Confirmation bias, or different priors?

Consider two people.

Person A is a person of color who grew up in an upper middle class household in a wealthy and crime-free neighborhood. This person has gone through their life encountering mostly others similar to themselves – well-educated liberals that believe strongly in socially progressive ideals. They would deny ever having personally experienced or witnessed racism, despite their skin color. In addition, when their friends discuss the problem of racism in America, they feels a baseline level of skepticism about the actual extent of the problem, and suspect that the whole thing has been overblown by sensationalism in the media. Certainly there was racism in the past, they reason, but the problem seems largely solved in the present day. This suspicion of the mainstream narrative seems confirmed by the emphasis placed on shootings of young black men like Michael Brown, which were upon closer reflection not clear cases of racial discrimination at all.

Person B grew up in a lower middle class family, and developed friendships across a wide range of socioeconomic backgrounds. They began witnessing racist behavior towards black friends at a young age. As they got older, this racism became more pernicious, and several close friends described their frustration at experiences of racial profiling. Many ended up struggling with the law, and some ended up in jail. Studying history, they could see that racism is not a new phenomenon, and descends from a long and brutal history of segregation, Jim Crow, and discriminatory housing practices. To Person B, it is extremely obvious that racism is a deeply pervasive force in society today, and that it results in many injustices. These injustices are those that sparked the Black Lives Matter movement, which they are an enthusiastic supporter of. They are aware that BLM has made some mistakes in the past, but they see a torrent of evidence in favor of the primary message of the movement: that policing is racially biased.

Now both A and B are presented with the infamous Roland Fryer study finding that when you carefully control for confounding factors, black people are no more likely to be shot by police officers than whites, and are in fact slightly less likely to be shot than whites.

Person A is not super surprised by these results, and feels vindicated in his skepticism of the mainstream narrative. To them, this is clear-cut evidence supporting their preconception that a large part of the Black Lives Matter movement rests on an exaggeration of the seriousness of racial issues in the country.

On the other hand, Person B right away dismisses the results of this study. They know from their whole life experience that the results must be flawed, and their primary take-away is the fallibility of statistics in analyzing complex social issues.

They examine the study closely, trying to find the flaw. They come up with a few hypotheses: (1) The data is subject to one or more selection biases, having been provided by police departments that have an interest in seeming colorblind, and having come from the post-Ferguson period in which police officers became temporarily more careful to not shoot blacks (dubbed the Ferguson effect). (2) The study looked at encounters between officers and blacks/whites, but didn’t take into account the effects of differential encounter rates. If police are more likely to pull over or arrest black people than white people for minor violations, then this would artificially lower the rate of officer shootings.

A and B now discuss the findings. Witnessing B’s response to the data, A perceives it as highly irrational. It appears to be a textbook example of confirmation bias. B immediately dismissed the data that contradicted their beliefs, and rationalized it by conjuring complicated explanations for why the results of the study were wrong. Sure, (thinks Person A) these explanations were clever and suggested the need for more nuance in the statistical analysis, but clearly it was more likely that the straightforward interpretation of the data was correct than these complicated alternatives.

B finds A’s quick acceptance of the results troubling and suggestive of a lack of nuance. To B, it appears that A already had their mind made up, and eagerly jumped onto this study without being sufficiently cautious.

Now the two are presented with a series of in-depth case studies of shootings of young black men that show clear evidence of racial profiling.

These stories fit perfectly within B’s worldview, and they find themselves deeply moved by the injustices that these young men experienced. Their dedication to the cause of fighting police brutality is reinvigorated.

But now A is the skeptical one. After all, the plural of anecdote is not data, and the existence of some racist cops by no means indicts all of society as racist. And what about all the similar stories with white victims that don’t get reported? They also recall the pernicious effects of cognitive biases that could make a young black man fed narratives of police racism more likely to see racism where there is none.

To B, all of this gives them the impression that A is doing cartwheels to avoid acknowledging the simple fact that racism exists.

In the first case, was Person B falling prey to confirmation bias? Was A? Were they both?

How about in the second case… Is A thinking irrationally, as B believes?

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I think that in both cases, the right answer is most likely no. In each case we had two people that were rationally responding to the evidence that they received, just starting from very different presuppositions.

Said differently, A and B had vastly different priors upon encountering the same data, and this difference is sufficient to explain their differing reactions. Given these priors it makes sense and is perfectly rational for B to quickly dismiss the Fryer report and search for alternative explanations, and for A to regard stories of racial profiling as overblown. It makes sense for the same reason that it makes sense for a scientist encountering a psychic that seems eerily accurate to right away write it off as some complicated psychological illusion… strong priors are not easily budged by evidence, and there are almost always alternative explanations that are more likely.

This is all perfectly Bayesian, by the way. If two interpretations of a data set equally well predict or make sense of the data (i.e. P(data | interpretation 1) = P(data | interpretation 2)), then their posterior odds ratio P(interpretation 1 | data) / P(interpretation 2 | data) should be no different from their prior ratio P(interpretation 1) / P(interpretation 2). In other words, strong priors dictate strong posteriors when the evidence is weakly discriminatory between the hypotheses.

When the evidence does rule out some interpretations, probability mass is preferentially shifted towards the interpretations that started with stronger priors. For instance, suppose you have three theories with credences (P(T1), P(T2), P(T3)) = (5%, 5%, 90%), and some evidence E is received that rules out T1, but is equally likely under T2 and T3. Then your posterior probabilities will be (P(T1 | E), P(T2 | E), P(T3 | E)) = (0%, 5.6%, 94.4%).

T2 gains only .6% credence, while T3 gains 4.4%. In other words, while the posterior odds stay the same, the actual probability mass has shifted relatively more towards theories favored in the prior.

The moral of this story is to be careful when accusing others, internally or externally, of confirmation bias. What looks like mulish unwillingness to take seriously alternative hypotheses can actually be good rational behavior and the effect of different priors. Being able to tell the difference between confirmation bias and strong priors is a hard task – one that most people probably won’t undertake, opting instead to assume the worst of their ideological opponents.

Another moral is that privilege is an important epistemic concept. Privilege means, in part, having lived a life sufficiently insulated from injustice that it makes sense to wonder if it is there at all. Privilege is a set of priors tilted in favor of colorblindness and absolute moral progress. “Recognizing privilege” corresponds to doing anthropic reasoning to correct for selection biases in the things you have personally experienced, and adjusting your priors accordingly.

A shameful history

Perhaps there has been, at some point in history, some great power whose elevation was exempt from the violent exploitation of other human bodies. If there has been, I have yet to discover it. But this banality of violence can never excuse America, because America makes no claim to the banal. America believes itself exceptional, the greatest and noblest nation ever to exist, a lone champion standing between the white city of democracy and the terrorists, despots, barbarians, and other enemies of civilization. One cannot, at once, claim to be superhuman and then plead moral error. I propose to take our countrymen’s claims of American exceptionalism seriously, which is to say I propose subjecting our country to an exceptional moral standard. This is difficult because there exists, all around us, an apparatus urging us to accept American innocence at face value and not to inquire too much. And it is so easy to look away, to live with the fruits of our history and to ignore the great evil done in all of our names. But you and I have never truly had that luxury.

Ta-Nehisi Coates, Between The World And Me

I’ve had a bit of a revolution in my thinking recently. This revolution has consisted of becoming properly acquainted with the horror that is American history.

I am not the type of writer that can inspire emotion with the type of eloquence in the above quote. But it feels atrocious to me that the true nature of American history, which should be appreciated by every American, is not taught in schools, or is taught in a softened and white-washed form. I would like to share a few facts about the history of my country that I wish I had known earlier.

