To understand how scientists study the genetic and environmental factors that interact to produce variation in behavior across a population.
This is the first of two lessons about the field called behavioral genetics, in which scientists study the reciprocating influences of genes and environments on behavior, particularly human behavior.
Genes, Environments, and Behavior 1 provides students with a clear understanding of how behavior is defined by scientists and an overview of the genetic and environmental forces that interact to shape behavior.
Genes, Environments, and Behavior 2 introduces students to the various approaches scientists use to explore this interaction.
These lessons are based on the book, Behavioral Genetics: An introduction to how genes and environments interact through development to shape differences in mood, personality, and intelligence, published by AAAS and The Hastings Center. You may choose to print out chapters or to order copies of the book. The PDFs and ordering information may be obtained at the Behavioral Genetics Project.
By the end of elementary school, students should be well aware of the fact that individuals differ in their behavior. They also should understand that behavior is shaped by several factors, and that some of these factors are under their own control, for example:
- They learn some behaviors (as opposed to the behaviors being instinctual)
- Some of their behavior is influenced by families, friends, classrooms, and cultures
- Memories and learned information shape what they attempt to do and what they avoid doing
- Through repetition and practice they can improve a behavior (such as a skill)
(Benchmarks for Science Literacy, p. 108.)
By the end of middle school, students should be aware that behavior is affected not only by the world around them—their experiences—but also by their own biology—their genetic inheritance. (Benchmarks for Science Literacy, p. 108.) They also should understand that while some animal species are limited to a repertoire of genetically determined behaviors, other species (including and especially the human species) have more complex brains and their possible range of behaviors is therefore broader. (Benchmarks for Science Literacy, p. 141.)
In high school, students should be ready to study the specific ways that the variables of genetics and experience contribute to behavior. High-school students should learn that the interaction is extraordinarily complex and contingent, that scientists study the relative effects of genes and environment using a variety of techniques, and that we still have a great deal to learn about the interactive influences on behavior. Finally, students should recognize that the range of any human individual’s possible behaviors is great and each person can shape his or her own life to a significant degree. (Benchmarks for Science Literacy, pp. 142, 153.)
An important objective of these lessons is to help students overcome the common public misperception that genes have a direct relationship with behavior; for example, that there may be a “gene for criminality” or a “gene for religiosity.” Another common misperception that can be dispelled through these lessons is that the development of an organism is determined solely by genetic factors; this is called genetic determinism. Possibly the most important value of these lessons, therefore, is that they can help students understand why such beliefs are false.
This lesson is part of a group of lessons that focus on the social, behavioral, and economic sciences. These lessons are developed by AAAS and funded by the National Science Foundation Grant No. SES-0549096. For more lessons and activities that take a closer look at the social, behavioral, and economic sciences, be sure to check out the SBE Project page.
To engage students in the topic, have them use their What is Behavioral Genetics? student esheet to go to and read the story, “Margaret, an ambitious mother,” from Chapter 1: What Is Behavioral Genetics?, published by AAAS and The Hastings Center. Students can read the story online via the student esheet, in books you have ordered, or on pages you have printed out. Alternatively, you or a student can read the story aloud. The story is less than a page long, so this should take just a few minutes.
Lead a discussion with these questions:
- What factors would help or hinder Margaret’s plan to turn her daughter Cassandra into a professional golfer?
- In what ways is your behavior shaped by your parents?
- What other cultural factors shape your behavior?
- In what ways is your behavior shaped by in-born attributes?
- In what ways is your behavior shaped by your ability to make decisions and by the decisions you make?
Accept all responses and encourage students to support their opinions. The purpose of this activity is simply to draw out what students know or believe about behavior. Through discussion, they should realize that it is not always easy to distinguish between the various forces that shape our behaviors. Allow 10 to 15 minutes for this activity.
In this part of the lesson, students will study behavior in more depth by continuing their reading of the behavioral genetics book. To begin, have students use their student esheet to go to and read Chapter 1: What Is Behavioral Genetics? This is a chapter with relatively easy content. If you ask students to read it in class, this should take no more than ten minutes.
After students have finished reading, direct them to the What Is Behavior? quiz. You may choose to print out the quiz ahead of time, to give a hard copy to each student. Or, you may read aloud each of the 20 items in turn, asking students to vote on whether it is a behavior. You may choose to put the following definition of behavior on the board:
Behavior: The actions a living creature makes, as a whole, in response to the world around it.
The Answer Sheet links each correct response to supporting text in Chapter 1. After discussing each quiz item as a class, ask students to add other examples of behaviors to the list.
To continue the lesson, divide the class into two halves. Assign half Chapter 2: How Do Genes Work within Their Environments? and assign the other half Chapter 3: How Do Environments Impinge Upon Genetics?
When students are finished reading, divide them into small groups, each of which includes students from each half (that is, some who have read Chapter 2 and some who have read Chapter 3). Have each small group begin its work by reading together the story from Chapter 2 (about Hoda, a perplexed nurse). Then have each group complete the first part of the Genes, Environments, and Behavior student sheet, with the students who have already read Chapter 2 instructing and leading the others. Repeat this activity with Chapter 3 (about Skip, a regretful man). The Answer Sheet links terms with their definition and applications.
As homework, you may assign students to read the chapter they did not work on in class (Chapter 3 for the students that were first assigned Chapter 2, and vice versa).
You also may ask students, in class and/or as homework, to write a brief essay on one of these topics:
- Define “genetic determinism” and explain why it is not a scientific concept. Use terms introduced in Chapters 1-3.
- Define “developmental pathway” and describe how genes and environments interact to shape it. Use terms introduced in Chapters 1-3.
Alternatively, you may ask students to make posters illustrating these themes:
- The relationship of bases, DNA, genes, chromosomes, cells, and nervous system
- The relationship of genes, proteins, and behaviors
- The various environmental influences on a given human being
Follow this lesson with the second lesson in the series: Genes, Environments, and Behavior 2.
Other websites that support the learning in this lesson include:
- Who am I?, from the National Science Museum (United Kingdom), is a brief, picture-based tour about genes that includes the section “Genes and Human Behaviour.”
- What Makes You YOU?, produced by the American Museum of Natural History, is a quick activity that conveys the relationship between individuals, traits, genes, chromosomes, and DNA.
- Tour of the Basics, created by the Genetic Science Learning Center, introduces students to DNA, genes, chromosomes, proteins, inheritance, and traits. If students only have time for one unit, direct them to “What is a Trait?”
- How do genes direct the production of proteins?, from the National Library of Medicine, includes a short description and illustration of “the flow of information from DNA to RNA to proteins.”