaces, such as drawers or lockers.

Why might classroom uniqueness and personalization matter? The authors of the HEAD study suggest these issues may increase students’ sense of classroom ownership.¹ This hasn’t been shown conclusively, as many explanations are possible. One study of kindergarteners and 1st graders suggests that environmental personalization may be related to higher self-esteem.⁴ A separate study of adults suggests that personalization may buffer emotional exhaustion in workplace environments that have little privacy.⁵ While current evidence is limited, these studies support the hypothesis that personalization in working environments may support psychological well-being across the life span.

Another important aspect of classroom individualization in the HEAD study was flexibility; the authors of the study recommend that teachers create clearly defined classroom zones to support different types of activities and/or small group instruction, particularly in the younger elementary grades.¹

Complexity: Hit the Sweet Spot

How visually complex should classrooms be? On average, classrooms in the HEAD study that were Spartan—filled with blank, white walls—didn’t do so well. Yet, on average, ones with every inch of the walls spattered with color didn’t do well, either. It seems that there may be a “sweet spot” between minimalism and high-intensity chaos that is associated with better student outcomes. The researchers recommend keeping 20-50% of the wall space clear and including some elements of color in the classroom environment (which also sounds aesthetically pleasing!).¹

One study has found that in highly decorated classrooms, as compared to very sparse ones, kindergarteners score worse on teacher-administered tests and spend more time off task. The authors of this study suggest that visual complexity can be distracting to young children.⁶ However, other scientists suggest that these results were driven by the newness of the décor rather than visual complexity itself.⁷ No study has yet comprehensively examined the effects of various levels of classroom décor complexity on student attention across grade levels, and further research may be needed to understand and support the “sweet spot” hypothesis.

One caveat
The HEAD study aims to describe what was happening in classrooms and correlates student outcomes with different classroom types. Like other studies of this kind, it can’t establish causality between different classroom environments and student learning. They can’t rule out the possibility that something else might be driving their results. For example, it may be that teachers who attend to classroom design also tend to create effective visual displays in worksheets and/or more organized activities that better support student learning.

What’s next? Probably Pinterest
As you consider your own teaching and learning environments for the final stretch of spring quarter or the next school year, keep the design elements of naturalness (especially light), individualization/personalization, and the level of complexity in mind. And know that the time and care you put into creating a great space to work and learn may make a difference.

References & Further Reading

1. Barrett, P., Davies, F., Zhang, Y., & Barrett, L. (2015). The impact of classroom design on pupils’ learning: Final results of a holistic, multi-level analysis. Building and Environment, 89, 118–133. [Paper]
2. Barrett, P., Zhang, Y., Davies, D. F., & Barrett, D. L. (2015). Clever Classrooms. [Report]
3. Boyce, P., Hunter, C., & Howlett, O. (2003). The Benefits of Daylight through Windows. Lighting Research Center, 1(1), 1–88. [Report]
4. Maxwell, L. E., & Chmielewski, E. J. (2008). Environmental personalization and elementary school children’s self-esteem. Journal of Environmental Psychology, 28(2), 143–153. [Paper]
5. Laurence, G. A., Fried, Y., & Slowik, L. H. (2013). “My space”: A moderated mediation model of the effect of architectural and experienced privacy and workspace personalization on emotional exhaustion at work. Journal of Environmental Psychology, 36, 144–152. [Paper]
6. Fisher, A. V, Godwin, K. E., & Seltman, H. (2014). Visual Environment, Attention Allocation, and Learning in Young Children: When Too Much of a Good Thing May Be Bad. Psychological Science, 25(7), 1362–1370. [Paper]
7. Imuta, K., & Scarf, D. (2014). When too much of a novel thing may be what’s “ bad ”: commentary on Fisher, Godwin, and Seltman (2014), 5 (December), 1–2. [Commentary]

• Evans, G. (2006). Child development and the physical environment. Annu Rev Psychol, 57, 423–451. [Paper]

I have a confession to make: I was an avid “visual learner” all through grade school and high school. No matter the assignment or the subject, if I could make a diagram or chart about it, I would. I even dabbled with verbal learning in elementary school: my Dad and I would make up songs about the words that would be on my weekly spelling tests and sing them in the car on the way to school.