Legal Racism

Naturalization and whiteness

  • From the very beginning of our country’s history, Congress explicitly stated that only white immigrants could become citizens.
  • This stayed in place for over 100 years. In 1922 (Ozawa v. US), a Japanese-American man who had lived in the United States for 20 years was ruled ineligible for naturalization by the US Supreme Court.
  • From the decision: “In all of the naturalization acts from 1790 to 1906 the privilege of naturalization was confined to white persons.” This was used to conclude that Japanese could not be naturalized.
  • In both this case and a subsequent case (US v. Bhagat Singh Thind, 1923), the US Supreme Court specifically ruled that Japanese and Indian people do not count as white, and thus are racially ineligible for naturalized citizenship.
  • Bhagat Singh argued for his status as a white person by pointing to his Brahmin status. He argued that his people were originally the conquerers of the indigenous population of India, thus giving them an equal claim to whiteness.
  • Arguments from Bhagat Singh’s lawyers: Singh had a revulsion to marrying Indian women from the “lower races,” and had expressed a “disdain for inferiors” that characterized him as white.
    • “The high-caste Hindu regards the aboriginal Indian Mongoloid in the same manner as the American regards the Negro, speaking from a matrimonial standpoint.”
  • The court decided against the whiteness of high-caste Indians, because “while the invaders seem to have met with more success in the effort to preserve their racial purity, intermarriages did occur producing an intermingling of the two and destroying to a greater or less degree the purity of the “Aryan” blood.”
  • An irony: the Statue of Liberty was dedicated in 1886 with the famous quote…

    “Give me your tired, your poor, Your huddled masses yearning to breathe free, The wretched refuse of your teeming shore. Send these, the homeless, tempest-tossed, to me: I lift my lamp beside the golden door.”

    … At this time, only whites had naturalization rights, and the Chinese Exclusion Act had restricted all Chinese immigration to the country four years before.

Oriental exclusion

  • The Chinese Exclusion Act was passed in 1882, banning Chinese immigration for ten years.
  • In 1892 it was extended for another ten years, with the additions that that all Chinese residents must carry permits, that they could not serve as witnesses in court, and that they weren’t allowed bail.
  • In 1902, it was again renewed, this time with no ending date.
  • In 1913, California prohibited Chinese and Japanese immigrants from owning property. Other states followed suit.
  • In 1922, the Cable Act ruled that if an American woman married an Asian, she would lose her citizenship.
  • In 1924, the Oriental Exclusion Act prohibited most immigration from Asia, including foreign-born wives and children of American citizens of Chinese ancestry.
  • In 1929, the National Origins Formula completely barred Asian immigration.
  • In 1952, all federal anti-Asian exclusion laws are finally nullified by the Walter-McCarran Act, allowing for the naturalization of all Asians.

Interracial marriage

  • Laws banning interracial marriage (i.e. marriage between whites and non-whites) were enforced in many states up until 1967… a mere fifty years ago.
  • At least three constitutional amendments banning interracial marriage were introduced in Congress.
  • Quote from a speech given before Congress by a Georgian governor in 1912:
    • No brutality, no infamy, no degradation in all the years of southern slavery, possessed such villainous character and such atrocious qualities as the provision of the laws of Illinois, Massachusetts, and other states which allow the marriage of the negro, Jack Johnson, to a woman of Caucasian strain. [applause]. Gentleman, I offer this resolution … that the States of the Union may have an opportunity to ratify it. …

      Intermarriage between whites and blacks is repulsive and averse to every sentiment of pure American spirit. It is abhorrent and repugnant to the very principles of Saxon government. It is subversive of social peace. It is destructive of moral supremacy, and ultimately this slavery of white women to black beasts will bring this nation a conflict as fatal as ever reddened the soil of Virginia or crimsoned the mountain paths of Pennsylvania.

      … Let us uproot and exterminate now this debasing, ultra-demoralizing, un-American and inhuman leprosy.

  • Anti-miscegenation laws were deemed constitutional by the US Supreme Court in 1883. The argument was that both races were treated equally, “because whites and blacks were punished in equal measure for breaking the law against interracial marriage and interracial sex.”
  • Idaho banned interracial marriage and sex between black and white people in 1921, even though the state’s population was 99.8% non-black.
  • In 1967, the Supreme Court finally ruled these laws (that were enforced in 17 Southern states – all the former slave states) unconstitutional.
  • It took South Carolina until 1998 and Alabama until 2000 to actually remove the ban on interracial marriage from their Constitutions.
    • In the respective referendums, 38% of voters in South Carolina and 41% of voters in Alabama voted to keep the ban in place.

Racism now

  • A 2018 study found that Republican-appointed judges sentence blacks to 3 more months than similar non-blacks. This is 65% of the baseline racial sentence gap.
    • “These differences cannot be explained by other judge characteristics and grow substantially larger when judges are granted more discretion.”
  • A 2011 poll of Mississippi Republicans found that 46% think interracial marriage should be illegal, and 14 percent replied “not sure.”
  • A 2007 Gallup poll found that 17% of Americans explicitly disapprove of interracial marriage.
  • Black job applicants without criminal records have the same chance of getting hired as white applicants with criminal records.
  • If current trends continue, one of every three black American males born today can expect to go to prison in his lifetime.

 

There is so much more, and I haven’t even touched the brutality of the branch of US law dedicated to stripping Native Americans of their homes and their lives. Taking into account this disturbing legacy of white supremacy, one wonders how a slogan like “Make America Great Again” could be anything but a dog-whistle for the type of bigotry and hatred that has always been our nation’s past. It also casts the notion of American pride in an ominous light. The only attitude I can summon up thinking about the realities of our country’s past is shame. Is “proud to be an American” a sentiment borne of ignorance, or something more sinister?

 

You must struggle to truly remember this past in all its nuance, error, and humanity. You must resist the common urge toward the comforting narrative of divine law, toward fairy tales that imply some irrepressible justice. The enslaved were not bricks in your road, and their lives were not chapters in your redemptive history. They were people turned to fuel for the American machine…

Our triumphs can never compensate for this. Perhaps our triumphs are not even the point. Perhaps struggle is all we have because the god of history is an atheist, and nothing about this world is meant to be. So you must wake up every morning knowing that no promise is unbreakable, least of all the promise of waking up at all. This is not despair. These are the preferences of the universe itself: verbs over nouns, actions over states, struggle over hope.

Ta-Nehisi Coates, Between The World And Me

“Beating the drum for justice”

I’m going to quote a few pages from Just Mercy by Bryan Stevenson here, because I think they’re really important. It’s pretty crazy how no matter how many times I read them, a little lump in my throat never fails to develop.

I want to let the quote sit by itself without added commentary, so let me just say that I think this is a book that every person should read.

After making the three-hour drive back from Gadsden earlier in the day and heading straight to the office, it was once again approaching midnight as I left the office for home. I got in my car, and to my delight the radio came on as soon as I turned the ignition. In just over three years of law practice I had become one of those people for whom such small events could make a big difference in my joy quotient. On this late night, not only was my radio working but the station was also hosting a retrospective on the music of Sly and the Family Stone. I’d grown up listening to Sly and found myself rolling joyfully through the streets of Atlanta to tunes like “Dance to the Music,” “Everybody Is a Star,” and “Family Affair.”

Our Midtown Atlanta apartment was on a dense residential street. Some nights I had to park halfway down the block or even around the corner to find a space. But tonight I was lucky: I parked my rattling Civic just steps from our new front door just as Sly was starting “Hot Fun in the Summertime.” It was late, and I needed to get to bed, but the moment was too good to let pass, so I remained in the car listening to the music. Each time a tune ended I told myself to go inside, but then another irresistible song would begin, and I would find myself unable to leave. I was singing along to “Stand!” the soaring Sly anthem with the great gospel-themed ending, when I saw a flashing police light approaching. I was parked a few doors up from our apartment, so I assumed that the officers would drive by in pursuit of some urgent mission. When they came to a stop twenty feet in front of me, I wondered what was going on.

Our section of the street only ran one way. My parked car was facing in the proper direction; the police car had come down the street in the wrong direction. I noticed for the first time that it wasn’t an ordinary police cruiser but one of the special Atlanta SWAT cars. The officers had a spotlight attached to their vehicle, and they directed it at me sitting in my car. Only then did it occur to me that they might be there for me, but I couldn’t imagine why. I had been parked on the street for about fifteen minutes listening to Sly. Only one of my car speakers worked and not very well. I knew the music couldn’t be heard outside the car.

