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- A Northwestern University study shows a decline in three key intelligence testing categories—a tangible example of what is called the Reverse Flynn Effect.
- Leading up to the 1990s, IQ scores were consistently going up, but in recent years, that trend seems to have flipped. The reasons for both the increase and the decline are sill very much up for debate.
- Scores in verbal reasoning, matrix reasoning, and letter and number series all declined but, interestingly, scores in spatial reasoning went up.
Americans’ IQ scores are trending in a downward direction. In fact, they’ve been falling for over a decade.
According to a press release, in studying intelligence testing data from 2006 to 2018, Northwestern University researchers noticed that test scores in three out of four “cognitive domains” were going down. This is the first time we’ve seen a consistent negative slope for these testing categories, providing tangible evidence of what is known as the “Reverse Flynn Effect.”
In a 1984 study, James Flynn noticed that intelligence test scores had steadily increased since the early 1930s. We call that steady rise the Flynn Effect. Considering that overall intelligence seemed to be increasing faster than could be explained by evolution, the reason increase became a source of debate, with many attributing the change to various environmental factors.
But now, it seems that a Reverse Flynn Effect is, well, in effect.
The study, published in the journal Intelligence, used an online, survey-style personality test called the Synthetic Aperture Personality Assessment Project to analyze nearly 400,000 Americans. The researchers recorded responses from 2006 and 2018, in order to examine if and how cognitive ability scores were changing over time within the country. The data showed drops in logic and vocabulary (known as verbal reasoning), visual problem solving and analogies (known as matrix reasoning), and computational and mathematical abilities (known as letter and number series).
On the flip side, however, scores in spatial reasoning (known as 3D rotation) followed the opposite pattern, trending upward over the 12-year period. “There’s a debate about what’s causing it, but not every domain is going down; one of them is going up,” Elizabeth Dworak, a research assistant professor at Northwestern University and one of the authors on the study, says in a news release. “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.”
Dworak, a research assistant professor at Northwestern University and one of the authors on the study, is very clear that these results don’t necessarily mean 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,” she said in a press release. “It could just be that they’re getting worse at taking tests or specifically worse at taking these kinds of tests.”
And, it should be said, there has long been debate over how accurately IQ tests are able to gauge overall intelligence and potential for success in society in the first place.
Regardless, scores are falling, and there’s got to be a reason for the decline. Dworak says it might have something to do with “a shift in perceived values in society.” She offers up the potential explanation that an increase in focus on STEM education may have allowed other areas, like abstract reasoning, to fall by the wayside.
“If you’re thinking about what society cares about and what it’s emphasizing and reinforcing every day,” she says, “there’s a possibility of that being reflected in performance on an ability test.”
A few other hypotheses have been put forth to try and explain the reverse Flynn Effect, such as falling nutritional standards, the worsening of school systems, social media, increased air pollution, or the idea that people just be less interested in portions of the SPAP Project personality survey.
Falling IQs have become yet another mystery for scientists to solve.
