Chapter 1 


An Introduction to Lifespan Development




Chapter Outline



I.        An orientation to lifespan development

A.     LIFESPAN DEVELOPMENT is the field of study that examines patterns of growth, change, and stability in behavior that occur throughout the entire lifespan.

1.      Developmental psychologists test their assumptions about the nature and course of human development by applying scientific methods.

2.      Lifespan development focuses on human development.

a)      universal principles of development

b)      cultural, racial, ethnic differences

c)      individual traits and characteristics

3.      Lifespan developmentalists view development as a lifelong, continuing process.

4.      Lifespan developmentalists focus on change and growth in addition to stability, consistency, and continuity in people's lives.

5.      Lifespan developmentalists are interested in people's lives from the moment of conception until death.

B.     Topical areas in lifespan development

1.      PHYSICAL DEVELOPMENT involves the body's physical makeup, including the brain, nervous system, muscles, and senses, and the need for food, drink, and sleep.

2.      COGNITIVE DEVELOPMENT involves the ways that growth and change in intellectual capabilities influence a person's behavior.

3.      PERSONALITY DEVELOPMENT involves the ways that the enduring characteristics that differentiate one person from another change over the lifespan.

4.      SOCIAL DEVELOPMENT is the way in which individual's interactions with others and their social relationships grow, change, and remain stable over the course of life.

C.     Age ranges and individual differences

1.      The lifespan is usually divided into broad age ranges.

a)      Prenatal period (conception to birth)

b)      Infancy and toddlerhood (birth to age 3)

c)      Preschool period (ages 3 to 6)

d)      Middle childhood (ages 6 to 12)

e)      Adolescence (ages 12 to 20)

f)       Young adulthood (ages 20 to 40)

g)      Middle adulthood (ages 40 to 60)

h)      Late adulthood (age 60 to death)

2.      It is important to remember that people mature at different rates and reach developmental milestones at different points.

3.      Environmental factors, such as one's culture, can play a significant role in determining the age at which a particular event is likely to occur.

4.      In addition, age ranges are averages and some people will show substantial deviation.

D.     The Context of Development: Taking a Broad Perspective

1.      The ECOLOGICAL APPROACH (Bronfenbrenner) is the perspective suggesting that different levels of environment simultaneously influence individuals.

a)      The microsystem is the everyday, immediate environment such as homes, caregivers, friends, teachers.

b)      The mesosystem connects various aspects of the microsystem, linking children to parents, students to teachers, employees to bosses, friends to friends.

c)      The exosystem represents such broad influences as local government, the community, schools, places of worship, and the local media.

d)      The macrosystem represents larger cultural influences such as society in general, types of government, religious systems, and political thought.

2.      There are several advantages to taking an ecological approach to development.

a)      It emphasizes the interconnectedness of the influences on development.

b)      It illustrates that influences are multidirectional.

c)      It stresses the importance of broad cultural factors that affect development.

3.      Developmental Diversity:  How Culture, Ethnicity, and Race Influence Development

a)      Developmentalists must take into consideration broad cultural factors and ethnic, racial, socioeconomic, and gender differences if they are to achieve an understanding of how people change and grow throughout the lifespan.

b)      Progress concerning issues of human diversity has been slow in the field of lifespan development.

c)      Members of the research community have sometimes used terms such as race and ethnic group in inappropriate ways.

(1)   Race is a biological concept referring to classifications based on physical and structural characteristics.

(2)   Ethnic group and ethnicity are broader terms, referring to cultural background, nationality, religion, and language.

d)      There is little agreement about which names best reflect different races and ethnic groups (i.e., African-American or black.)

e)      Race is not independent of environmental and cultural contexts.

4.      Cohort and Normative influences on Development:  Developing with Others in a Social World

a)      one's COHORT is the group of people born at around the same time and same place.

b)      NORMATIVE HISTORY-GRADED INFLUENCES are the biological and environmental influences associated with a particular historical moment.

c)      NORMATIVE AGE-GRADED INFLUENCES are biological and environmental influences that are similar for individuals in a particular age group, regardless of when or where they are raised.

d)      NORMATIVE SOCIOCULTURAL-GRADED INFLUENCES include the impact of social and cultural factors present at a particular time for a particular individual, depending on such variables as ethnicity, social class, and subcultural membership.

e)      NONNORMATIVE LIFE EVENTS are specific, atypical events that occur in a particular person's life at a time when they do not happen to most people.

