Monday, August 3, 2009

Brief: science knowledge across the lifespan

For the first of the brief posts (which don't count toward the 20 articles you've paid for), let's take a quick look at how knowledge of basic concepts in math and science changes -- or doesn't -- with age. It seems a priori unlikely that knowledge would continue to increase over time, since most people don't read more and more science or math during their lives. For most, there's what they were taught in school, and that's it. So, it could be like vocabulary size, which stays pretty constant through adulthood (or increases very slightly), or it could be like matching names with faces, where you forget people's names after not having seen them for so long.

The GSS has asked respondents 13 such basic science and math questions, mostly in True / False format, as follows:

- The center of the Earth is very hot.

- Human beings, as we know them today, developed from earlier species of animals.

- It is the father's gene that decides whether the baby is a boy or a girl.

- Does the Earth go around the Sun, or does the Sun go around the Earth?

- Electrons are smaller than atoms.

- Lasers work by focusing sound waves.

- The continents on which we live have been moving their locations for millions of years and will continue to move in the future.

- All radioactivity is man-made.

- Antibiotics kill viruses as well as bacteria.

- The universe began with a huge explosion.

- How long does it take for the Earth to go around the Sun: one day, one month, or one year?

- A doctor tells a couple that their genetic makeup means that they've got one in four chances of having a child with an inherited illness. a. Does this mean that if their first child has the illness, the next three will not have the illness?

- b. Does this mean that each of the couple's children will have the same risk of suffering from the illness?

I treated a correct answer as worth 1 point and an incorrect answer as worth 0. So, the average score that an age group gets on some question is simply the fraction who got it right. I weighted all 13 questions equally and summed up the scores for each question. Thus, if everyone missed every question, the total score is 0, while if everyone got every question, the total is 13. This way, the data have a clear and simple meaning: if you picked someone at random from some age group, how many questions out of all 13 would you expect them to get right?

The age groups are in 3-year intervals, starting with 18 - 20 and ending with 63 - 65 (to keep sample sizes around 40 or more). Here are the total scores on this basic science quiz by age group:

Aside from the anomaly of the 42 - 44 year-olds -- or maybe it's a sign of a mid-life crisis -- the data are pretty flat from young adulthood through retirement. There's a clear jump from the late high school / early college years to the late college / post-college years, although it decays somewhat during the 20s -- perhaps people are glad to not have to use this stuff anymore, so they don't keep up on it. During the 30s and mid-40s, though, there is a pretty evident steady increase. After that, it declines somewhat or is flat.

Like I said, though, there isn't much variance across the lifespan, so it seems that these factoids are like vocabulary words -- parts of your crystallized intelligence that you acquire when you're maturing, and that more or less stay put in your mind for the rest of your life. Given how little most people apply these factoids to their daily lives, there doesn't seem to be a strong "use it or lose it" component to remembering them.

As a final reminder, since you're paying to read this site, I'm much more open to reader suggestions about what to look at, for both the in-depth and these briefer posts. I have plenty of new ideas myself, but I'm sure there are many more that are floating around in readers' heads. I'll try to get to all of them, although how soon the results appear will obviously depend on how easy it is to attack the question.

GSS variables used: age, boyorgrl, evolved, hotcore, earthsun, electron, lasers, condrift, radioact, viruses, bigbang, solarrev, odds1, odds2.

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