This lesson is a puzzle. Begin by imagining a trait associated with cognitive skills. Intelligence is one example, but you could just as well consider specific skills such as mathematics, verbal ability, spatial ability, or memory. Your task is to think of a society, give it certain numerical values on attributes that contribute to the cognitive skill, and then examine the heritability of the cognitive skill in the society.
Above there are four attributes that are associated with the cognitive skill-Education, Attitude to Education, Skill Encouragement, and Literacy. To the right of each skill there are two anchor points with a text field in between. To fashion your society, enter a numerical value between 0 and 100 into the text box to reflect the degree to which the society as a whole emphasizes the choice. The closer the number is to 0, the more the society resembles the left anchor point and the closer to 100, the more the society resembles the right anchor point. For example, if you enter a 0 into the text field for Education, then the society has no formal educational system as happens in certain preliterate hunter-gatherer cultures. If you enter 100 into the same field, then the society demands and has compulsory formal education as most industrialized countries have today. A value of 50 might reflect a society like Western Europe several hundred years ago in which some people were well educated but many never went to school at all.
It is crucial to understand that the number that you enter reflects the valence or the strength to which a society holds certain views. For example, a 0 in the text fields for Skill Encouragement means that everyone in the society rewards and encourages manual skills. Values that are close to 0, but not actually equal to 0, signify that the majority in the society prefers and encourages the development of manual over intellectual skills but not everyone in the society shares this opinion. A value of 50 would mean that the society is evenly split--half of the population encourages the development of manual skills while the other half supports the development of intellectual ability.
Heritability I: Scatterplots
Heritability II: Environmental variation around a genotypic value.
Heritability IV: Between-group Heritability.