E.       Key Issues and Questions:  Determining the Nature – and Nurture – of Lifespan Development

1.      Continuous Change Versus Discontinuous Change

a)      CONTINUOUS CHANGE involves gradual development in which achievements at one level build on those of previous levels.

b)      DISCONTINUOUS CHANGE is development that occurs in distinct steps or stages, with each stage bringing about behavior that is assumed to be qualitatively different from behavior at earlier stages.

2.      Critical Periods:  Gauging the Impact of Environmental Events

a)      A CRITICAL PERIOD is a specific time during development when a particular event has its greatest consequences.

b)      Because individuals are now considered more malleable than was first thought, developmentalists are more likely to speak of SENSITIVE PERIODS as a point in development when organisms are particularly susceptible to certain kinds of stimuli in their environments, but the absence of those stimuli does not always produce irreversible consequences.

3.      Lifespan Approaches Versus a Focus on Particular Periods

a)      Early developmentalists focused on "infancy" and "adolescence."

b)      Today the entire lifespan is seen as important for several reasons.

(1)   growth and change continue throughout life

(2)   an important part of every person’s environment is the other people around him or her, the person’s social environment

4.      The Relative Influence of Nature Versus Nurture on Development

a)      Nature refers to traits, abilities, and capacities that are inherited from one's parents.

(1)   It encompasses MATURATION, any factor that is produced by the predetermined unfolding of genetic information.

b)      Nurture refers to the environmental influences that shape behavior.

c)      Developmental psychologists reject the notion that behavior is the result solely of either nature or nurture.

d)      It is useful to think of the nature-nurture controversy as opposite ends of a continuum, with particular behaviors falling somewhere between the two ends.

II.                 Theoretical Perspectives

A.     THEORIES are explanations and predictions concerning phenomena of interest, providing a framework for understanding the relationships among an organized set of facts or principles.

B.     The PSYCHODYNAMIC PERSPECTIVE is the approach that states behavior is motivated by inner forces, memories, and conflicts of which a person has little awareness or control.

1.      Freud's PSYCHOANALYTIC THEORY suggests that unconscious forces act to determine personality and behavior.

a)      According to Freud (1856 - 1939),

(1)   the unconscious is a part of the personality about which a person is unaware and is responsible for much of our everyday behavior;

(2)   one's personality has three aspects:

(a)    ID, the raw, unorganized, inborn part of personality that is present at birth that represents primitive drives related to hunger, sex, aggression, and irrational impulses.

(i)     Operates according to the pleasure principle, in which the goal is to maximize satisfaction and reduce tension.

(3)   EGO, the part of personality that is rational and reasonable.

(a)    Acts as a buffer between the outside world and the                    primitive id.

(b)   Operates on the reality principle, in which instinctual energy is restrained in order to maintain the safety of the individual and help integrate the person into society.

(4)   SUPEREGO, the aspect of personality that represents a        person's conscience, incorporating distinctions between right and wrong.

(a)    Develops about age 5 or 6.

(b)   Learned from parents, teachers, and other significant figures.

b)      Freud suggested that PSYCHOSEXUAL DEVELOPMENT is a series of stages that children pass through in which pleasure, or gratification is focused on a particular biological function and body part.

(1)   Oral  (birth to 12-18 months)

(2)   Anal  (12 - 18 months to 3 years)

(3)   Phallic  (3 to 5 - 6 years)

(4)   Latency  (5 - 6 years to adolescence)

(5)   Genital  (adolescence to adulthood)

c)      If children are unable to gratify themselves sufficiently or receive too much gratification a FIXATION, behavior reflecting an earlier stage of development, may occur.

2.      Erikson's Psychosocial Theory

a)      PSYCHOSOCIAL DEVELOPMENT is the approach that encompasses changes in the understanding individuals have of both their interactions with others, and others' behavior, and of themselves as members of society.

b)      Erikson (1902 - 1994) suggested that developmental change occurs throughout our lives in eight distinct stages.