The officers sat there with their light pointed at me for a minute or so. I turned off the radio before “Stand!” was over. I had case files on my car seat about Lourida Ruffin and the young man who had been shot in Gadsden. Eventually two police officers got out of their vehicle. I noticed immediately that they weren’t wearing the standard Atlanta police uniform. Instead they were ominously dressed in military style, black boots with black pants and vests.

I decided to get out of my car and go home. Even though they were intensely staring at me in my car, I was still hoping that they were in the area for something unrelated to me. Or if they were concerned that something was wrong with me, I figured I would let them know that everything was okay. It certainly never occurred to me that getting out of my car was wrong or dangerous.

As soon as I opened my car door and got out, the police officer who had started walking toward my vehicle drew his weapon and pointed it at me. I must have looked completely bewildered.

My first instinct was to run. I quickly decided that wouldn’t be smart. Then I thought for an instant that maybe these weren’t real police officers.

“Move and I’ll blow your head off!” The officer shouted the words, but I couldn’t make any sense of what he meant. I tried to stay calm; it was the first time in my life anyone had ever pointed a gun at me.

“Put your hands up!” The officer was a white man about my height. In the darkness I could only make out his black uniform and his pointed weapon.

I put my hands up and noticed that he seemed nervous. I don’t remember deciding to speak, I just remember the words coming out: “It’s all right. It’s okay.”

I’m sure I sounded afraid because I was terrified.

I kept saying the words over and over again. “It’s okay, it’s okay.” Finally I said, “I live here, this is my apartment.”

I looked at the officer who was pointing the gun at my head less than fifteen feet away. I thought I saw his hands shaking.

I kept saying as calmly as I could: “It’s okay, it’s okay.”

The second officer, who had not drawn his weapon, inched cautiously toward me. He stepped on the sidewalk, circled behind my parked car, and came up behind me while the other officer continued to point the gun at me. He grabbed me by the arms and pushed me up against the back of my car. The other officer then lowered his weapon.

“What are you doing out here?” said the second officer, who seemed older than the one who had drawn his weapon. He sounded angry.

“I live here. I moved into that house down the street just a few months ago. My roommate is inside. You can go ask him.” I hated how afraid I sounded and the way my voice was shaking.

“What are you doing out in the street?”

“I was just listening to the radio.” He placed my hands on the car and bent me over the back of the vehicle. The SWAT car’s bright spotlight was still focused on me. I noticed people up the block turning on their lights and peering out of their front doors. The house next to ours came to life, and a middle-aged white man and woman walked outside and stared at me as I was leaned over the vehicle.

The officer holding me asked me for my driver’s license but wouldn’t let me move my arms to retrieve it. I told him that it was in my back pocket, and he fished my wallet out from my pants. The other officer was now leaning inside my car and going through my papers. I knew that he had no probable cause to enter my vehicle and that he was conducting an illegal search. I was about to say something when I saw him open the glove compartment. Opening objects in a parked vehicle was so incredibly illegal that I realized he wasn’t paying any attention to the rules, so saying something about it would be pointless.

There was nothing interesting in my car. There were no drugs, no alcohol, not even tobacco. I kept a giant-size bag of peanut M&Ms and Bazooka bubble gum in the glove compartment to help stave off hunger when I didn’t have time for a meal. There were just a few M&Ms left in the bag, which the officer inspected carefully. He put his nose into the bag before tossing it back. I wouldn’t be eating those M&Ms.

I had not lived at our new address long enough to get a new driver’s license, so the address on my license didn’t match the new location. There was no legal requirement to update the driver’s license, but it prompted the officer to hold me there for another ten minutes while he went back to his car to run a search on me. My neighbors grew bolder as the encounter dragged on. Even though it was late, people were coming out of their homes to watch. I could hear them talking about all the burglaries in the neighborhood. There was a particularly vocal older white woman who loudly demanded that I be questioned about items she was missing.

“Ask him about my radio and my vacuum cleaner!” Another lady asked about her cat who had been absent for three days. I kept waiting for my apartment light to come on and for Charlie to walk outside and help me out. He had been dating a woman who also worked at Legal Aid and had been spending a lot of time at her house. It occurred to me that he might not be home.

Finally, the officer returned and spoke to his partner: “They don’t have anything on him.” He sounded disappointed.

I found my nerve and took my hands off the car. “This is so messed up. I live here. You shouldn’t have done this. Why did you do this?”

The older officer frowned at me. “Someone called about a suspected burglar. There have been a lot of burglaries in this neighborhood.” Then he grinned. “We’re going to let you go. You should be happy,” he said.

With that, they walked away, got in their SWAT car, and drove off. The neighbors looked me over one last time before retreating back into their homes. I couldn’t decide whether I should race to my door so that they could see that I lived in the neighborhood or wait until they were all gone so that no one would know where the “suspected criminal” lived. I decided to wait.
I gathered up my papers, which the cop had scattered all over the car and onto the sidewalk. I unhappily threw my M&Ms into a trash can on the street and then walked into my apartment. To my great relief, Charlie was there. I woke him to tell the story.

“They never even apologized,” I kept saying. Charlie shared my outrage but soon fell back asleep. I couldn’t sleep at all.

The next morning I told Steve about the incident. He was furious and urged me to file a complaint with the Atlanta Police Department. Some folks in the office said I should explain in my complaint that I was a civil rights attorney working on police misconduct cases. It seemed to me that no one should need those kinds of credentials to complain about misconduct by police officers.

I started writing my complaint determined not to reveal that I was an attorney. When I replayed the whole incident in my mind, what bothered me most was the moment when the officer drew his weapon and I thought about running. I was a twenty-eight-year-old lawyer who had worked on police misconduct cases. I had the judgment to speak calmly to the officer when he threatened to shoot me. When I thought about what I would have done when I was sixteen years old or nineteen or even twenty-four, I was scared to realize that I might have run. The more I thought about it, the more concerned I became about all the young black boys and men in that neighborhood. Did they know not to run? Did they know to stay calm and say, “It’s okay”?

I detailed all of my concerns. I found Bureau of Justice statistics reporting that black men were eight times more likely to be killed by the police than whites. By the end of the twentieth century the rate of police shootings would improve so that men of color were “only” four times more likely to be killed by law enforcement, but the problem would get worse as some states passed “Stand Your Ground” laws empowering armed citizens to use lethal force as well.

I kept writing my memo to the Atlanta Police Department and before I knew it I had typed close to nine pages outlining all the things I thought had gone wrong. For two pages I detailed the completely illegal search of the vehicle and the absence of probable cause. I even cited about a half-dozen cases. I read over the complaint and realized that I had done everything but say, “I’m a lawyer.”

I filed my complaint with the police department and tried to forget about the incident, but I couldn’t. I kept thinking about what had happened. I began to feel embarrassed that I hadn’t asserted more control during the encounter. I hadn’t told the officers I was a lawyer or informed them that what they were doing was illegal. Should I have said more to them? Despite the work I’d done assisting people on death row, I questioned how prepared I was to do really difficult things. I even started having second thoughts about going to Alabama to start a law office. I couldn’t stop thinking about how at risk young kids are when they get stopped by the police.

My complaint made it through the review process at the Atlanta Police Department. Every few weeks I’d get a letter explaining that the police officers had done nothing wrong and that police work is very difficult. I appealed these dismissals unsuccessfully up the chain of command. Finally, I requested a meeting with the chief of police and the police officers who had stopped me. This request was denied, but the deputy chief met with me. I had asked for an apology and suggested training to prevent similar incidents. The deputy chief nodded politely as I explained what had happened. When I finished, he apologized to me, but I suspected that he just wanted me to leave. He promised that the officers would be required to do some “extra homework on community relations.” I didn’t feel vindicated.

My caseload was getting crazy. The lawyers defending the Gadsden City Jail finally acknowledged that Mr. Ruffin’s rights had been violated and that he had been illegally denied his asthma medicine. We won a decent settlement for Mr. Ruffin’s family, so they would at least receive some financial help. I turned the other police misconduct cases over to other lawyers because my death penalty docket was so full.

