Are we growing more dumber? Americans’ IQ scores drop in four of five measurements

EVANSTON, Ill. —  IQ scores significantly increased from 1932 through the 20th century all over the world, with differences ranging from roughly three to five IQ points per decade. This phenomenon is known as the “Flynn Effect.” Now, however, a new study out Northwestern University suggests a “reverse-Flynn Effect” of sorts may be taking place in the United States.

This reverse-Flynn Effect was present across a large U.S. sample covering between 2006 and 2018 in every category — except one. Still, there were consistent negative slopes among three out of four cognitive domains.

Ability scores pertaining to verbal reasoning (logic, vocabulary), matrix reasoning (visual problem solving, analogies), and letter and number series (computational/mathematical) all dropped over the course of the study period. However, scores of 3D rotation (spatial reasoning) generally increased between 2011 to 2018.

Composite ability scores (single scores derived from multiple pieces of information) were also lower across the more recent samples. These score differences persisted regardless of age, education, or gender.

Sugarcoating the findings?

Despite the observed decline in IQ scores, corresponding study author Elizabeth Dworak posits people shouldn’t read these findings and think, “Americans are getting less intelligent.

“It doesn’t mean their mental ability is lower or higher; it’s just a difference in scores that are favoring older or newer samples,” explains Dworak, a research assistant professor of medical social sciences at Northwestern University Feinberg School of Medicine, in a media release. “It could just be that they’re getting worse at taking tests or specifically worse at taking these kinds of tests.”

Study authors used the Synthetic Aperture Personality Assessment (SAPA) Project, a free survey-based online personality test that gives test-takers feedback focusing on 27 temperament traits (adaptability, impulsivity, anxiety, humor), in addition to their ability scores.

Person filling out an IQ test
Are Americans less intelligent or just performing worse on IQ tests? (© jirsak –

Survey responses were analyzed from 394,378 Americans collected between 2006 to 2018 in an attempt to examine if cognitive ability scores changed over those 13 years. A smaller cohort of individuals (303,540) was also recruited between 2011 and 2018. The 3D rotation data, though, only exists for subjects who took the survey between 2011 and 2018.

More IQ scores needed

This project did not attempt to determine the reason for the decline in IQ scores. That being said, researchers add there is no shortage of possible explanations and theories in the scientific community, ranging from poor nutrition,  and worsening health to media exposures and changes to education. “There’s debate about what’s causing it, but not every domain is going down; one of them is going up,” Prof. Dworak notes. “If all the scores were going in the same direction, you could make a nice little narrative about it, but that’s not the case. We need to do more to dig into it.”

To that end, Prof. Dworak and her colleagues are now attempting to access a dataset containing 40 years worth of data in order to conduct a follow-up study.

A change in societal values may have also affected IQ scores, Prof. Dworak adds. “If you’re thinking about what society cares about and what it’s emphasizing and reinforcing every day, there’s a possibility of that being reflected in performance on an ability test,” she continues.

For example, there’s been more emphasis on STEM education in recent decades. So, does that mean other academic areas, like abstract reasoning, are receiving less attention in schools?

Yet another factor could be a drop off in motivation. Since the SAPA Project is advertised as a personality survey, individuals who enrolled may have been more engaged with sections related to the measurement of temperament and less engaged with sections seemingly unrelated to personality.

And yes, there’s some tongue-in-cheek wordplay up there in the headline.

The study is published in Intelligence.

Follow on Google News

About the Author

John Anderer

Born blue in the face, John has been writing professionally for over a decade and covering the latest scientific research for StudyFinds since 2019. His work has been featured by Business Insider, Eat This Not That!, MSN, Ladders, and Yahoo!

Studies and abstracts can be confusing and awkwardly worded. He prides himself on making such content easy to read, understand, and apply to one’s everyday life.

The contents of this website do not constitute advice and are provided for informational purposes only. See our full disclaimer


  1. Well, from all the people commenting on the, “more dumber”, part of the headline, you can tell reading comprehension has dropped. It’s explained in the last sentence, but that would mean the story would need to be read. Also, that people are trying to bring race into the story really shows that the lower IQs seem to be spread across the board.

