As you read earlier in this chapter, the scientific method begins with observations, questions, and theories (Step 1). That leads to specific hypotheses that can be tested (Step 2). A theory is a comprehensive and organized explanation of many phenomena; a hypothesis is more limited and may be proven false. Theories are generalities; hypotheses are specific.

Theories sharpen perceptions and organize the thousands of behaviors we observe every day. Each developmental theory is a systematic statement of principles and generalizations, providing a framework for understanding how and why people change over the life span.

Imagine building a house from a heap of lumber, nails, and other materials. Without a plan and workers, the heap cannot become a home. Likewise, observations of human development are raw materials, but theories put them together. Kurt Lewin (1943) once quipped, “Nothing is as practical as a good theory.”

Dozens of such theories appear throughout this text. The five theories about to be explained are chosen because each provides a comprehensive, influential, and somewhat distinctive view of human development. Many social scientists are strongly influenced by other theories, as you will see.

Inner drives and motives are the foundation of psychoanalytic theory. These basic underlying forces are thought to influence every aspect of thinking and behavior, from the smallest details of daily life to the crucial choices of a lifetime.

24

FREUD’S STAGES Psychoanalytic theory originated with Sigmund Freud (1856–1939), an Austrian physician who treated patients suffering from mental illness. He listened to their dreams and fantasies and constructed an elaborate, multifaceted theory.

According to Freud, development in the first six years occurs in three stages, each characterized by sexual pleasure centered on a particular part of the body. Infants experience the oral stage because their erotic body part is the mouth, followed by the anal stage in early childhood, with the focus on the anus. In the preschool years (the phallic stage), the penis becomes a source of pride and fear for boys and a reason for sadness and envy for girls.

In middle childhood comes latency, a quiet period that ends with the genital stage at puberty. Freud thought that the genital stage continued throughout adulthood, which makes him the most famous theorist who thought that development stopped after puberty (see Table 1.4). As you remember, this assumption is no longer held by developmentalists.

Freud maintained that at each stage, sensual satisfaction (from the mouth, anus, or genitals) is linked to developmental needs, challenges, and conflicts. How people experience and resolve these conflicts—especially those related to weaning (oral), toilet training (anal), male roles (phallic), and sexual pleasure (genital)—determines personality patterns because “the early stages provide the foundation for adult behavior” (Salkind, 2004, p. 125).

ERIKSON’S STAGES Many of Freud’s followers became famous theorists themselves. The most notable for our study of human development was Erik Erikson (1902–1994), who described eight developmental stages, each characterized by a challenging crisis (summarized in Table 1.4). Although Erikson’s first five stages build on Freud’s theory, he also described three adult stages, perhaps because he saw himself changed with several adult shifts in context. He was a wandering artist in Italy, a teacher in Austria, and a Harvard professor in the United States.

25

Erikson named two polarities at each stage (which is why the word versus is used in each), but he recognized that many outcomes between these opposites are possible (Erikson, 1993). For most people, development at each stage leads to neither extreme.

For instance, the generativity-versus-stagnation stage of adulthood rarely involves a person who is totally stagnant—no children, no work, no creativity. Instead, most adults are somewhat stagnant and somewhat generative. As the dynamic-systems theory would predict, the balance may shift year by year.

Erikson, like Freud, believed that adult problems echo childhood conflicts. For example, an adult who cannot form a secure, close relationship (intimacy versus isolation) may not have resolved the crisis of infancy (trust versus mistrust). However, Erikson’s stages differ significantly from Freud’s in that they emphasize family and culture, not sexual urges. He called his theory epigenetic, partly to stress that genes and biological impulses are powerfully influenced by the social environment.

26

Another influential theory, behaviorism, arose in direct opposition to the psychoanalytic emphasis on unconscious, hidden urges (differences are described in Table 1.5). Behaviorists emphasize nurture, the specific responses from other people and the environment to whatever a developing person does.