(1)   Trust vs. Mistrust  (birth to 12 - 18 months)

(2)   Autonomy vs. Shame and Doubt  (12 - 18 months to 3 years)

(3)   Initiative vs. Guilt  (3 to 5 - 6 years)

(4)   Industry vs. Inferiority  (5 - 6 years to adolescence)

(5)   Identity vs. Role diffusion  (adolescence to adulthood)

(6)   Intimacy vs. Isolation  (early adulthood)

(7)   Generativity vs. Stagnation  (middle adulthood)

(8)   Ego Integrity vs. Despair  (late adulthood)

c)      Each stage emerges in a fixed pattern and is similar for all people.

d)      Each stage presents a crisis or conflict that each individual must address sufficiently at a particular age.

e)      No crisis is ever fully resolved, which makes life increasingly complicated.

f)       Unlike Freud, Erikson believed that development continued throughout the lifespan.

3.      Assessing the Psychodynamic Perspective

a)      Contemporary psychological research supports the idea that unconscious memories have an influence on our behavior.

b)      The notion that people pass through stages in childhood that determine their adult personalities has little research support.

c)      Because Freud based his theory on a small sample of upper-middle-class Austrians living during a strict, puritanical era, it is questionable how applicable the theory is to muticultural populations.

d)      Because his theory focuses on men, it has been criticized as sexist and devaluing women.

e)      Eriksons view that development continues throughout the lifespan is highly important and has received considerable support.

f)       Erikson also focused more on men than women.

g)      Much of Erikson's theory is too vague to test rigorously.

h)      In sum, the psychodynamic perspective provides a good description of past behavior, but imprecise predictions of future behavior.

C.     The BEHAVIORAL PERSPECTIVE suggests that the keys to understanding development are observable behavior and outside stimuli in the environment.

1.      Behaviorists reject the notion that people universally pass through a series of stages.

2.      Development occurs as the result of continuing exposure to specific factors in the environment.

3.      Development is viewed as quantitative rather than qualitative.

4.      John B. Watson (1878 - 1958) argued that by effectively controlling a person's environment, it was possible to produce virtually any behavior.

5.      CLASSICAL CONDITIONING is a type of learning in which an organism responds in a particular way to a neutral stimulus that normally does not bring about that type of response.

6.      OPERANT CONDITIONING is a form of learning in which a voluntary response is strengthened or weakened, depending on its association with positive or negative consequences.

a)      B. F. Skinner (1904 - 1990) claimed that people operate on their environments to bring about a desired state of affairs.

b)      Reinforcement is the process by which a stimulus is provided that increases the probability that a preceding behavior will be repeated.

c)      Punishment, the introduction of an unpleasant or painful stimulus or the removal of a desirable stimulus, will decrease the probability that a behavior will occur in the future.

d)      When behavior receives no reinforcement it is likely to be discontinued or extinguished.

e)      Principles of operant conditioning are used in BEHAVIOR MODIFICATION, a formal technique for promoting the frequency of desirable behaviors and decreasing the incidence of unwanted ones.

7.      Albert Bandura suggests that a certain amount of learning is in the form of SOCIAL-COGNITIVE LEARNING THEORY, which is learning by observing the behavior of another person, called a model.

a)      Observer must pay attention to model's behavior.

b)      Observer must successfully recall the behavior.

c)      Behavior must be reproduced accurately.

d)      Observer must be motivated to learn and carry out behavior.

8.      Assessing the Behavioral Perspective

a)      According to classical and operant conditioning, people and organisms are black boxes in which nothing that occurs inside is understood or even cared about.

b)      Social-cognitive learning theory argues that what makes people different from rats and pigeons is mental activity which must be taken into account.

c)      Social-cognitive learning theory has come to predominate over classical and operant conditioning.

D.     The COGNITIVE PERSPECTIVE focuses on the processes that allow people to                 know, understand, and think about the world.

1.      Piaget's Theory of Cognitive Development

a)      Jean Piaget (1896 - 1980) proposed that all people pass in a fixed sequence through a series of universal stages of cognitive development.

b)      In each stage, the quantity of information increases; the quality of knowledge and understanding changes as well.

c)      Piaget suggested that human thinking is arranged into schemes, organized mental patterns that represent behaviors and actions.

d)      Piaget suggested that the growth of children's understanding of the world can be explained by two principles:

(1)   ASSIMILATION is the process in which people understand an experience in terms of their current stage of cognitive development and way of thinking.

(2)   ACCOMMODATION is the process that changes existing ways of thinking in response to encounters with new stimuli or events.

e)      Assessing Piagets Theory

(1)   thousands of investigations have shown it to be largely accurate.