    1. The racial makeup of the US population has changed dramatically in the past several generations. I don’t think bringing up race should be verboten. For instance the average IQ of Somalis and Afghanis is in the 70s. And up until the the 1980s there was no category for Americans of Hispanic ancestry because there were not enough of them. Now?

    2. Would you have a problem with someone saying the average height of Americans has declined in the past 40 years? Out of 40 million Hispanic Americans could their average height be bringing down the national average? I have never run into an Hispanic taller than me. I know there are some out there, but…..

    3. I missed that until you pointed it out, ouch. I guess I have gotten increasingly tolerant of spelling, wrong words and grammar in the media.

    4. Oh, one more point on the height analogy(?). I live in Houston, I am only 6’4”. On any given day it is a toss up who I will have more interaction with, Hispanics or Anglos. All Hispanic Americans are shorter than me. Non Hispanic Americans? 20% are taller than me? Your sanctimonious post is just wrong. Cheers

  2. Idiocracy come to life. Terry Crews for President! (Not implying that Mr. Crews is anything less than a national treasure).

  3. Teachers scream for more money, but they do a poor job of preparing young people to succeed in life.

      1. Perhaps we spend too much on non-classroom frills like bloated administration. The USA spends more than any other country on education and is in the top 4 in per-student expenditures.

  4. I wouldn’t doubt there are multiple influences at play here, however, anyone with a shred of intellectual honesty who has not been completely overcome and captured by current politics would immediately recognize that this is almost certainly a direct consequence of migration to the USA from the global south. You don’t have to be a scientist, the evidence is all around you depending on where you live. It’s not a risky or difficult prediction that as migration continues to flood the USA we will see the Flynn effect completely negated and more likely see IQ avg lowering as the number of immigrants from areas of sub-100 avg IQ increases in population. If you have an area filled with people where the avg IQ is 100 and you then flood that area with a group of people with an avg IQ of 85-95 guess what happens to the country’s avg IQ.
    I am not placing a value judgment on immigration or IQ, I’m only pointing out the obvious. The fact that this data touches on immigration and demographic “rollover” means it indirectly touches on the issue of race and IQ which we all know is absolutely verboten. Therefore we must ignore the most obvious and come up with a plethora of much less plausible factors. This is evidenced in the article, as the main driving force of the data is completely missing from the report. My personal opinion is that however uncomfortable or messy, our inability to speak openly about reality will end up causing more destruction and human suffering than the perceived evil of acknowledging what we know to be the true state of the world and human biodiversity.

    1. Moderator, where is my post about written language and two story buildings in sub Saharan Africa? Seriously? You deleted it?

  5. If we presume that intelligence increased throughout our evolution as a benefit to survival, who now could be surprised at our decreasing intelligence, given that governments now guarantee our survival, no matter how stupidly we behave?

    1. Good point. To put it another way, self-responsibility is being replaced by nanny state.

  6. None are taught to observe and organize their own minds. This leads to errors in judgement which always leads to mistakes. One must have a resting mind to observe correctly. Teach kids how to think, not what to think.

  7. USA spends more on education than any other country and is in the top 4 in terms of expnditures per student. Throwing more money into our underperforming education system is not working. The system itself is a large portion of the problem, and so is demographic change. Adding millions of immigrant students whose first language is not English is exacerbating the problem.

    1. That’s complete hogwash. Has nothing to do with the language someone speaks. In fact, immigrants do BETTER in school then non-immigrants. Keep your ignorant bias to yourself.

      1. In Texas 28% of students pre-K to 3rd grade are English-learning (English as second language) students, predominantly Hispanic and first or second generation immigrants.
        In Texas, Asian students as a whole do better than non-immigrants as a whole, but Hispanic immigrants do not.