I had no time to make war with the Atlanta Police when I had clients facing execution. Still, I couldn’t stop thinking about how dangerous and unfair the situation was and how I’d done nothing wrong. And what if I had had drugs in my car? I would have been arrested and then would have needed to convince my attorney to believe me when I explained that the police had entered the car illegally. Would I get an attorney who would take such a claim seriously? Would a judge believe that I’d done nothing wrong? Would they believe someone who was just like me but happened not to be a lawyer? Someone like me who was unemployed or had a prior criminal record?
I decided to talk to youth groups, churches, and community organizations about the challenges posed by the presumption of guilt assigned to the poor and people of color. I spoke at local meetings and tried to sensitize people to the need to insist on accountability from law enforcement. I argued that police could improve public safety without abusing people. Even when I was in Alabama, I made time for talks at community events whenever anyone asked.

I was in a poor rural county in Alabama after another trip to pull records in a death penalty case when I was invited to speak at a small African American church. Only about two dozen people showed up. One of the community leaders introduced me, and I went to the front of the church and began my talk about the death penalty, increasing incarceration rates, abuse of power within prisons, discriminatory law enforcement, and the need for reform. At one point, I decided to talk about my encounter with the police in Atlanta, and I realized that I was getting a bit emotional. My voice got shaky, and I had to rein myself in to finish my remarks.

During the talk, I noticed an older black man in a wheelchair who had come in just before the program started. He was in his seventies and was wearing an old brown suit. His gray hair was cut short with unruly tufts here and there. He looked at me intensely throughout my presentation but showed no emotion or reaction during most of the talk. His focused stare was unnerving. A young boy who was about twelve had wheeled him into the church, probably his grandson or a relative. I noticed that the man occasionally directed the boy to fetch things for him. He would wordlessly nod his head, and the boy seemed to know that the man wanted a fan or a hymnal.

After I finished speaking, the group sang a hymn to end the session. The older man didn’t sing but simply closed his eyes and sat back in his chair. After the program, people came up to me; most folks were very kind and expressed appreciation for my having taken the time to come and talk to them. Several young black boys walked up to shake my hand. I was pleased that people seemed to value the information I shared. The man in the wheelchair was waiting in the back of the church. He was still staring at me. When everyone else had left, he nodded to the young boy, who quickly wheeled him up to me.

The man’s expression never changed as he approached me. He stopped in front of me, leaned forward in his wheelchair, and said forcefully, “Do you know what you’re doing?” He looked very serious, and he wasn’t smiling.

His question threw me. I couldn’t tell what he was really asking or whether he was being hostile. I didn’t know what to say. He then wagged his finger at me, and asked again. “Do you know what you’re doing?”

I tried to smile to diffuse the situation but I was completely baffled. “I think so.…”

He cut me off and said loudly, “I’ll tell you what you’re doing. You’re beating the drum for justice!” He had an impassioned look on his face. He said it again emphatically, “You’ve got to beat the drum for justice.”

He leaned back in his chair, and I stopped smiling. Something about what he said had sobered me. I answered him softly, “Yes, sir.”

He leaned forward again and said hoarsely, “You’ve got to keep beating the drum for justice.” He gestured and after a long while said again, “Beat the drum for justice.”

He leaned back, and in an instant he seemed tired and out of breath. He looked at me sympathetically and waved me closer. I did so, and he pulled me by the arm and leaned forward. He spoke very quietly, almost a whisper, but with a fierceness that was unforgettable.

“You see this scar on the top of my head?” He tilted his head to show me. “I got that scar in Greene County, Alabama, trying to register to vote in 1964. You see this scar on the side of my head?” He turned his head to the left and I saw a four-inch scar just above his right ear. “I got that scar in Mississippi demanding civil rights.”

His voice grew stronger. He tightened his grip on my arm and lowered his head some more. “You see that mark?” There was a dark circle at the base of his skull. “I got that bruise in Birmingham after the Children’s Crusade.”

He leaned back and looked at me intensely. “People think these are my scars, cuts, and bruises.”

For the first time I noticed that his eyes were wet with tears. He placed his hands on his head. These aren’t my scars, cuts, and bruises. These are my medals of honor.”

He stared at me for a long moment, wiped his eyes, and nodded to the boy, who wheeled him away.

I stood there with a lump in my throat, staring after him.

After a moment, I realized that the time to open the Alabama office had come.

Bryan Stevenson, Just Mercy

Against the status quo

A good analysis of our society involves, I think, the ability to look at everything from the perspective of an alien – to remove ourselves from the contingent fact of our place in history and negate the biases and blind spots that might result from it.

If you were to be dropped out of a time machine into pretty much any time in American history, you would see enormous injustices happening everywhere, as well as status quo that is either blind or apathetic towards these injustices.

Social progress is so sudden and final that it’s easy to lose track of this truth. Women have only had the right to vote for the last 100 years, and the first woman to be admitted to Harvard Law School was in 1950. I’m very confident that it will never again be the case that women will not be legally allowed to vote in the United States, or banned from institutions of higher learning. We’ve moved as a society in a direction that we are never coming back from.

Racial discrimination in voting was only technically prohibited after 1965. Just fifty to sixty years ago in the United States, we have elected officials who rose to power by proudly preaching Jim Crow and segregation, affiliating with the Ku Klux Klan, and boasting about chasing black people out of their restaurants with ax handles. Lynching was a common practice in the United States for hundreds of years; Emmett Till was brutally tortured to death for wolf-whistling a white woman in 1955. Professional photographs of lynchings were published as postcards, to be sold as popular souvenirs. Etc etc.

The point of all of this is just to say that it looks like we should have a really strong presumption in favor of there being current massive flaws in the status quo. The argument being: at basically any point in history, the status quo has been blind towards and accept of stunning levels of injustice. While the trend of history has been towards progress and a widening moral circle, we should still suspect that there are aspects of society today that are massively unjust unless we think that we are in an incredibly unique historical moment. We should also suspect that we are vulnerable to the same biases that people have always historically been blind to in failing to see basic moral failings of the society in which they exist.

This raises the question: What are the massive injustices going on today? Where are our blind spots? 100 years down the line, what will people read about us that will make them wonder how we sat by and didn’t do anything?

This is a really hard question, and I only have a few answers that I’m pretty confident about. One of these is animal rights issues. We are inflicting enormous degrees of needless cruelty on animals, and I get the sense that the average American’s attitude towards this is essentially total apathy (although there has been a definite change in this attitude in recent years). Another possibility is mass incarceration. The US has the highest incarceration rate in the world, and we lock crazy amounts of people up for victimless crimes. Time in prison is brutally unpleasant, and for those that act out, solitary confinement is the punishment.

What other things do we accept in modern society that our descendants will look back on and hang their heads in shame about?

Some social justice factoids

Starting on a brief personal note…

I’m a bit disappointed with myself for being absent from this blog for the past few weeks. In a Reddit AMA last week, my favorite blogger said that the limiting factor on his productivity is the amount of time he has in a day. This to me is an ideal that I wish I could always be at. The limiting factor on my productivity is almost always my mental capacity to avoid the infinite potential sources of short-term gratification, and to motivate myself to do the things that I get deeper and more long-lived satisfaction out of. Writing this blog is one of those things. My capacity to enforce mental discipline is pretty correlated with my overall state of mind and mood. I think you can actually probably fairly reliably track my mental health by just looking at how often I’m posting here!

I’m also disappointed because I have been thinking about a great many interesting things that deserve posts. I like the idea of using this blog as a faithful recording of my intellectual life, and having discontinuities doesn’t help with this. Much of what I’ve been thinking about over the past few weeks is related to meta-ethics, but it also goes more broadly into the nature of philosophy in general. I hope to write up some posts on these soon.

In the meantime, I’ve also been compiling some interesting factoids I’ve recently encountered related to social justice. Here they are, with sources!

