Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
Instructor Manual
Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026
Chapter 1: History, Theories, and Methods
TABLE OF CONTENTS
Purpose and Perspective of the Chapter......................................................................2
Learning Objectives.......................................................................................................2
Key Terms.....................................................................................................................2
What's New in This Chapter........................................................................................7
Chapter Outline.............................................................................................................8
Additional Activities and Assignments.......................................................................15
Lecture Expanders................................................................................................................................... 15
Classroom Activities................................................................................................................................17
Student Project Suggestions.....................................................................................................................19
Additional Resources..................................................................................................21
Videos...................................................................................................................................................... 21
Internet Resources....................................................................................................................................22
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 1
publicly accessible website, in whole or in part.
, Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
PURPOSE AND PERSPECTIVE OF THE CHAPTER
This chapter provides the general introduction to the history of child development, beginning with a
definition of child development and a discussion of the purposes and goals of theory and research in the
field. After a brief survey of the leaders in the field of developmental psychology, each of the major
theories and perspectives of child development is described and evaluated: psychoanalytic, learning,
cognitive, biological, ecological, and sociocultural. Next, the nature–nurture, continuity–discontinuity,
and active–passive controversies in the field are reviewed. Research methods are then described,
including an overview of the scientific method, research methods of gathering information in child
developmental science, the correlational method (and its limitations), and how to approach and design
experiments. The chapter ends with a look at the special methods needed to ask questions about
development over time (longitudinal versus cross-sectional research) and a discussion of specific ethical
issues that should be considered when conducting research with children.
LEARNING OBJECTIVES
The following objectives are addressed in this chapter:
1-1 Define child development, explain why researchers study child development, and describe the
history of the study of child development.
1-2 Describe and evaluate theories of child development, including psychoanalytic theory,
learning theories, cognitive-developmental theory, biological views, ecological systems
theory, and the sociocultural perspective.
1-3 Discuss controversies in child development, including the nature–nurture controversy,
whether development is continuous or discontinuous, and whether children are active or
passive participants in their development.
1-4 Explain how researchers study child development, referring to the scientific method, methods
of observation, the correlational method, the experiment, and longitudinal versus cross-
sectional studies.
1-5 Discuss ethical considerations in the study of child development.
KEY TERMS
accommodation: According to Piaget, the modification of existing schemes to permit the
incorporation of new events or knowledge.
adaptation: According to Piaget, an interaction between the organism and the environment that
consists of two processes: assimilation and accommodation.
assimilation: According to Piaget, the incorporation of new events or knowledge into existing
schemes.
behaviorism: John B. Watson’s view that a science or theory of development must study observable
behavior only and investigate relationships between stimuli and responses.
case study: A carefully drawn biography of the life of an individual.
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 2
publicly accessible website, in whole or in part.
, Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
child: A person undergoing the period of development from infancy through puberty.
chronosystem: The environmental changes that occur over time and have an impact on the child (from
the Greek chronos, meaning “time”).
classical conditioning: A simple form of learning in which one stimulus comes to bring forth the
response usually elicited by a second stimulus by being paired repeatedly with the second stimulus.
cognitive-developmental theory: The stage theory that holds that the child’s abilities to mentally
represent the world and solve problems unfold as a result of the interaction of experience and the
maturation of neurological structures.
cohort effect: Similarities in behavior among a group of peers that stem from the fact that group
members are approximately the same age.
control group: A group made up of subjects in an experiment who do not receive the treatment but for
whom all other conditions are comparable to those of subjects in the experimental group.
correlation: A relationship between variables in which one variable increases as a second variable also
increases (a positive correlation) or decreases (a negative correlation).
correlation coefficient: A number ranging from −1.00 to +1.00 that expresses the direction (positive
or negative) and strength of the relationship between two variables.
cross-sectional research: The study of developmental processes by taking measures of children of
different age groups at the same time.
cross-sequential research: An approach that combines the longitudinal and cross-sectional methods
by following individuals of different ages for abbreviated periods of time.
dependent variable: In a scientific study, a measure of an assumed effect of an independent variable.
development: The processes by which organisms unfold features and traits, grow, and become more
complex and specialized in structure and function.
ecological systems theory: The view that explains child development in terms of the reciprocal
influences between children and the settings that make up their environment.
ecology: The branch of biology that deals with the relationships between living organisms and their
environment.
empirical: Based on observation and experimentation.
equilibration: The creation of an equilibrium, or balance, between assimilation and accommodation as
a way of incorporating new events or knowledge.
ethnic groups: Groups of people distinguished by their cultural heritage, race, language, and common
history.
ethology: The study of behaviors that are specific to a species—how these behaviors evolved, help the
organism adapt, and develop during critical periods.
exosystem: Community institutions and settings that indirectly influence the child, such as the school
board and the parents’ workplaces (from the Greek exo, meaning “outside”).