So did my penchant for (sometimes overly creative) learning styles help? Possibly, but not for the reasons you’d think.

Over the past few years, new research within neuroscience and psychology has begun to show that teaching in a person’s preferred learning style actually has no positive effect on their learning. That doesn’t mean you can’t enjoy one style more than another, but contrary to popular belief, enjoying it more does not appear to strongly predict success.

You’re not alone

When I first discovered the mounting evidence against catering to preferred learning styles, I was pretty surprised. My entire educational life had been structured around this idea. It seems almost intuitive to believe in such a concept. Not only do most of us have a desire to learn and to be seen as unique, but we also have a preference for how we receive information. On top of that, many of our teachers reinforced these ideas almost daily in their lesson plans.

But who can blame them?

With pressure from parents who understandably want their children to receive a tailored education, and teachers who are sympathetic to each and every students’ needs, preferred learning styles – or more specifically, the idea that we learn better when the information we are receiving is customized to our preferred way of learning – fills these voids. Not only are students receiving information in a unique way, but teachers also begin to feel that the information they are teaching is finally being comprehended by all of their students.

In 2014, an international survey¹ found that 96% of teachers all over the world believed in the value of teaching to preferred learning styles. That’s an amazingly high number that publishers and corporations have taken advantage of: with hundreds of popular books on the topic, companies trying to sell you ways to measure learning styles, teacher training programs, and international associations, no wonder so many people believe in this idea. This idea seems so true, that many researchers have spent tremendous effort exploring it, while others seem to simply believe it without sufficient evidence – in the past five years alone more than 360 scientific papers have cited learning styles.

The evidence is clear

In 2008, a team of cognitive neuroscientists decided to review all of the scientific evidence that had been gathered or published about learning styles – both for and against the concept. The results were clear: teaching in a person’s preferred learning style had no beneficial effect on their learning. As one of the researchers put it ², “the contrast between the enormous popularity of the learning-styles approach within education and the lack of credible evidence for its utility is, in our opinion, striking and disturbing”.

So, is there any evidence that supports the learning style concept? A little, but very few studies ² have produced significant results. While studies in support of the preferred learning style idea should be able to show that people of one preferred learning style learn better when taught in this specific way, most of the evidence ³ actually contradicts this.

When researchers attempted to compare two groups, and therefore two preferred learning styles, in order to see the rate at which these groups learned the same material, they often found that both groups performed better when they were both taught in one particular style, rather than what they preferred. Why is this? This research suggests that the most effective way for people to learn is actually based on the material being taught to them and not how they prefer to learn. Imagine if you were only ever taught long division verbally, or if you attempted to learn a new language with only picture cards – things would be pretty difficult.

Evidence has shown that the questionnaires used are unreliable, mainly because they rely heavily on an individual’s self-reporting. While individuals may think that they are learning better when taught in their preferred style, the results actually show that there is a very poor correlation with this and their actual performance. Interestingly, a more accurate predictor of someone’s performance is actually their performance on past tests and assignments, rather than their learning style aligning with your teaching style.

Learning Styles, Multiple Representations & Individual Differences

So why are so many so attached to the idea of learning styles? And why did I believe that making up songs with my dad was so much more effective than reading a textbook?

One answer, it seems, is not the difference between the way we learn, but the ways in which we are similar. Research has shown that most typically developing people will respond strongly to multiple modes of teaching. In other words, if a proponent of learning styles decides to teach the same material using visuals, activities, and words, everyone in the class is likely to benefit from the multiple representations of information. This is a concept explored more fully by many research groups and non-profits, such as CAST’s Universal Design for Learning Platform.