Race

  • Bias against blacks in the justice system can be found in sentencing and in arrests for drug use, but not in arrest rates for violent crimes, police shootings, prosecution rates, or conviction rates. Source.
  • Juries in the Deep South were commonly all-white up until the 1986 case Batson v Kentucky (where loopholes that allowed exclusion of blacks from juries were closed). (from Just Mercy, p. 60)
  • Black Americans graduate from high school at the same rate as white Americans (92.3% vs 95.6%). Source.
    • In 1968, these numbers were 54.4% and 75%.
    • Percentage of college graduates age 25 to 29: 22.8% and 42.1%. (19.3% gap)
  • White adults who don’t graduate high school, don’t get married before having children, and don’t work full time have much greater median wealth than comparable black and Latino adults. Source.
    • Consumption habits can’t explain the wealth gap: white households spend more than black households of comparable incomes.
    • The median white single parent has 2.2 times more wealth than the median black two-parent household and 1.9 times more wealth than the median Latino two-parent household.
  • Poverty rates among African Americans have declined substantially: 34.7% in 1968 to 21.4% in 2016. Source.
    • Among whites: 10% in 1968 to 8.8% in 2016.
  • Great table showing the change in socioeconomic circumstances of blacks and whites in the US from 1968 to 2018: (Source)  
    • Most strikingly in that table… Median household wealth is 10 times higher for white Americans than black Americans (but it used to be 20 times higher).

Gender

  • There is a 7% unexplained wage gap between men and women in the US. Source.
    • Controlling for college major selection, occupational segregation, hours worked, unionization, education, race, ethnicity, age, and marital status.
  • Female leaders are evaluated slightly more negatively than equivalent male leaders (controlling for leadership style). Source.
    • The discrepancy is more pronounced for autocratic leadership styles, and vanishes for democratic leadership styles.
  • Most anthropologists hold there are no known societies that are/were unambiguously matriarchal. Source.
  • Experiments show that women value temporal flexibility relatively more than men, and men value income growth relatively more than women. This is the most powerful explanation of the wage gap. Source.
    • Right after college, wages are pretty similar between men and women, and the wage gap appears as time passes, indicating that ‘innate’ differences aren’t hugely at play (including bargaining ability and temperament).
    • 75% of the wage gap is due to differences within occupations, and only 25% across occupations.
    • Among the top-paying occupations (salary ≥ $60K), the within-occupation corrected pay gaps are biggest where there’s lots of self-employment (explained by self-employment being more demanding).
  • Symphony orchestras introduced blind auditions in the ‘90s, which served as a natural experiment that found significant gender bias against women. Source.
    • The analysis found that in a blind audition for preliminary rounds, the same woman was 9.3% more likely to be hired (from 19.3% to 28.6%), and the same man is 2.3% less likely to be hired.
    • For final rounds, the same woman was 14.8% more likely to be hired in a blind audition (from 8.7% to 23.5%).
    • Introduction of blind auditions also caused an explosion of female auditions.
  • The rate of false reporting for sexual assault is in the range of 2-8%. Source.
  • Estimates of the prevalence rate of campus sexual assault in the US vary hugely, from .61% to 27% of female students, depending on survey definitions and methodology. Source.
  • The percentage of trans men that report lifetime suicide attempts is 46%, trans women is 42%, LGB adults is 10-20%, and among the overall US population is 4.6%. Source.
    • Suicide attempt rates are lower (by about 9%) among trans women that are perceived by others as women, but are the same among trans men.

Other

  • “The IAT is a noisy, unreliable measure that correlates far too weakly with any real-world outcomes to be used to predict individuals’ behavior.” Source.
    • Many early studies on IAT as a predictor of discriminatory behavior had serious methodological problems, including falsification of data by an “overzealous undergraduate”.
    • IAT has a test-retest reliability of .55 on a scale from 0 to 1.
    • Meta-analyses of the IAT-behavior link show that race IAT scores are weak predictors of discriminatory behavior.
    • IAT tests done on fictional races that are identified as one oppressed and the other privileged show “implicit bias” against the oppressed group.
    • More noise in the data predictably biases the IAT score downwards
  • When people hear stereotyping is normal, they may do more of it. Source.
  • The “few antibias trainings that have been proven to change people’s behavior” look at bias as a habit that can be broken. The Prejudice and Intergroup relations lab at UW Madison has had promising results with these type of trainings. Source.

Some takeaways: A lot of the concerns of the social justice movement are clearly very valid and rooted in real issues of societal inequalities that have been handed down to us by previous generations. That said, however, there is a good degree of subtlety required in the analysis of race and gender issues that is missing in the mainstream social justice movement.

The oft-cited 23% gender gap is misleading to say the least, and the actual percentage due to discrimination is unclear but something less than 7%. The focus the Black Lives Matter movement puts on racially biased police shootings is unjustified, and the focus would be better placed on disparate sentencing and drug arrests. And more generally, the overall trends in racial inequality in the United States look extremely positive in virtually every dimension.

It also looks like current methods at identifying and intervening on things like implicit bias and stereotyping leave a lot to be desired. This has some serious implications for questions about actual practical solutions to issues of racism and sexism… even if we acknowledge their existence and seriousness, this does not mean that we should jump on board with any plausible-sounding diversity training program. The question of how to solve these issues is highly nontrivial and deserves a lot of careful attention.

Defining racism

How would you define racism?

I’ve been thinking about this lately in light of some of the scandal around research into race and IQ. It’s a harder question than I initially thought; many of the definitions that pop to mind end up being either too strong or too weak. The term also functions differently in different contexts (e.g. personal racism, institutional racism, racist policies). In this post, I’m specifically talking about personal racism – that term we use to refer to the beliefs and attitudes of those like Nazis or Ku Klux Klan members (at the extreme end).

I’m going to walk through a few possible definitions. This will be fairly stream-of-consciousness, so I apologize if it’s not incredibly profound or well-structured.

Definition 1 Racism is the belief in the existence of inherent differences between the races.

‘Inherent’ is important, because we don’t want to say that somebody is racist for acknowledging differences that can ultimately be traced back to causes like societal oppression. The problem with this definition is that, well, there are inherent differences between the races.

The Chinese are significantly shorter than the Dutch. Raising a Chinese person in a Dutch household won’t do much to equalize this difference. What’s important, it seems, is not the belief in the existence of inherent differences, but instead the belief in the existence of inherent inferiorities and superiorities. So let’s try again.

Definition 2 Racism is the belief in the existence of inherent racial differences that are normatively significant.

This is pretty much the dictionary definition of the term “racism”. While it’s better, there are still some serious problems. Let’s say that somebody discovered that the Slavs are more inherently prone to violence than, say, Arabs. Suppose that somebody ran across this fact, and that this person also held the ethical view that violent tendencies are normatively important. That is, they think that peaceful people are ethically superior to violent people.

If they combine this factual belief with this seemingly reasonable normative belief, they’ll end up being branded as a racist, by our second definition. This is clearly undesirable… given that the word ‘racism’ is highly normatively loaded, we don’t want it to be the case that somebody is racist for believing true things. In other words, we probably don’t want our definition of racism to ever allow it to be the right attitude to take, or even a reasonable attitude to take.

Maybe the missing step is the generalization of attitudes about Slavs and Arabs to individuals. This is a sentiment that I’ve heard fairly often… racism is about applying generalizations about groups to individuals (for instance, racial profiling). Let’s formalize this:

Definition 3 Racism is about forming normative judgments about individuals’ characteristics on the basis of beliefs about normative group-level differences.

This sounds nice and all, but… you know what another term for “applying facts about groups to individuals” is? Good statistical reasoning.

If you live in a town composed of two distinct populations, the Hebbeberans and the Klabaskians, and you know that Klabaskians are on average twenty times more likely than Hebbeberans to be fatally allergic to cod, then you should be more cautious with serving your extra special cod sandwich to a Klabaskian friend than to a Hebbeberan.

Facts about populations do give you evidence about individuals within those populations, and the mere acknowledgement of this evidence is not racist, for the same reason that rationality is not racist.

So if we don’t want to call rationality racist, then maybe our way out of this is to identify racism with irrationality.

Definition 4 Racism is the holding of irrational beliefs about normative racial differences.

Say you meet somebody from Malawi (a region with an extremely low average IQ). Your first rational instinct might be to not expect too much from them in the way of cognitive abilities. But now you learn that they’re a theoretical physicist who’s recently been nominated for a Nobel prize for their work in quantum information theory. If the average IQ of Malawians is still factoring in at all to your belief about this person’s intelligence, then you’re being racist.