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 3
publicly accessible website, in whole or in part.
, Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
experiment: A method of scientific investigation that seeks to discover cause-and-effect relationships
by introducing independent variables and observing their effects on dependent variables.
experimental group: A group made up of subjects who receive a treatment in an experiment.
gender diverse: Noting or relating to a person whose gender identity or gender expression does not
conform to socially defined male or female gender norms.
genes: The basic building blocks of heredity. Genes are composed of deoxyribonucleic acid (DNA).
growth: The processes by which organisms increase in size, weight, strength, and other traits as they
develop.
hypothesis: A specific statement about behavior that is tested by research.
identity crisis: According to Erikson, an adolescent period of inner conflict during which one
examines one’s values and makes decisions about one’s life roles.
imprinting: The process by which some animals exhibit the fixed action pattern (FAP) of attachment
in response to a releasing stimulus. The FAP occurs during a critical period and is difficult to modify.
independent variable: In a scientific study, the condition that is manipulated (changed) so that its
effects can be observed.
infancy: The period of very early childhood, characterized by lack of complex speech; the first 2 years
after birth.
Information-processing theory: A cognitive theory that focuses on how information is encoded in
people’s memory, how it is stored or kept in working memory, and how it is retrieved from memory
life crisis: An internal conflict that attends each stage of psychosocial development. Positive resolution
of early life crises sets the stage for positive resolution of subsequent life crises.
longitudinal research: The study of developmental processes by taking repeated measures of the
same group of children at various stages of development.
macrosystem: The basic institutions and ideologies that influence the child, such as the American
ideals of freedom of expression and equality under the law (from the Greek makros, meaning “long” or
“enlarged”).
mesosystem: The interlocking settings that influence the child, such as the interaction of the school and
the larger community when children are taken on field trips (from the Greek mesos, meaning “middle”).
meta-analysis: A method of analyzing, or averaging, the results of multiple research studies.
microsystem: The immediate settings with which the child interacts, such as the home, the school, and
the child’s peers (from the Greek mikros, meaning “small”).
naturalistic observation: A method of scientific observation in which children (and others) are
observed in their natural environments.
nature: The processes within an organism that guide that organism to develop according to its genetic
code.
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 4
publicly accessible website, in whole or in part.
Methods
Instructor Manual
Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026
Chapter 1: History, Theories, and Methods
TABLE OF CONTENTS
Purpose and Perspective of the Chapter......................................................................2
Learning Objectives.......................................................................................................2
Key Terms.....................................................................................................................2
What's New in This Chapter........................................................................................7
Chapter Outline.............................................................................................................8
Additional Activities and Assignments.......................................................................15
Lecture Expanders................................................................................................................................... 15
Classroom Activities................................................................................................................................17
Student Project Suggestions.....................................................................................................................19
Additional Resources..................................................................................................21
Videos...................................................................................................................................................... 21
Internet Resources....................................................................................................................................22
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 1
publicly accessible website, in whole or in part.
, Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
PURPOSE AND PERSPECTIVE OF THE CHAPTER
This chapter provides the general introduction to the history of child development, beginning with a
definition of child development and a discussion of the purposes and goals of theory and research in the
field. After a brief survey of the leaders in the field of developmental psychology, each of the major
theories and perspectives of child development is described and evaluated: psychoanalytic, learning,
cognitive, biological, ecological, and sociocultural. Next, the nature–nurture, continuity–discontinuity,
and active–passive controversies in the field are reviewed. Research methods are then described,
including an overview of the scientific method, research methods of gathering information in child
developmental science, the correlational method (and its limitations), and how to approach and design
experiments. The chapter ends with a look at the special methods needed to ask questions about
development over time (longitudinal versus cross-sectional research) and a discussion of specific ethical
issues that should be considered when conducting research with children.
LEARNING OBJECTIVES
The following objectives are addressed in this chapter:
1-1 Define child development, explain why researchers study child development, and describe the
history of the study of child development.
1-2 Describe and evaluate theories of child development, including psychoanalytic theory,
learning theories, cognitive-developmental theory, biological views, ecological systems
theory, and the sociocultural perspective.
1-3 Discuss controversies in child development, including the nature–nurture controversy,
whether development is continuous or discontinuous, and whether children are active or
passive participants in their development.
1-4 Explain how researchers study child development, referring to the scientific method, methods
of observation, the correlational method, the experiment, and longitudinal versus cross-
sectional studies.
1-5 Discuss ethical considerations in the study of child development.
KEY TERMS
accommodation: According to Piaget, the modification of existing schemes to permit the
incorporation of new events or knowledge.
adaptation: According to Piaget, an interaction between the organism and the environment that
consists of two processes: assimilation and accommodation.
assimilation: According to Piaget, the incorporation of new events or knowledge into existing
schemes.
behaviorism: John B. Watson’s view that a science or theory of development must study observable
behavior only and investigate relationships between stimuli and responses.
case study: A carefully drawn biography of the life of an individual.