In other words, rather than trying to tailor curriculum to each student’s “learning style”, it may be more helpful (and efficient) to incorporate some of the strategies that are likely to improve learning for all students – such as getting students to explain concepts to themselves or aloud (see my previous article here). Research has shown that almost all students learn from a mixture of verbal and visual, rather than one alone. Other research ⁴ has found that learning can be improved by combining different activities that relate to the same subject, such as having students participate in something creative like drawing or painting along with more passive tasks like reading. In their book, Visible Learning and the Science of How We Learn, Hattie and Yates emphasize this in the following passage:

“We are all visual learners, and we all are auditory learners, not just some of us. Laboratory studies reveal that we all learn when the inputs we experience are multi-modal or conveyed through different media.”

While there’s very little evidence that supports the benefits of matching your teaching style to your students’ preferred learning style, there is evidence that shows that tailoring teaching style in other ways may improve learning. For example, one study ⁵ found that those new to a subject learn better from studying examples, whereas individuals with more knowledge of the subject learn better by solving problems themselves.

There are countless other factors that may have an impact on an individual’s learning trajectory (see Center for Individual Opportunity), often referred to as “Individual Differences”. Unfortunately, these differences can’t be accounted for based on preferred learning styles, and by releasing our grip on this myth, we can work towards building strategies based on more compelling evidence.

Teach to students’ intellectual weaknesses, rather than their strengths

Most importantly, in many cases, this isn’t just a harmless misunderstanding. Perpetuating the myth of preferred learning styles could actually harm students more than it can help them. One important point Scott Lilienfield and colleagues have emphasized in their book 50 Great Myths of Popular Psychology, is that the concept of preferred learning style actually “encourages teachers to teach to students’ intellectual strengths rather than their weaknesses.”

This suggests an alternative approach: rather than catering to how students think they learn best; challenge them! Allow students to focus on their shortcomings rather than to avoid them. The differences between students aren’t defined by their learning style, but are determined by their prior knowledge and the patterns they recognize while learning.

And while it is still important for teachers to be attentive to the individual and unique differences of each student, evidence on learning styles suggests that they aren’t producing the results students deserve. Rather than putting all of your effort into a teaching method that isn’t supported by science, use your limited resources to use methods that have been proven effective, such as analogies ⁶ or praising effort instead of intelligence ⁷.

And most importantly, don’t stop tailoring your teaching style! Just do it wisely.

 

References

1. Howard-Jones, P. A. (2014). Neuroscience and education: Myths and messages. Nature Reviews Neuroscience Nat Rev Neurosci,15(12), 817-824. [Paper]
2. Pashler, H., Mcdaniel, M., Rohrer, D., & Bjork, R. (2008). Learning Styles: Concepts and Evidence. Psychological Science in the Public Interest,9(3), 105-119. [Paper]
3. Massa, L. J., & Mayer, R. E. (2006). Testing the ATI hypothesis: Should multimedia instruction accommodate verbalizer-visualizer cognitive style? Learning and Individual Differences,16(4), 321-335. [Paper]
4. Schmeck, A., Mayer, R., Opfermann, M., Pfeiffer, V., & Leutner, D. (2014). Drawing pictures during learning from scientific text: testing the generative drawing effect and the prognostic drawing effect Contemporary Educational Psychology, 39(4), 275-286 [Paper]
5. Kalyuga, S., Ayres, P., Chandler, P., & Sweller, J. (2003). The Expertise Reversal Effect. Educational Psychologist, 38(1), 23-31 [Paper]
6. Glynn, S. M. (1991) Explaining Science Concepts: A Teaching-with-Analogies Model in Glynn, S. M., Yeany, R. H., & Britton, B. K. (Eds). The Psychology of learning science. Hillsdale, NJ: L. Erlbaum Associates. [Book]
7. Gunderson, E. A., Gripshover, S. J., Romero, C., Dweck, C. S., Goldin-Meadow, S., & Levine, S. C. (2013). Parent Praise to 1- to 3-Year-Olds Predicts Children’s Motivational Frameworks 5 Years Later. Child Development,84(5), 1526-1541 [Paper]

 

It’s buzzing all over the news: the heroic act of pediatrician, Dr. Mona Hanna-Attisha, and her colleagues bringing to light the dangerous effects of lead-contamination in Flint’s water system.¹

Lead is a long-known neurotoxin with especially damaging effects on adult and child cognitive development (and therefore reason for serious alarm in Flint, Michigan).

