We can be attentive to only a small sliver of the world.
We’re constantly surrounded by so much noise, so many smells, so many different colors, textures, tastes. The amount of sensory information that we’re bombarded with every moment would be overwhelming if we weren’t so good at ignoring our environment.
Consider smells. Chemicals waft through the air, bind to olfactory receptors in our nose, and cause a signal to ping our brain: there’s the floral scent of an ethyl acetate here … But, if we stay near the source of that chemical, our brain will keep receiving that signal. Thankfully, this information is discarded by our subconscious minds. As long as the types of smells in a space aren’t changing, we soon notice nothing.
If our clothes feel the same against our skin from one moment to the next, all the tactile information being sent from the surface of our body is similarly ignored. But the information is still there. If we focus your attention on your shirt, you can feel it.
In The Pearl, John Steinbeck reveals how this glut of information can cause us to be hoodwinked. A poor diver becomes suddenly wealthy when he finds a giant pearl. The diver’s infant child was stung by a scorpion and has begun to recover … but a greedy doctor would rather the child receive an expensive cure. The doctor knows that he can fool the diver by drawing his attention to details that never seemed important before.
“It is as I thought,” [the doctor] said. “The poison has gone inward and it will strike soon. Come look!” He held the eyelid down. “See – it is blue.” And Kino, [the diver], looking anxiously, saw that indeed it was a little blue. And he didn’t know whether or not it was always a little blue. But the trap was set. He couldn’t take the chance.
If we scrutinize the world, we can always find something that looks strange.
When I was in high school, I had to get a medical physical each year. Those cost $5 – a school nurse would measure my blood pressure, listen to my heart, and look at the curvature of my spine. I felt healthy enough when I signed up for these physicals, and the nurses invariably agreed. Even repeatedly-concussed football and soccer players were given a clean bill of health.
This $5 exam was insufficient to find anything wrong with us. But if we’d been subjected to a $25,000 battery of diagnostic scrutiny instead, I’m sure we’d have seemed flawed.
Indeed, in a recently-published study designed to shill the new $25,000 physical from a company called “Health Nucleus” in California – which includes DNA sequencing, metabolite analysis, full-body MRI, two weeks of heart monitoring, and more – 40% of their seemingly-healthy study participants were diagnosed with “something seriously wrong.” In several study participants, doctors found clusters of aberrant cells: pre-cancer.
In sexually-reproducing multicellular organisms, most cells carry DNA instructions to sacrifice themselves for the sake of the whole. Some of these instructions code for contact inhibition, which means that cells stop growing when their edges bump into neighbors. Other DNA sequences code for apoptosis, which means that cells commit suicide once they’re no longer needed.
But the mechanism for transmitting these instructions is imperfect. DNA is copied again and again by jiggling protein machines called polymerases, and these make about 60 mistakes each time they copy our genomes. Worse, DNA is copied from copies, so the mistakes pile up over time. Like classroom handouts that have been photocopied from photocopies so many times that the words blur into static, DNA sequences that instruct our cells to cooperate can become unreadable. At which point a cell is cancerous.
Cancer cells continue growing without regard for the neighbors they’re crowding. They carry on dividing – spewing forth copies of themselves – long after a team-player would’ve snuffed itself.
Most human adults harbor cancer cells. All the time, they lurk in us. And our immune systems destroy them. Chemotherapy drugs do not kill cancerous cells – they slow the growth of all cells, giving a patient’s own immune system time to fight the menace.
So it’s unsurprising that doctors found pre-cancer in some of the study participants who underwent this $25,000 physical. Study participants were as old as 98. Their average age was 55. After so much time alive, of course some of their cells had gone bad.
Early detection of cancer does boost a patient’s chance of survival, but sometimes in a trivial way. Healthy patients whose immune systems would have destroyed a population of aberrant cells without any intervention … who might never have realized that anything was ever wrong … are counted as “cancer survivors.” Extremely sensitive diagnosis can identify cancers early enough to be cured, but has the drawback of mis-labeling healthy people as diseased.
Every diagnosis of disease leads to harm – from worry, from the risks inherent in all medical treatment – and so has to be balanced against the expected outcome from doing nothing. With some conditions, doing nothing would be deadly. But by scrutinizing healthy people, you can always find something that looks strange. Of course you’ll find “evidence of age-related chronic disease or risk factors” when you subject older people to a $25,000 battery of medical tests. If you aggressively treat all of these, you’ll cause more harm than good.
Because overdiagnosis can cause so much harm, the search for pre-cancer reminds me of the search for pre-criminals. We can always find something wrong when we look hard enough.
I assume the researchers investigating children to find “pre-criminals” mean well. I can imagine a world in which at-risk children are given more resources. If it’s true, for instance, that a brief assessment of 3-year-olds or surveys filed by the teachers of 6-year-olds can predict future criminal behavior, we should cut spending on prisons and law enforcement to fund childhood nutrition, education, and enrichment instead.
Instead, we respond to intimations of future disobedience by watching people more closely.
Our predictions of criminality become self-fulfilling: lifelong mistrust makes people criminals. The racial injustice of mass incarceration is caused in part by unequal enforcement. As far as we know, U.S. citizens of all ethnicities break laws equivalently often, but police scrutinize minority neighborhoods more closely, so that’s where they find crimes.
Similarly, when an elementary teacher decides that a student is trouble, that student gets scrutinized. Equivalent misbehavior reaps unequal discipline. In the U.S., children in preschool are targeted for school suspension based on the color of their skin. A suspension disrupts education, pushing students further behind. When a teacher decides that a student won’t learn, that student is prevented from learning.
And researchers have developed an automated image analysis that predicts the likelihood that someone is a criminal just from a photograph of his clean-shaven face. Which isn’t as evil as it sounds. Or, rather, it is evil, but not because a computer is doing it – the computer algorithm is simply revealing and quantifying the evil way we humans judge people by their appearances.
Genetics differences are real, and they do make a substantial contribution to people’s proclivities. But human brains are so plastic that the way we’re treated matters more: if you’re curious, you might want to check out this inadvertent identical twin study.
With a glance, we form strong opinions about people’s characters. Some children we brand “pre-criminals.” Is it shocking that, after decades of mistreatment and scrutiny, these children become the lawbreakers we always expected them to be?