WATSON Early in the twentieth century, John B. Watson (1878–1958) argued that scientists should examine only what they could observe and measure. According to Watson, if psychologists focus on behavior, they will realize that anything can be learned. For this reason, behaviorism is also called learning theory. Watson wrote:

Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select—doctor, lawyer, artist, merchant chief, and yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race.

[Watson, 1998, p. 82]

Many other psychologists, especially in the United States, agreed. They found that the unconscious motives and drives that Freud described were difficult (or impossible) to verify via the scientific method (Uttal, 2000). For instance, researchers discovered that, contrary to Freud’s view, the parents’ approach to toilet training did not determine a child’s later personality.

For every individual at every age, from newborn to centenarian, behaviorists have identified laws to describe how environmental responses shape what people do. All behavior—from reading a book to robbing a bank, from saying “Good morning” to a stranger to saying “I love you” to a spouse—follows these laws. Every action is learned, step by step.

PAVLOV The specific laws of learning apply to conditioning, the processes by which responses become linked to particular stimuli.

27

More than a century ago, Ivan Pavlov (1849–1936), a Russian medical doctor born in poverty who won a Nobel Prize for his work on digestion, noticed something in his experimental dogs that awakened his curiosity (Step 1 of the scientific method) (Todes, 2014). The dogs drooled not only when they saw and smelled food but also when they heard the footsteps of the attendants who brought the food. This observation led Pavlov to hypotheses and experiments in which he conditioned dogs to salivate when they heard a specific noise (Steps 2 and 3).

Pavlov began by sounding a tone just before presenting food. After a number of repetitions of the tone-then-food sequence, dogs began salivating at the sound, even when there was no food. This simple experiment demonstrated classical conditioning, when a person or animal learns to associate a neutral stimulus (the sound) with a meaningful stimulus (the food), gradually reacting to the neutral stimulus in the same way as to the meaningful one (Step 4). The fact that Pavlov published (Step 5) in Russian is one reason his research took decades to reach the United States (Todes, 2014).

SKINNER One influential North American behaviorist, B. F. Skinner (1904–1990), was inspired by Pavlov (1953). Skinner agreed that classical conditioning explains some behavior. Then he went further, experimenting to demonstrate another type of conditioning, operant conditioning.

In operant conditioning (also called instrumental conditioning), animals (including humans) perform some action and then a response occurs. If the response is useful or pleasurable, the animal is likely to repeat the action; if the response is painful, the animal is not likely to repeat the action. In both cases, the animal has learned.

Pleasant consequences are sometimes called rewards, and unpleasant consequences are sometimes called punishments. Behaviorists hesitate to use those words, however, because what people think of as punishment can actually be a reward, and vice versa.

For example, how should a parent punish a child? Withholding dessert? Spanking? Not letting them play? Speaking harshly? If a child hates that dessert, being deprived of it is actually a reward, not a punishment. Another child might not mind a spanking, especially if he or she craves parental attention. For that child, the intended punishment (spanking) is actually a reward (attention).

Any consequence that follows a behavior and makes the person (or animal) likely to repeat that behavior is called a reinforcement, not a reward. Once a behavior has been conditioned, humans and other creatures will repeat it even if reinforcement occurs only occasionally. Similarly, an unpleasant response makes a creature less likely to repeat a certain action.

28

Almost all daily behavior, from combing your hair to joking with friends, is a result of past operant conditioning, according to behaviorists. Likewise, things people fear, from giving a speech to eating raw fish, are avoided because of past punishment.

This insight has many practical applications for human development. Early responses are crucial because children learn habits that endure. For instance, if parents want their child to share, and their baby offers them a gummy, half-eaten cracker, they should take the gift with apparent delight and then return it, smiling.

According to behaviorism, people are never too old to learn. If an adult is afraid of speaking in public (a particular kind of social phobia, very common), then repeated reinforcement for talking (such as a professor praising a student’s question) could eventually lead to speeches before an audience.

BANDURA A major extension of behaviorism is social learning theory, first described by Albert Bandura (b. 1925). This theory notes that, because humans are social beings, they learn from observing others, even without personally receiving any reinforcement (Bandura, 1977; 2006).