(2)   Some cognitive skills emerge earlier than Piaget suggested.

(3)   Some cognitive skills emerge according to a different timetable in non-Western countries.

(a)    In every culture, some adults never reach Piaget's highest level of cognitive thought - formal, logical thought.

f)       Some developmentalists believe cognitive thought does not develop discontinuously but slowly and steadily and continuously.

2.      INFORMATION-PROCESSING APPROACHES are the model that seeks to identify the ways individuals take in, use, and store information.

a)      The theory grew out of the computer age.

b)      They assume that even complex behaviors such as learning, remembering, categorizing, and thinking can be broken down into a series of individual steps.

c)      They assume cognitive growth is more quantitative than qualitative.

d)      They suggest that as people age, they are better able to control their mental processing and change the strategies they choose to process information.

3.      Vygotsky (1896 - 1934), a Russian child developmentalist, developed            SOCIOCULTURAL THEORY, an approach that emphasizes how       cognitive development proceeds as a result of social interactions between  members of a culture.

a)      Vygotsky argued that childrens understanding of the world is acquired through their problem-solving interactions with adults and other children.

b)      He also argued that to understand the course of development we must consider what is meaningful to members of a given culture.

4.   The HUMANISTIC PERSPECTIVE contends that people have a natural capacity to make decisions about their lives and control their behavior.

c)      According to this approach, each individual has the ability and motivation to reach more advanced levels of maturity, and people naturally seek to reach their full potential.

d)      This perspective emphasizes free will, the ability of humans to make choices and come to decisions about their lives.

e)      Carl Rogers suggests that all people have a need for positive regard that results from an underlying wish to be loved and respected.

f)       Abraham Maslow suggests that self-actualization, a state of self-fulfillment in which people achieve their highest potential in their own unique way, is a primary goal in life.

g)      Assessing the Humanistic Perspective

(1)   The humanistic perspective has not had a major impact on the field of lifespan development.

(2)   It has not identified any sort of broad developmental change that is the result of age or experience.

(3)   Some criticize the theorys assumption that people are basically good, which is unverifiable.

5.      The EVOLUTIONARY PERSPECTIVES seek to identify behavior in        today’s humans that is the result of our genetic inheritance from our       ancestors.

a)      Evolutionary perspectives grew out of the work of Charles Darwin who argued in The Origin of Species that a process of natural selection creates traits in a species that are adaptive to their environment.

b)      The evolutionary perspectives argue that our genetic inheritance determines not only such physical traits as skin and eye color, but certain personality traits and social behaviors.

c)      The evolutionary perspective draws on the field of ethology (Konrad Lorenz 1903 - 1989), which examines the ways in which our biological makeup influences our behavior.

d)      The evolutionary perspective encompasses one of the fastest growing areas within the field of lifespan development: behavioral genetics, which studies the effects of heredity on behavior.

e)      Assessing the evolutionary perspectives

(1)   Some developmentalists criticize the evolutionary perspective for paying insufficient attention to the environment and social factors.

(2)   Others argue that there is no good way to support                    experimentally theories derived from evolution.

E.      Which Approach is Right?  The Wrong Question

1.      Each emphasizes different aspects of development.

2.      Psychodynamic approach emphasizes emotions, motivational conflicts, and unconscious determinants of behavior.

3.      Behavioral approaches emphasize overt behavior.

4.      Cognitive and humanist approaches look more at what people think than what they do.

5.      The evolutionary perspective focuses on how inherited biological factors underlie development.

III.               Research Methods

A.     The SCIENTIFIC METHOD is the process of posing and answering questions using careful, controlled techniques that include systematic, orderly observation and the collection of data.

1.      The scientific method involves the formulation of theories, broad explanations, and predictions about phenomena.

2.      Theories are used to develop HYPOTHESES, predictions stated in a way that permits testing.

B.     Research Strategies

1.      CORRELATIONAL RESEARCH seeks to identify whether an association or relationship between two factors exists.

a)      The strength and direction of a relationship between two factors is represented by a mathematical score, called a correlational coefficient, which ranges from +1.0 (positive) to -1.0 (negative).

(1)   A positive correlation indicates that as the value of one factor increases, it can be predicted that the value of the other will also increase.

