Wednesday, October 14, 2009

Genes vs. environment, athletics   posted by Razib @ 10/14/2009 04:26:00 PM

The GSS variable GENENVO4:
Character, personality, and many types of behavior are influenced both by the genes people inherit from their parents and by what they learn and experience as they grow up. For each of the following descriptions, we would like you to indicate what percent of the person's behavior you believe is influenced by the genes they inherit, and what percent is influenced by their learning and experience and other aspects of their environment. The boxes on handcard D1 are arranged so that the first box on the LEFT (which is numbered 1) represents 100% genetic influence (and 0% environment). The next box (numbered 2) represents 95% genes (and 5% environment), and so on. The RIGHTMOST box (numbered 21) represents 100% environmental influence (and no genetic influence). After each description, please type the number of the box that comes closest to your answer. Please use the numbered scale on handcard D1 to indicate, FOR EACH OF THE BEHAVIORS DESCRIBED, what percent of the person's behavior you think is influenced by the genes they inherit, and what percent is influenced by their learning and experience. After each question, type the number of the box that comes closest to your answer. Remember, the higher the number, the more you think the behavior is influenced by learning and experience; the lower the number, the more you think it is influenced by genes 981. George is a Black man who's a good all-around athlete. He was on the high school varsity swim team and still works out five times a week. (Please type in a number from 1 to 21):

In other words, if someone gives the response 1, they think that George's athleticism is 100% a function of genes. 21, 100% a function of environment. The N for this variable is in excess of 2,000, and the question was asked in 2004. I decided to recode a bit so that responses were aggregated across 25% intervals like so: GENENVO4(r:1-6 "75% or more";7-11 "50% or more"; 12-16 "25% or more"; 17-21 "less than 25%"). If you want to poke around the GSS you can just cut & paste that into the "ROW" box. I was surprised at some of the results, first, the lack of difference across ages, as well as the similarity between liberals and conservatives. On the other hand, the dumb and uneducated were more likely to put an emphasis on genes, which went along with my expectations. The data are below in table form, and as well as a line graph (just to show you visually which ones deviate from the others).

% Genetic All Whites Black Male Liberal Conserv No College Degree College Degree Dumb Average Smart
75-100 21.1 19.3 29.6 21 21.7 19.6 24.2 13.8 28.2 23 15.1
50-75 27.8 28.7 28 26.4 29.4 24.6 26.5 31.1 31.9 26.8 27.6
25-50 22.4 23.4 16.2 23.1 24.8 24.5 20.5 27.1 11.2 22.4 25.6
0-25 28.6 28.6 26.2 29.4 24.1 31.3 28.9 28 28.7 27.8 31.7

At first when I saw little difference between liberals & conservatives and across age groups I wondered if it was coded wrong. But the outcomes for intelligence & education seem to fit. Perhaps it has something to do with George being a black athlete, so the intelligent and educated know what they should say about this sort of question?

Note: Dumb = WORDSUM 0-4, average WORDSUM 5-7 and smart WORDSUM 8-10.