For example, many studies find that most children who witness domestic violence are influenced by it. As differential susceptibility and multi-contextualism would predict, the particular lesson learned depends on each individual’s genes and experiences. For instance, if their father often hit their mother, one son might identify with the abuser and another with the victim, perhaps because of how their mother cared for them when they were infants.

Later in adulthood, because of their past social learning, one man might slap his wife and spank his children, while his brother might be fearful and apologetic at home. Social learning taught them opposite lessons. A third brother might be more like a dandelion than an orchid, unaffected by past memories.

In cognitive theory, each person’s ideas and beliefs are crucial. This theory has dominated psychology since about 1980 and has branched into many versions. The word cognitive refers not just to thinking but also to attitudes, beliefs, and assumptions.

The most famous cognitive theorist was Jean Piaget (1896–1980). Unlike other scientists of the early twentieth century, Piaget realized that babies are curious and thoughtful, creating their own interpretations about their world. He began by observing his own three infants; later he studied thousands of older children (Inhelder & Piaget, 1958/2013b).

29

From this work, Piaget developed the central thesis of cognitive theory: How people think (not just what they know) changes with time and experience, and then human thinking influences actions. Piaget maintained that cognitive development occurs in four major age-related periods, or stages: sensorimotor, preoperational, concrete operational, and formal operational (see Table 1.6).

Intellectual advancement occurs lifelong because humans seek cognitive equilibrium, that is, a state of mental balance. An easy way (called assimilation) to achieve this balance is to interpret new experiences through the lens of preexisting ideas. For example, infants discover that new objects can be grasped in the same way as familiar objects; adolescents explain the day’s headlines as evidence that supports their existing worldviews; older adults speak fondly of the good old days as embodying values that should endure.

Sometimes, however, a new experience is jarring and incomprehensible. The resulting experience is one of cognitive disequilibrium, an imbalance that initially creates confusion. As Figure 1.10 illustrates, disequilibrium leads to cognitive growth because it forces people to adapt their old concepts (called accommodation). Current research supports the idea that learning is more likely to occur if it took some effort to achieve (Brown et al., 2014).

32

Another influential cognitive theory, called information processing, is not a stage theory but rather provides a detailed description of the steps of cognition, with attention to perceptual and neurological processes. This theory is especially useful in understanding thinking processes in middle childhood and late adulthood, as you will see in Chapters 7 and 14.

Many researchers, in addition to those influenced by information-processing theory, now think that some of Piaget’s conclusions were mistaken. However, every developmentalist appreciates Piaget’s basic insight: Thoughts can influence emotions and actions. People of all ages construct their understanding of themselves and their world, combining their experiences and their interpretations.

Many scientists are convinced that there is something hopeful, unifying, and noble in the human spirit, something often ignored by psychoanalytic theory and by behaviorism. The limits of those two major theories were especially apparent to Abraham Maslow (1908–1970), one of the founders of the psychological theory of humanism. Maslow believed that all people—no matter what their culture, gender, or background—have the same basic needs and drives. He arranged these needs in a hierarchy (see Figure 1.11):

At the final level, self-actualization, when all other needs have been met, people can be fully themselves—creative, spiritual, curious, appreciative of nature, able to respect everyone else. The person has “peak experiences” when life is so intensely joyful that time stops and self-seeking disappears (Maslow, 1962/1998).

Maslow contended that everyone must satisfy each lower level before moving higher. A starving man, for instance, may risk his life to secure food (level 1 precedes level 2), or an unloved woman might not care about self-respect because she needs affection (level 3 precedes level 4). People may be destructive and inhumane, not self-actualizing, because of unmet lower needs.

33

Although humanism does not postulate stages, a developmental application of this theory is that satisfying childhood needs allows later growth. Thus, when babies cry in hunger, someone should feed them because their basic needs (level 1) should be met. People may become thieves or even killers, unable to reach their potential, if they were unsafe (level 2) or unloved (level 3) as children.