(2)   A negative correlation informs us that as the value of one factor increases, the value of the other factor declines.

b)      Finding that two variables are correlated with one another proves nothing about causality.

c)      Types of Correlational Studies

(1)   NATURALISTIC OBSERVATION is the observation of a naturally occurring behavior without intervention in the situation.

(a)    This type of study has the advantage of seeing children in their natural habitats.

(b)   However, researchers cannot control factors of interest and may be unable to see enough behavior to draw any conclusions.

(c)    Children may know they are being watched and modify their behavior.

(d)   Naturalistic observation employs ethnography, a method borrowed from the field of anthropology and used to investigate cultural questions.

(i)     Researchers using ethnography act as participant observers, living for a period of weeks, months, or even years in another culture.

(ii)   Ethnography has the same drawbacks as other naturalistic observation in addition to the problems of generalizing from one culture to another or misinterpreting what is observed.

(2)   CASE STUDIES involve extensive, in-depth interviews with a particular individual or a small group of individuals.

(3)   SURVEY RESEARCH, where people are chosen to represent some larger population and are asked questions about their attitudes, behavior, or thinking on a given topic.

2.      Experiments:  Determining Cause and Effect

a)      An EXPERIMENT is a process in which an investigator, called an experimenter, devises two different experiences for subjects or participants.

b)      These are called TREATMENTS, procedures applied by an investigator based on two different experiences devised for participants.

c)      The group receiving the treatment is known as the TREATMENT GROUP.

d)      The CONTROL GROUP is the group that receives either no treatment or alternative treatment.

e)      The formation of treatment and control groups represents the INDEPENDENT VARIABLE, the variable that researchers manipulate in an experiment.

f)       In contrast, the DEPENDENT VARIABLE is the variable that researchers measure in an experiment and expect to change as a result of the experimental manipulation.

g)      A critical step in the design of an experiment is to assign participants to different treatment groups on the basis of chance alone, called random assignment, allowing the researcher, through laws of statistics, to draw conclusions with confidence.

h)      Choosing a Research Setting

(1)   First, researchers choose a SAMPLE, a group of participants                chosen for the experiment.

(2)   FIELD STUDY is a research investigation carried out in a naturally occurring setting.

(3)   LABORATORY STUDY is a research investigation conducted in a controlled setting explicitly designed to hold events constant.

3.      Theoretical and Applied Research

a)      THEORETICAL RESEARCH is research designed specifically to test some developmental explanation and expand scientific knowledge.

b)      APPLIED RESEARCH is research meant to provide practical solutions to immediate problems.

4.      Measuring developmental change

a)      In LONGITUDINAL RESEARCH, the behavior of one or more individuals is measured as the subjects age.

(1)   they require a tremendous investment of time

(2)   there is the possibility of participant attrition, or loss

(3)   participants may become "test-wise"

b)      In CROSS-SECTIONAL RESEARCH, people of different ages are compared at the same point in time.

(1)   differences may be due to cohort effects

(2)   selective dropout, where participants in some age groups are more likely to quit participating in the study than others.

(3)   unable to explain changes in individuals or groups

c)      In CROSS-SEQUENTIAL STUDIES, researchers examine a number of different age groups over several points in time.

(1)   combines longitudinal and cross-sectional research

(2)   can tell about age changes and age differences

5.      Ethics and Research

a)      Society for Research in Child Development and the American Psychological Association have developed ethical guidelines for researchers.

(1)   Freedom from harm

(2)   Informed consent

(3)   Use of deception

(4)   Maintenance of privacy


Key Terms and Concepts


Lifespan development

Physical development

Cognitive development

Personality development

Social development

Ecological approach


Normative history-graded influences

Normative age-graded influences

Normative sociocultural-graded influences

Nonnormative life events

Continuous change

Discontinuous change

Critical period

Sensitive period



Psychodynamic perspective

Psychoanalytic theory




Psychosexual development


Psychosocial development

Behavioral perspective

Classical conditioning

Operant conditioning

Behavior modification

Social-cognitive learning theory

Cognitive perspective



Information processing approaches

Sociocultural theory

Humanistic theory

Evolutionary perspective

Scientific method


Correlational research

Experimental research

Naturalistic observation

Case studies

Survey research



Treatment group

Control group

Independent variable

Dependent variable


Field study

Laboratory study

Theoretical research

Applied research

Longitudinal research

Cross-sectional research

Cross-sequential studies