Genes, Environments, and Behavior

Genes, Environments, and Behavior Photo Credit: Clipart.com


Why do humans range so widely in their susceptibility to mental illness, in their willingness to take risks, and in their performance in intelligence tests? One answer to this question comes from scientists in the field of behavioral genetics. They say that the variation in behavioral traits across a population is due, in part, to an organism’s genetic make-up. In this lesson, you will learn how scientists study the interaction of genes with environments to produce variation in behavior across a population.


Begin by reading Anja, an identical twin, a story that serves as introduction to Chapter 4 of the publication, Behavioral Genetics: An introduction to how genes and environments interact through development to shape differences in mood, personality, and intelligence.
Check with your teacher before continuing.

As directed by your teacher, look at the research summary of Major Affective Disorders from the website, Online Mendelian Inheritance in Man. Print out a hard copy of the first five pages of this summary.

As you read the selection, conduct a scavenger hunt for phrases that reference research methods. Use a highlighter to mark the phrases you find in the research summary.

Look for phrases that reference research methods, including:

  • Family studies (including twin and adoption)
  • Molecular studies
  • Brain imaging studies

Conduct additional scavenger hunts (using different colored highlighters) for:

  • Locations mentioned where genetic research into Major Affective Disorder has been studied
  • Use of the word “suggested” and other qualifying, non-definitive phrases to describe study findings
  • Use of phrases that suggest a disconfirmed hypothesis (focus this search on p. 4)

Knowledge Check

Write a brief essay focusing on one particular behavioral trait (for example: altruism, intelligence, risk-taking) and suggesting how it might be researched through:

  1. Animal studies
  2. Family studies
  3. Genetic studies
  4. Brain imaging studies

The Image Archive on the American Eugenics Movement, produced by Cold Harbor Laboratory Dolan DNA Learning Center, can give you some insight into early methods used by scientists to study behavioral traits. It candidly portrays the flaws in that research and the ramifications when flawed research is applied to social policy such as immigration and sterilization laws. If you have limited time, focus on the exhibits: “Research Methods” and “Research Flaws.”

This esheet is a part of the Genes, Environments, and Behavior 2 lesson.

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