Chapter 3: The Nature and Nurture of Behavior
Chapter 3 is concerned with the ways in which our biological heritage, or nature, interacts with our individual
experiences, or nurture, to shape who we are. After a brief explanation of basic terminology, the chapter discusses
psychology’s use of evolutionary principles to answer universal questions about human behavior. The next section
explores the fields of behavior genetics, which studies twins and adopted children to weigh genetic and environmental
influences on behaviors, and molecular genetics, which focuses on the specific genes that influence behavior.
The third section of the chapter shifts the spotlight to focus on environmental influences on behavior. The impact of
parents, the prenatal environment, early experience, peers, and culture on the development of the brain and behavior
are each discussed in depth. The final section of the chapter explores how genes and environment interact to shape
both the biological and social aspects of our gender. In the end, the message is clear: our genes and our experience
together form who we are.
Genes: Our Biological Blueprint
David Myers at times uses idioms that are
unfamiliar to some readers. If you do not
know the meaning of the following word in the
context in which it appears in the text, refer to
page 103 for an explanation:
First, skim this section, noting headings and boldface
items. Then read the following objectives and, as you
read the section, search for the information that will
enable you to meet each objective.
1. Identify the mechanisms of heredity.
2. Explain why geneticists and psychologists are
interested in the commonalities and variations in
our genetic makeup.
Stepping Through the Section
After you have read the section, complete the
sentences and answer the questions. As you proceed,
evaluate your performance by consulting the answers.
Do not continue with the next section until you
understand each answer. If you need to, review or
reread the section in the textbook before continuing.
1. A fundamental question in psychology deals with
the extent to which we are shaped by our heredity,
called our ______________ and by our life history,
called our ______________ .
2. The master plans for development are stored in
the ______________ . In number, each person
inherits ______________ of these structures,
______________ from each parent. Each is
composed of a coiled chain of the molecule
3. If chromosomes are the “books” of heredity, the
“words” that make each of us a distinctive human
being are called______________ . These, in turn,
are defined by pairings of four biochemical
“letters” called ______________ . The sequence of
these letters is
very different/virtually the same
from person to person.
4. The complete instructions for making an organism