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 2
publicly accessible website, in whole or in part.
, Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
child: A person undergoing the period of development from infancy through puberty.
chronosystem: The environmental changes that occur over time and have an impact on the child (from
the Greek chronos, meaning “time”).
classical conditioning: A simple form of learning in which one stimulus comes to bring forth the
response usually elicited by a second stimulus by being paired repeatedly with the second stimulus.
cognitive-developmental theory: The stage theory that holds that the child’s abilities to mentally
represent the world and solve problems unfold as a result of the interaction of experience and the
maturation of neurological structures.
cohort effect: Similarities in behavior among a group of peers that stem from the fact that group
members are approximately the same age.
control group: A group made up of subjects in an experiment who do not receive the treatment but for
whom all other conditions are comparable to those of subjects in the experimental group.
correlation: A relationship between variables in which one variable increases as a second variable also
increases (a positive correlation) or decreases (a negative correlation).
correlation coefficient: A number ranging from −1.00 to +1.00 that expresses the direction (positive
or negative) and strength of the relationship between two variables.
cross-sectional research: The study of developmental processes by taking measures of children of
different age groups at the same time.
cross-sequential research: An approach that combines the longitudinal and cross-sectional methods
by following individuals of different ages for abbreviated periods of time.
dependent variable: In a scientific study, a measure of an assumed effect of an independent variable.
development: The processes by which organisms unfold features and traits, grow, and become more
complex and specialized in structure and function.
ecological systems theory: The view that explains child development in terms of the reciprocal
influences between children and the settings that make up their environment.
ecology: The branch of biology that deals with the relationships between living organisms and their
environment.
empirical: Based on observation and experimentation.
equilibration: The creation of an equilibrium, or balance, between assimilation and accommodation as
a way of incorporating new events or knowledge.
ethnic groups: Groups of people distinguished by their cultural heritage, race, language, and common
history.
ethology: The study of behaviors that are specific to a species—how these behaviors evolved, help the
organism adapt, and develop during critical periods.
exosystem: Community institutions and settings that indirectly influence the child, such as the school
board and the parents’ workplaces (from the Greek exo, meaning “outside”).
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 3
publicly accessible website, in whole or in part.
, Instructor Manual: Rathus/Rathus, Childhood and Adolescence: Voyages in Development, 8th Edition ©2026 Chapter 1: History, Theories, and
Methods
experiment: A method of scientific investigation that seeks to discover cause-and-effect relationships
by introducing independent variables and observing their effects on dependent variables.
experimental group: A group made up of subjects who receive a treatment in an experiment.
gender diverse: Noting or relating to a person whose gender identity or gender expression does not
conform to socially defined male or female gender norms.
genes: The basic building blocks of heredity. Genes are composed of deoxyribonucleic acid (DNA).
growth: The processes by which organisms increase in size, weight, strength, and other traits as they
develop.
hypothesis: A specific statement about behavior that is tested by research.
identity crisis: According to Erikson, an adolescent period of inner conflict during which one
examines one’s values and makes decisions about one’s life roles.
imprinting: The process by which some animals exhibit the fixed action pattern (FAP) of attachment
in response to a releasing stimulus. The FAP occurs during a critical period and is difficult to modify.
independent variable: In a scientific study, the condition that is manipulated (changed) so that its
effects can be observed.
infancy: The period of very early childhood, characterized by lack of complex speech; the first 2 years
after birth.
Information-processing theory: A cognitive theory that focuses on how information is encoded in
people’s memory, how it is stored or kept in working memory, and how it is retrieved from memory
life crisis: An internal conflict that attends each stage of psychosocial development. Positive resolution
of early life crises sets the stage for positive resolution of subsequent life crises.
longitudinal research: The study of developmental processes by taking repeated measures of the
same group of children at various stages of development.
macrosystem: The basic institutions and ideologies that influence the child, such as the American
ideals of freedom of expression and equality under the law (from the Greek makros, meaning “long” or
“enlarged”).
mesosystem: The interlocking settings that influence the child, such as the interaction of the school and
the larger community when children are taken on field trips (from the Greek mesos, meaning “middle”).
meta-analysis: A method of analyzing, or averaging, the results of multiple research studies.
microsystem: The immediate settings with which the child interacts, such as the home, the school, and
the child’s peers (from the Greek mikros, meaning “small”).
naturalistic observation: A method of scientific observation in which children (and others) are
observed in their natural environments.
nature: The processes within an organism that guide that organism to develop according to its genetic
code.
© 2026 Cengage Learning, Inc. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a 4
publicly accessible website, in whole or in part.