I like this definition a lot better than our previous ones. It combines the belief in racial superiority with irrationality. On the other hand, it has problems as well. One major issue is that there are plenty of cases of benign irrationality, where somebody is just a bad statistical reasoner, but not motivated by any racial hatred. Maybe they over-updated on some piece of information, because they failed to take into account an important base-rate.

Well, the base-rate fallacy is one of the most common cognitive biases out there. Surely this isn’t enough to make them a racist? What we want is to capture the non-benign brand of irrational normative beliefs about race – those that are motivated by hatred or prejudice.

Definition 5 Racism is the holding of irrational normative beliefs about racial differences, motivated by racial hatred or prejudice.

I think this does the best at avoiding making the category too large, but it may be too strong and keep out some plausible cases of racism. I’d like to hear suggestions for improvements on this definition, but for now I’ll leave it there. One potential take-away is that the word ‘racism’ is a nasty combination of highly negatively charged and ambiguous, and that such words are best treated with caution, especially when applied them to edge cases.

All about IQ

IQ is an increasingly controversial topic these days. I find that when it comes up, different people seem to be extremely confident in wildly different beliefs about the nature of IQ as a measure of intelligence.

Part of this has to do with education. This paper analyzed the top 29 most used introductory psychology textbooks and “found that 79.3% of textbooks contained inaccurate statements and 79.3% had logical fallacies in their sections about intelligence.” [1]

This is pretty insane, and sounds kinda like something you’d hear from an Alex Jones-style conspiracy theorist. But if you look at what the world’s experts on human intelligence say about public opinion on intelligence, they’re all in agreement: misinformation about IQ is everywhere. It’s gotten to the point where world-famous respected psychologists like Steven Pinker are being blasted as racists in articles in mainstream news outlets for citing basic points of consensus in the scientific literature.

The reasons for this are pretty clear… people are worried about nasty social and political implications of true facts about IQ. There are worthwhile points to be made about morally hazardous beliefs and the possibility that some truths should not be publicly known. At the same time, the quantification and study of human intelligence is absurdly important. The difference between us and the rest of the animal world, the types of possible futures that are open to us as a civilization, the ability to understand the structure of the universe and manipulate it to our ends; these are the types of things that the subject of human intelligence touches on. In short, intelligence is how we accomplish anything as a civilization, and the prospect of missing out on ways to reliably intervene and enhance it because we avoided or covered up research that revealed some inconvenient truths seems really bad to me.

Overall, I lean towards thinking that the misinformation is so great, and the truth so important, that it’s worthwhile to attempt to clear things up. So! The purpose of this post is just to sort through some of the mess and come up with a concise and referenced list of some of the most important things we know about IQ and intelligence.

IQ Basics

  • The most replicated finding in all of psychology is that good performance on virtually all cognitively demanding tasks is positively correlated. The name for whatever cognitive faculty causes this correlation is “general intelligence”, or g.
  • A definition of intelligence from 52 prominent intelligence researchers: [2]

Intelligence is a very general capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience. It is not merely book learning, a narrow academic skill, or test‑taking smarts. Rather, it reflects a broader and deeper capability for comprehending our surroundings—‘catching on’, ‘making sense’ of things, or ‘figuring out’ what to do. Intelligence, so defined, can be measured, and intelligence tests measure it well.

  • IQ tests are among the most reliable and valid of all psychological tests and assessments. [3]
    • They are designed to test general intelligence, and not character or personality.
    • Modern IQ tests have a standard error of measurement of about 3 points.
  • The distribution of IQs in a population nicely fits a Bell curve.
    • IQ is defined in such a way as to make the population mean exactly 100, and the standard deviation 15.
  • People with high IQs tend to be healthier, wealthier, live longer, and have more successful careers. [4][5][6]
    • IQ is highly predictive of educational aptitude and job performance. [7][8][9][10][11]
    • Longitudinal studies have shown that IQ “is a causal influence on future achievement measures whereas achievement measures do not substantially influence future IQ scores.” [12]

Average adult combined IQs associated with real-life accomplishments by various tests

Accomplishment IQ
MDs, JDs, and PhDs 125
College Graduates 115
1–3 years of college 104
Clerical and sales workers 100–105
High school graduates, skilled workers (e.g., electricians, cabinetmakers) 97
1–3 years of high school (completed 9–11 years of school) 94
Semi-skilled workers (e.g. truck drivers, factory workers) 90–95
Elementary school graduates (completed eighth grade) 90
Elementary school dropouts (completed 0–7 years of school) 80–85
Have 50/50 chance of reaching high school 75

(table from Wiki)

 

Table 25.1 Relationship between intelligence and measures of success (Results from meta-analyses)
Measure of success r k N Source
Academic performance in primary education 0.58 4 1791 Poropat (2009)
Educational attainment 0.56 59 84828 Strenze (2007)
Job performance (supervisory rating) 0.53 425 32124 Hunter and Hunter (1984)
Occupational attainment 0.43 45 72290 Strenze (2007)
Job performance (work sample) 0.38 36 16480 Roth et al. (2005)
Skill acquisition in work training 0.38 17 6713 Colquitt et al. (2000)
Degree attainment speed in graduate school 0.35 5 1700 Kuncel et al. (2004)
Group leadership success (group productivity) 0.33 14 Judge et al. (2004)
Promotions at work 0.28 9 21290 Schmitt et al. (1984)
Interview success (interviewer rating of applicant) 0.27 40 11317 Berry et al. (2007)
Reading performance among problem children 0.26 8 944 Nelson et al. (2003)
Becoming a leader in group 0.25 65 Judge et al. (2004)
Academic performance in secondary education 0.24 17 12606 Poropat (2009)
Academic performance in tertiary education 0.23 26 17588 Poropat (2009)
Income 0.20 31 58758 Strenze (2007)
Having anorexia nervosa 0.20 16 484 Lopez et al. (2010)
Research productivity in graduate school 0.19 4 314 Kuncel et al. (2004)
Participation in group activities 0.18 36 Mann (1959)
Group leadership success (group member rating) 0.17 64 Judge et al. (2004)
Creativity 0.17 447 Kim (2005)
Popularity among group members 0.10 38 Mann (1959)
Happiness 0.05 19 2546 DeNeve & Cooper (1998)
Procrastination (needless delay of action) 0.03 14 2151 Steel (2007)
Changing jobs 0.01 7 6062 Griffeth et al. (2000)
Physical attractiveness -0.04 31 3497 Feingold (1992)
Recidivism (repeated criminal behavior) -0.07 32 21369 Gendreau et al. (1996)
Number of children -0.11 3 Lynn (1996)
Traffic accident involvement -0.12 10 1020 Arthur et al. (1991)
Conformity to persuasion -0.12 7 Rhodes and Wood (1992)
Communication anxiety -0.13 8 2548 Bourhis and Allen (1992)
Having schizophrenia -0.26 18 Woodberry et al. (2008)

(from Gwern)

Nature of g

  • IQ scores are very stable across lifetime. [13]
    • This doesn’t mean that 30-year-old you is no smarter than 10-year-old you. It means that if you test the IQ of a bunch of children, and then later test them as adults, the rank order will remain roughly the same. A smarter-than-average 10 year old becomes a smarter-than-average 30 year old.
  • After your mid-20s, crystallized intelligence plateaus and  fluid intelligence starts declining. Obligatory terrifying graph: (source)

  • High IQ is correlated with more gray matter in the brain, larger frontal lobes, and a thicker cortex. [14][15]
    • There is a constant cascade of information being processed in the entire brain, but intelligence seems related to an efficient use of relatively few structures, where the more gray matter the better.” [16]
  • “Estimates of how much of the total variance in general intelligence can be attributed to genetic influences range from 30 to 80%.” [17]
    • Twin studies show the same results; there are substantial genetic influences on human intelligence. [18]
    • The genetic component of IQ is highly polygenic, and no specific genes have been robustly associated with human intelligence. The best we’ve found so far is a single gene that accounts for 0.1% of the variance in IQ. [17]
  • Many genes have been weakly associated with IQ. “40% of the variation in crystallized-type intelligence and 51% of the variation in fluid-type intelligence between individuals” is accounted for by genetic differences. [19]
    • Scientists can predict your IQ by looking only at your genes (not perfectly, but significantly better than random). [19]
      • This study analyzed 549,692 base pairs and found a R = .11 mean correlation between their predictions and the actual fluid intelligence of over 3500 unrelated adults. [19]

You might be wondering at this point what all the controversy regarding IQ is about. Why are so many people eager to dismiss IQ as a valid measure of intelligence? Well, we now dive straight into the heart of the controversy: intergroup variation in IQ.

