IQ and psychometrics

This study explains why Americans’ vocabulary skills are dropping

vocabulary skills

A widely researched phenomenon known as the Flynn Effect suggests that IQ scores have been increasing for decades. Yet a recent study of 30,000 Americans has found that their vocabulary skills, an important component of intelligence, have shown no such increase.

This is an odd development. After all, more students finish high school today than they did in the 1970s. And more of those high school graduates go on to attend college. If more education leads to greater verbal skills, then vocabulary should increase.

The study was based on the General Social Survey (GSS), a demographically representative sample of Americans over the age of 18. The GSS was launched in 1972, and is still running today. It gathers information about the attitudes, behaviors, and concerns of people who live in the United States. The number of GSS respondents included in the current study was just under 30,000.

More graduates, but worse vocabulary skills

Part of the GSS involves a 10-question vocabulary test. Participants are also asked to report their highest level of education.

The researchers found, as expected, that educational attainment has increased over the decades, from an average of 11.83 years in 1974 to 13.68 years in 2016. And, also as expected, years of education correlated strongly (0.47) with vocabulary, meaning that people with higher levels of education generally have better vocabulary skills.

But Americans’ scores on the GSS vocabulary test did not change much between 1974 and 2016. And that’s despite many more people graduating from high school and college. When the researchers took years of education into account, vocabulary scores actually declined.

Specifically, those with a bachelor’s or graduate degree had the largest decrease: the vocabulary of American college graduates declined by more than a half a standard deviation over these four decades. Likewise, vocabulary levels also dropped among people who did not go to college.

The average vocabulary of an American is in decline

The vocabulary gap between educational levels has narrowed considerably. The gap between high school drop-outs and college graduates has narrowed the most. From 1974-1979, the difference between those two groups on the GSS vocabulary test was about 3.4 correct answers (out of a possible 10). But by 2016, that difference had dropped to 2.9 correct answers.

The authors suggest several reasons to explain this drop. One is that over the decades, high school students have spent less and less time reading. Accordingly, verbal scores on the SAT have also declined (PDF) in the same period.

Another possibility is that the some of the words on the test may have fallen out of fashion, and are now less known. Or, more generally, perhaps American culture itself has become “less intellectual, either because of or in response to a lowering of verbal ability among those who read books.”

In any case, “increased educational attainment has not led to increased verbal ability,” the authors write. And as a result, “the average vocabulary of an American college graduate is now lower than in the past.”

A 2016 study estimated that the average vocabulary of an American is about 42,000 words at the age of 20.


Other recent science and psychology news:

  • Analyzing Google searches for certain keywords predicted regional COVID-19 outbreaks up to 2 weeks in advance, new research finds.
  • Not wearing a mask makes the size of your “cough cloud” between 7 and 23 times bigger than it otherwise would be.
  • Compared to using bus apps, people would get better results by just randomly walking to the bus stop.
  • A new study has found that people low in neuroticism and high in openness are less likely to follow shelter in place rules.
  • Guns were found to be the most common suicide method for Whites and African Americans, vs. hanging for Latinos and Asians.

Study: “Declines in vocabulary among American adults within levels of educational attainment, 1974-2016” (link)
Authors: Jean M. Twenge, W. Keith Campbell, and Ryne A. Sherman
Published in: Intelligence, Volume 76, September-October 2019
DOI: https://doi.org/10.1016/j.intell.2019.101377
Photo: by Yaroslav Shuraev from Pexels

Related posts
IQ and psychometrics

New study finds that teens with a high IQ are more liked by their peers, but less likely to like those peers back

New study finds that a high IQ increases the probability of being liked by peers, but also decreases the probability of liking them back.
IQ and psychometrics

New study of video gamers finds that Android users have higher IQ scores than iPhone users

Study on IQ scores of video gamers finds women outscore men, Android users outscore iPhone users, and Rainbow Six Siege is the smartest game.
IQ and psychometrics

IQ and EQ: new study finds that high-IQ people also have more emotional intelligence

IQ and EQ are closely linked: a new study finds that gifted people also have higher emotional intelligence levels.