Lead toxicity in drinking water is measured in “parts per billion” (ppb) with most researchers claiming that no amount of lead is acceptable for ingestion or exposure. Even with the generous consideration of 5 ppb in drinking water as “cause for concern,” extreme circumstances in Flint show that hundreds of houses have registered at 27 ppb in their water supply. Some homes fall between a totally jaw-dropping 1,000 and 5,000 ppb– what the U.S. Environmental Protection Agency considers “toxic waste.” For an alarming visual explanation, read more by Christopher Ingraham here.²

The effects of lead-contaminated water and environmental lead exposure are exceptionally harmful to adult health and even more so to young growing children. In this article, we’ll review the meaning of neurotoxicity and expose research on lead’s long-term harm to cognitive development.

What is “neurotoxicity”?

Neurotoxicity is damage caused by particular natural or artificial substances (also called “neurotoxicants”) on healthy nervous system functioning. Depending on severity, a neurotoxin can kill nerve cells, therefore diminishing development and function of the brain and other parts of the nervous system.³

One of many concerns with neurotoxins like lead is their often invisible, immediate symptoms. When effects do appear soon or later, symptoms can range from impairment of physical motor skills such as manual dexterity and leg paralysis to cognitive and behavioral problems. If severe enough, neurotoxin exposure can be fatal.

Lead’s long-term effect on cognitive function

In a groundbreaking longitudinal study led by Dr. Brian Schwartz at Johns Hopkins University, declines in learning and memory were found to be associated with lead exposure many years after exposure took place, suggesting that lead’s dangerous impact on the body is progressive and lasting.

Over the course of three years in the study, researchers tested 535 former lead workers and 118 controls (participants who had not been exposed to lead) for cognitive decline each year using a neurobehavioral battery. Additionally, blood tests measured amount of lead present in the tibia bone (one of two bones between the knee and foot) to estimate “peak tibia lead,” or levels of lead in the tibia at the last time of exposure to lead. Lead is usually eliminated from bones over years, which can mask the severity of original lead exposure. For this reason, instead of solely observing current lead levels researchers wanted to account for level of toxicity during the time of peak lead exposure to see if this had any impact on cognitive decline.

Schwartz’s longitudinal study offered two very important findings: (1) Controlling for age, former lead workers (most of whom had not worked with lead for at least 16 years) had much larger annual declines in neurobehavioral test scores and cognitive decline than did the controls who had not been exposed to lead. (2) Peak tibia lead levels in former lead workers predicted their annual cognitive decline in learning and memory, executive function, and manual dexterity. The higher the peak lead level, the steeper the rate of cognitive decline.⁴

Given evidence of lead’s toxic impact on adult cognition even decades after lead exposure, imagine the impact on cognitive development of young growing children.

Lead’s impact on child cognitive development

Over the last twenty years, the amount of lead required in a child’s blood to consider her at an “elevated blood lead concentration” has gradually dropped. In other words, with each passing year it’s becoming clearer that amounts of lead once considered negligible in a child’s blood are actually severely harmful for body and brain development.

A number of studies have illustrated how extreme levels of lead concentration in the blood can strongly affect intellectual processing and behavior in young children and, in some cases cause encephalopathy, a brain-altering disease. In more recent research, however, we see that as seemingly small an amount as 10 micrograms of lead (.01 thousandths of a gram) per deciliter of blood can have persistent and potentially irreversible negative effects on health and cognitive development in children.