It’s worth noting that, as Scott Alexander puts it: society is fixed, while biology is mutable. This fear we have that if biology factors into the underperformance of some groups, then such difference are intrinsically unalterable, makes little sense. We can do things to modify biology just as we can do things to modify society, and in fact the first is often much easier to do and more effective than the easier.

Anyway, prelude aside, we dive into the controversy.

Group differences in IQ

  • Yes, there are racial differences in IQ, both globally and within the United States. This has been studied to death, and is a universal consensus; you won’t find a single paper in a reputable psychology journal denying the numerical differences. [20]
  • Within the United States, there is a long-standing 1 SD (15 to 18 point) IQ difference between African Americans and White Americans. [2]
    • The tests in which these differences are most pronounced are those that most closely correspond to g, like Raven’s Progressive Matrices. [6] This test also is free of culturally-loaded knowledge, and only requires being able to solve visual pattern-recognition puzzles like these ones:

      • Controlling for the way the tests are formulated and administered does not affect this difference. [2]
      • IQ scores predict success equally accurately regardless of race or social class. This provides some evidence that the test is not culturally biased as a predictor. [2] [19]
  • Internationally, the lowest average IQs are found in sub-Saharan Africa and the highest average IQs are found in East Asia. The variations span a range of three standard deviations (45 IQ points). [21]
    • Malawi has an estimated average IQ of 60.
    • Singapore and Hong Kong have estimated IQs around 108.

(image from here)

  • A large survey published in one of the top psychology journals polled over 250 experts on IQ and international intelligence differences. [21]
    • On possible causes of cross-national differences in cognitive ability: “Genes were rated as the most important cause (17%), followed by educational quality (11.44%), health (10.88%), and educational quantity (10.20%).”
    • “Around 90% of experts believed that genes had at least some influence on cross-national differences in cognitive ability.”
  • Men and women have equal average IQs.
    • But: “most IQ tests are constructed so that there are no overall score differences between females and males.” [6]
    • They do this by removing items that show significant sex differences. So, for instance, men have a 1 SD (15 point) advantage on visual-spatial tasks over women. Thus mental rotation tests have been removed, in order to reduce the perception of bias. [22]
    • Males also do better on proportional and mechanical reasoning and mathematics, while females do better on verbal tests. [22]
  • Hormones are thought to play a role in sex differences in cognitive abilities. [23]
    • Females that are exposed to male hormones in utero have higher spatiotemporal reasoning scores than females that are not. [24]
    • The same thing is seen with men that have higher testosterone levels, and older males given testosterone. [25]
  • There is also some evidence of men having a higher IQ variance than women, but this seems to be disputed. If true, it would indicate more men at the very bottom and the very top of the IQ scale (helping to explain sex disparities in high-IQ professions). [26]

IQ Trends

  • In the developed world, average IQ has been increasing by 2 to 3 points per decade since 1930. This is called the Flynn effect.
    • The average IQ in the US in 1932, as measured by a 1997 IQ test, would be around 80. People with IQ 80 and below correspond to the bottom 9% of the 1997 population. [27]
  • Some studies have found that the Flynn effect seems to be waning in the developing world, and beginning in the developing world. [28]
  • A large survey of experts found that most attribute the Flynn effect to “better health and nutrition, more and better education and rising standards of living.” [29]
  • The Flynn effect is not limited to IQ tests, but is also found in memory tests, object naming, and other commonly used neuropsychological tests. [30]
  • Many studies indicate that the black-white IQ gap in the United States is closing. [23]

Can IQ be increased?

  • There are not any known interventions to reliably cause long term increases (although decreasing it is easy).
    • Essentially, you can do a handful of things to ensure that your child’s IQ is not low (give them access to education, provide them good nutrition, prevent iodine deficiency, etc), but you can’t do much beyond these.
  • Educational intervention programs have fairly unanimously failed to show long-term increases in IQ in the developed world. [23]
    • The best prekindergarten programs have a substantial short-term effect on IQ, but this effect fades by late elementary school.

Random curiosities

  • Several large-scale longitudinal studies have found that children with higher IQ are more likely to have used illegal drugs by middle age. This association is stronger for women than men. [31][32]
    • This actually makes some sense, given that IQ is positively correlated with Openness (in the Big Five personality traits breakdown).
  • The average intelligence of Marines has been significantly declining since 1980. [33]
  • “The US military has minimum enlistment standards at about the IQ 85 level. There have been two experiments with lowering this to 80 but in both cases these men could not master soldiering well enough to justify their costs.” (from Wiki)
    • This is fairly terrifying when you consider that 10% of the US population has an IQ of 80 or below; evidently, this enormous segment of humanity has an extremely limited capacity to do useful work for society.
  • Researchers used to think that IQ declined significantly starting around age 20. Subsequently this was found to be mostly a product of the Flynn effect: as average IQ increases, the normed IQ value inflates, so a constant IQ looks like it decreases. (from Wiki)
  • The popular idea that listening to classical music increases IQ has not been borne out by research. (Wiki)
  • There’s evidence that intelligence is part of the explanation for differential health outcomes across socioeconomic class.
    • “…Health workers can diagnose and treat incubating problems, such as high blood pressure or diabetes, but only when people seek preventive screening and follow treatment regimens. Many do not. In fact, perhaps a third of all prescription medications are taken in a manner that jeopardizes the patient’s health. Non-adherence to prescribed treatment regimens doubles the risk of death among heart patients (Gallagher, Viscoli, & Horwitz, 1993). For better or worse, people are substantially their own primary health care providers.”

      “For instance, one study (Williams et al., 1995) found that, overall, 26% of the outpatients at two urban hospitals were unable to determine from an appointment slip when their next appointment was scheduled, and 42% did not understand directions for taking medicine on an empty stomach. The percentages specifically among outpatients with inadequate literacy were worse: 40% and 65%, respectively. In comparison, the percentages were 5% and 24% among outpatients with adequate literacy. In another study (Williams, Baker, Parker, & Nurss, 1998), many insulin-dependent diabetics did not understand fundamental facts for maintaining daily control of their disease: Among those classified as having inadequate literacy, about half did not know the signs of very low or very high blood sugar, and 60% did not know the corrective actions they needed to take if their blood sugar was too low or too high. Among diabetics, intelligence at time of diagnosis correlates significantly (.36) with diabetes knowledge measured 1 year later (Taylor, Frier, et al., 2003).” [34]
  • IQ differences might be able to account for a significant portion of global income inequality.
    • “… in a conventional Ramsey model, between one-fourth and one-half of income differences across countries can be explained by a single factor: The steady-state effect of large, persistent differences in national average IQ on worker productivity. These differences in cognitive ability – which are well-supported in the psychology literature – are likely to be malleable through better nutrition, better education, and better health care in the world’s poorest countries. A simple calibration exercise in the spirit of Bils and Klenow (AER, 2000) and Castro (Rev. Ec. Dyn., 2005) is conducted. According to the model, a move from the bottom decile of the global IQ distribution to the top decile will cause steady-state living standards to rise by between 75 and 350 percent. I provide evidence that little of IQ-productivity relationship is likely to be due to reverse causality.” [35]
  • Exposure to lead hampers cognitive development and lowers IQ. You can calculate the economic boost the US received as a result of the dramatic reduction in children’s exposure to lead since the 1970s and the resulting increase in IQs.
    • “The base-case estimate of $213 billion in economic benefit for each cohort is based on conservative assumptions about both the effect of IQ on earnings and the effect of lead on IQ.” [36]
    • Yes. $213 billion.
  • In a 113-country analysis, IQ has been found to positively affect all main measures of institutional quality.
    • “The results show that average IQ positively affects all the measures of institutional quality considered in our study, namely government efficiency, regulatory quality, rule of law, political stability and voice and accountability. The positive effect of intelligence is robust to controlling for other determinants of institutional quality.” [37]
  • High IQ people cooperate more in repeated prisoner’s experiments; 5% to 8% more cooperation per 100 point increase in SAT score (7 pt IQ increase). [38][39]
    • The second paper also shows more patience and higher savings rates for higher IQ. [39]
  • Embryo selection is a possible way to enhance the IQ of future generations, and is already technologically feasible.
    • “Biomedical research into human stem cell-derived gametes may enable iterated embryo selection (IES) in vitro, compressing multiple generations of selection into a few years or less.” [40]
      Selection Average IQ gain
      1 in 2 4.2
      1 in 10 11.5
      1 in 100 18.8
      1 in 1000 24.3

Sources

There is a ridiculous amount of research out there on IQ, and you can easily reach any conclusion you want by just finding some studies that agree with you. I’ve tried to stick to relying on large meta-analyses, papers of historical significance, large surveys of experts, and summaries by experts of consensus views.