  8. IQ’s are going down but intellectual arrogance is on the rise. It’s surprising just how many mental deficients vote. We elected a president who doesn’t even know where he is half the time and in my state of PA they elected a guy that didn’t know the beginning of a debate from the end. Yet, the ones who voted for them are incredibly arrogant and have no self-awareness whatsoever.

    1. Republicans have the two dumbest people ever elected to congress, MTG and Boebert, and tried to get a man who has literal severe brain damage from football elected as a senator (not to mention wife and child beating). Everyone outside your little online echo chambers are disgusted by Republican behavior, trying to take us back to the 1950s. Republicans are by far less educated then democrats, hence why you all are trying to defund libraries and ban books and public school. Because you know education helps make you a caring human being, and Repugs can’t have that.

      1. You are no better than they are, just the reverse side of the same coin.

        Anyone who engages in ideology has abdicated their responsibility to think about the issues, which is why your post is exactly like the conservative posts. You’re simply repeating talking points you heard on your favorite ideologically slanted news channel.

        The people on the extremes are not the cream of the crop intellectually. You’re ruining our country with division and by demonizing people you don’t agree with.

      2. I don’t have a dog in this ideological fight. But I did find curious your comment that Rep. are trying to take us back to the 1950s. That was the era of McCarthyism where everyone was suspected of being a traitorous Russian sympathizer, when Russia was the feared for its attempts to take over the American political system. Does that ring a bell with the narrative since 2016, purchased and pushed by Hillary? And keep in mind that Hillary was a Goldwater supporter back in 1960.

    2. I’d like to provide an honest opinion, but those are being censored by this leftist site.

    3. You voted for a guy who has had more failed business ventures than Carter had pills. Someone who suggested that bright lights and disinfectants would cure COVID. A person who suggested that forest fires could be prevented by raking the forest floors. A man who lies every time his lips are moving. Should I go on? Let’s not talk about how other people arrogant or have no self-awareness. Check the mirror.

      1. Have you seen a hospital room cleaned recently or ever? In the Texas Medical Center in Houston all the world famous hospitals wheel in a strobe like machine and let it flash for ten minutes to CLEAN and DISINFECT the room. Now shush……

      2. Forest management absolutely can prevent fires. That absolutely means removing debris that can cause fires. Yearly California forest fires are caused by lack of forest management not global warming.

      3. you seem to be absolutely clueless regarding every “point” you’ve made a feeble attempt on.
        tell us you know nothing about fire mitigation, without telling us
        tell us you know nothing about UVC disinfection process, without telling us

        Just don’t break your mirror, while checking your own self..

  9. It’s an uncomfortable fact that there are IQ differences based on genetic makeup, and the genetic makeup of the country is changing.

    1. Do you mean the party whose members are more likely to have white-collar jobs and a college education?

      Try again.

      1. More likely to work for guvment you mean. Less likely to start a business and do something productive.

        MENSA member, small business owner, and anti dim-ocrat.

  10. The fact that there is an obvious grammatical error in the title of this story is all the evidence you need to that we are in fact growing “more dumber.”

  11. Interesting the nature of the majority of comments made here. “Study Finds” appears to be a website with very low bias. People reading this are just looking for “facts”. Academia and media [curious how academia and media are almost anagrams.] But anyway, academia and media will tell you the more “educated” you are, i.e. the more formal education one has, the more likely you are to vote democrat. It may be the findings in this study explains the last presidential election. Do the majority of comments here seem to confirm this observation.?

    1. Media and academia, who both have incredibly percentage of leftist and vote lock-step Democratic tell us that the more educated you are the more likely you are to vote Democrat? Wow, that just floored me. I never would have expected that result.

  12. We’ll just do what all good Liberals do, just lower the IQ standards and make everybody smarter.

  13. “Are we growing more dumber?”

    More dumber!?!?

    Geez! I hope that headline is meant as a joke!

    1. I would wager a joke that too many people didn’t get. Writing grammatically evaporated with the emergence of texting.

  14. “More dumber”, a double comparative, is an example of improper English. So to the article’s question, I’d say yes.

Comments are closed.