In a longitudinal study published in the New England Journal of Medicine, nearly 200 young children previously identified blood lead concentrations of <10 micrograms per deciliter were assessed first at age three and again at age 5 for IQ (memory, vocabulary, spatial pattern analysis, and quantitative reasoning). Blood lead levels (BLLs) were measured every six months throughout the study.

Results revealed that the higher the levels of lead in a child’s blood, regardless of how it was measured in the study, the lower the IQ score of the child. Controlling for a variety of extraneous influences, peak blood lead concentration, average lead concentration through the first five years of life, and blood lead concentration on the day of IQ testing all had a significant inverse correlation with a child’s IQ. In other words, the higher the markers of lead exposure, the lower the markers of intelligence. An important focus of this study was confirming that any amount of lead in the blood– even very low traces – had an inverse association with IQ in children.⁵

In a related study in Mexico City, researchers were interested in lead’s impact on mental and psychomotor development on infants. Among one and two year-olds whose blood lead concentrations were less than 10 micrograms per deciliter, researchers found an inverse relationship between blood lead levels and their mental development and psychomotor development. These findings further support that, even with previously considered acceptable amounts of lead exposure, lead’s neurotoxic effects on mental and motor development are present in infancy.⁶

In studies such as the aforementioned, evidence from measuring blood lead levels and cognitive performance strongly suggest that infants and young children are at high risk from any level of lead exposure, but causal claims are tough to make from observational research.

Research in neuroscience to continues to explore the neurological deficits caused by lead exposure. In a 2011 study published in the Journal of Hazardous Materials, scientists observed the neurological effects of lead exposure on embryonic development of zebrafish, an abundant fish species that shares 70% of our genetic code and is now commonly used in medical research.⁷ The study revealed that zebrafish exposed to lead commonly displayed symptoms such as slow swimming movements and impaired escape action. Scientists Dou and Zhang attribute these findings to inhibited neurogenesis (nerve cell birth) and increased apoptosis (nerve cell death) resulting from lead-induced neurotoxicity.⁸

While the results of this animal study offer some insight about the harmful effects of lead on neurodevelopment, it’s unnerving to realize just how profound the damage may be on the health of Flint citizens.

How can we help Flint through the crisis?

It’s easy to feel powerless against lead contamination given the research, but there are ways to help. In a recent article featured on the Huffington Post, Sandra Grossman shares quick and impactful ways to support Flint amid its emergency.⁹

• To support immediate need of clean water in Flint, consider donating to the United Way of Genesee County. 100% of donations will be used toward purchasing filters and bottled water that goes directly to Flint communities.

• To support ongoing research on child health and development including interventions for lead contamination, consider donating to the Flint Child Health & Development Fund. Mona Hanna-Attisha herself is the founding donor.

For more ways to help, read the full article here.

In light of the evidence and the 8,000+ children exposed to lead-contaminated water, it’s clear why Dr. Hanna-Attisha is regarded as hero.

 

References & Further Reading

1. Gupta, S., Tinker, B., and Hume, T. (January 28, 2016). “‘Our mouths were ajar’: Doctor’s fight to expose Flint’s water crisis.” CNN.com. [Article]
2. Ingraham, Christopher. (January 15, 2016). “This is how toxic Flint’s water really is.” The Washington Post. [Article]
3. National Institute of Health: National Institute of Neurological Disorders and Stroke. NINDS Neurotoxicity Information. Retrieved on January 31, 2016. [Link]
4. Schwartz, B., Stewart, W., Bolla, K., Simon, P., Bandeen-Roche, K., Gordon, P., . . . Todd, A. (2000). Past adult lead exposure is associated with longitudinal decline in cognitive function. Neurology, 55(8), 1144-50. [Article]
5. Canfield RL, Henderson CR, Cory-Slechta DA, Cox C, Jusko TA, Lanphear BP. 2003. Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter. N Engl J Med 348(16):1517–1526. [Article]
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