[1] Warne, R. T., Astle, M. C., & Hill, J. C. (2018). What Do Undergraduates Learn About Human Intelligence? An Analysis of Introductory Psychology Textbooks. Archives of Scientific Psychology, 6(1), 32-50.

[2] Gottfredson, L. S. (1997). Mainstream science on intelligence: An editorial with 52 signatories, history and bibliography. Intelligence, 24(1), 13-23.

[3] Colom, R. (2004). Intelligence Assessment. Encyclopedia of Applied Psychology, 2(2), 307–314.

[4] Batty, D. G., Deary, I. J,, Gottfredson, L. S. (2007).  Premorbid (early life) IQ and Later Mortality Risk: Systematic ReviewAnnals of Epidemiology, 17(4), 278–288.

[5] Gottfredson, L. S. (1997). Why g Matters: The Complexity of Everyday LifeIntelligence, 24(1), 79-132.

[6] Neisser, U, et al. (1996). Intelligence: Knowns and Unknowns. American Psychological Association. American Psychologist, 51(2), 77-101.

[7] Deary, I. J., et al. (2007). Intelligence and educational achievementIntelligence, 35(1), 13-21.

[8] Dumfart, B., & Neubauer, A. C. (2016). Conscientiousness is the most powerful noncognitive predictor of school achievement in adolescents. Journal of Individual Differences, 37(1), 8-15.

[9] Kuncel, N. R., & Hezlett, S. A. (2010). Fact and Fiction in Cognitive Ability Testing for Admissions and Hiring DecisionsCurrent Directions in Psychological Science, 19(6), 339-345.

[10] Schmidt, F. L., Hunter, J. E. (1998). The Validity and Utility of Selection Methods in Personnel Psychology: Practical and Theoretical Implications of 85 Years of Research FindingsPsychological Bulletin, 124(2), 262-274.

[11] Hunter, J. E., & Hunter, R. F. (1984). Validity and utility of alternative predictors of job performancePsychological Bulletin, 96(1), 72-98.

[12] Watkins, M. W., Lei, P., Canivez, G. L. (2007). Psychometric intelligence and achievement: A cross-lagged panel analysisIntelligence, 35(1), 59-68.

[13] Deary, I. J., et al. (2000). The stability of individual differences in mental ability from childhood to old age: follow-up of the 1932 Scottish Mental Survey. Intelligence, 28(1), 49–55.

[14] Frangou, S., Chitins, X., Williams, S. C. R. (2004). Mapping IQ and gray matter density in healthy young people.  NeuroImage, 23(3), 800-805.

[16] Narr, K., et al. (2007). Relationships between IQ and Regional Cortical Gray Matter Thickness in Healthy Adults. Cerebral Cortex, 17(9), 2163–2171.

[15] University Of California – Irvine. “Human Intelligence Determined By Volume And Location Of Gray Matter Tissue In Brain.” ScienceDaily, 20 July 2004.

[17] Deary, I. J., Penke, L., Johnson, W. (2010) The neuroscience of human intelligence differencesNature Reviews Neuroscience, 11(3), 201–211.

[18] Deary, I. J., Johnson, W., Houlihan, L. M. (2009). Genetic foundations of human intelligenceHuman Genetics, 126(1), 215-232.

[19] Davies, G., et al. (2011). Genome-wide association studies establish that human intelligence is highly heritable and polygenicMol Psychiatry, 16(10), 996–1005.

[20] Rushton, J. P., Jensen, A. R. (2005). Thirty Years of Research on Race Differences in Cognitive AbilityPsychology, Public Policy, 11(2), 235-294.

[21] Rindermann, H., Becker, D., Coyle, T. R. (2016). Survey of Expert Opinion on Intelligence: Causes of International Differences in Cognitive Ability TestsFrontiers in Psychology, 7.

[22] Ellis, L., et al. (2008). Sex Differences: Summarizing More than a Century of Scientific Research. Psychology Press.

[23] Nisbett, R. E., et al. (2012). Intelligence: New Findings and Theoretical DevelopmentsAmerican Psychologist, 67(2), 129.

[24] Resnick, S. M., et al. (1986). Early hormonal influences on cognitive functioning in congenital adrenal hyperplasiaDevelopmental Psychology, 22(2), 191-198.

[25] Janowsky, J. S., Oviatt, S. K., Orwoll, E. S. (1994) Testosterone influences spatial cognition in older men. Behavioral Neuroscience, 108(2), 325-332.

[26] Lynn, R., Kanazawa, S. (2011). A longitudinal study of sex differences in intelligence at ages 7, 11 and 16 yearsPersonality and Individual Differences, 51(3), 321–324.

[27] Neisser, U. (1997). Rising Scores on Intelligence Tests. American Scientist, 85(5), 440-447.

[28] Pietschnig, J., Voracek, M. (2015). One Century of Global IQ Gains: A Formal Meta-Analysis of the Flynn Effect (1909-2013)Perspectives on Psychological Science, 10(3), 282-306.

[29] Rindermann, H., Becker, D., Coyle, T. R. (2017). Survey of expert opinion on intelligence: The Flynn effect and the future of intelligence. Personality and Individual Differences, 106, 242-247.

[30] Trahan, L. H., et al. (2014). The Flynn Effect: A Meta-analysisPsychological Bulletin, 140(5), 1332-1360.

[31] White, J., Gale, C. R., Batty, D. G. (2012). Intelligence quotient in childhood and the risk of illegal drug use in middle-age: the 1958 National Child Development SurveyAnnals of Epidemiology, 22(9), 654-657.

[32] White, J., Batty, D. G. (2011). Intelligence across childhood in relation to illegal drug use in adulthood: 1970 British Cohort Study. Journal of Epidemiology & Community Health, 66(9).

[33] Cancian, M. F., Klein, M. W. (2015). Military Officer Quality in the All-Volunteer ForceNational Bureau of Economic Research, WP 21372.

[34] Gottfredson, L.S. (2004). Intelligence: Is it the epidemiologists’ elusive fundamental cause of social class inequalities in health?Journal of Personality and Social Psychology86(1), 174-199.

[35] Jones, G. (2005). IQ in the Ramsey Model: A Naive Calibration. George Mason University.

[36] Grosse, S. D., et al. (2002). Economic Gains Resulting from the Reduction in Children’s Exposure to Lead in the United StatesEnvironmental Health Perspectives, 110(6), 563-569.

[37] Kalonda-Kanyama, I. & Kodila-Tedika, O. (2012). Quality of Institutions: Does Intelligence Matter?Working Papers Series in Theoretical and Applied Economics 201206, University of Kansas, Department of Economics.

[38] Jones, G. (2008). Are Smarter Groups More Cooperative? Evidence from Prisoner’s Dilemma Experiments, 1959-2003Journal of Economic Behavior & Organization 68(3–4), 489-497.

[39] Jones, G. (2011). National IQ and National Productivity: The Hive Mind Across Asia. Asian Development Review, 28(1), 51-71.

[40] Shulman, C. & Bostrom, N. (2014). Embryo Selection for Cognitive Enhancement: Curiosity or Game-changer?. Global Policy 5(1), 85-92.