This theory is prominent among medical professionals because they realize that pain can be physical (the first two levels) or social (the next two), and they are concerned that their focus on physical health might overlook the person’s higher needs (Brown et al., 2014).

A practicing general practitioner writes that Maslow’s hierarchy is “a useful reference tool,” although he accepts that most of what doctors do is at the lower levels of the pyramid (Dawlatly, 2014). Even the dying need love and belonging (family should be with them) and esteem (the dying need respect).

30

Charles Darwin’s basic ideas about evolution were first published 150 years ago (Darwin, 1859), but serious research on human development inspired by evolutionary theory is quite recent. According to this theory, nature works to ensure that each species does two things: survive and reproduce. Consequently, many human impulses, needs, and behaviors evolved to help humans survive and thrive over the past 100,000 years (Konner, 2010).

To understand human development, this theory contends, one needs to recognize what was adaptive thousands of years ago. For example, it is irrational that many people are terrified of snakes (which now cause less than one U.S. death in a million), but virtually no one fears automobiles (which cause more than one death in a hundred). Evolutionary theory suggests that the fear instinct evolved to protect life when snakes killed many people, which was true until quite recently in the history of our species. Fears have not caught up to modern life.

34

Some of the best human qualities, such as cooperation, spirituality, and self-sacrifice, may have originated thousands of years ago, when groups of people survived because they took care of one another. Childhood itself, particularly the long period when children depend on others while their brains grow, can be explained via evolution (Konner, 2010).

One fact that evolutionary theory can explain is that human mothers welcome child-raising help from fathers, other relatives, and even strangers. Shared child rearing allows women to have children every two years or so, unlike chimpanzees, who space births four or five years apart (Hrdy, 2009). The reason, according to this theory, is the need for survival and reproduction. The result: seven billion humans alive today, but about two hundred thousand chimpanzees, a ratio of 35,000 to one.

Evolutionary theory in developmental psychology has intriguing explanations for many phenomena: women’s nausea in pregnancy; 1-year-olds’ attachment to their parents; adolescent rebellion; emerging adults’ sexual preferences; parents’ investment in their children; and late adulthood increases in major neurocognitive disorder and cancer.

All these interpretations are controversial. The influence of nature versus nurture on male/female differences is particularly controversial and provocative (Chapman, 2015). Nonetheless, this theory provides many hypotheses to be explored.

WHAT HAVE YOU LEARNED?

Question 1.22

In Freud’s theory, our unconscious drives and motives influence every aspect of our thinking and behavior.

Question 1.23

Oral (birth to 1 year); anal (1 to 3 years); phallic (3 to 6 years); latency (6 to 11 years); genital (adolescence); and adulthood

Question 1.24

Erikson’s stages differ significantly from Freud’s in that they emphasize family and culture, not sexual urges.

Question 1.25

Behaviorism arose in direct opposition to the psychoanalytic emphasis on unconscious, hidden urges. Behaviorists emphasize nurture, the specific, observable responses from other people and the environment to whatever a developing person does.

Question 1.26

In classical conditioning, one stimulus may be associated with another (tone-then-food sequence with Pavlov’s dogs). With operant conditioning, reinforcement and punishment may guide future behavior.

Question 1.27

The social learning theory is a major extension of behaviorism because it argues that humans are social beings—they learn from observation without personally receiving any reinforcement.

Question 1.28

Cognitive theory focuses on changes in how people think over time. According to this theory, thoughts shape attitudes, beliefs, and behaviors.

Question 1.29

Unlike Piaget’s stage theory, information processing provides a detailed description of the steps of cognition, with attention to perceptual and neurological processes.

Question 1.30

Physiological (needing food, water, warmth, and air); safety (feeling protected from injury and death); love and belonging (having loving friends, family, and a community); esteem (being respected by the wider community as well as by oneself); and self-actualization (becoming truly oneself, fulfilling one’s unique potential).

Question 1.31

Medical professionals realize that pain can be physical (the first two levels) or social (the next two), and they are aware that their focus on physical health might overlook the person’s higher needs.

Question 1.32

Evolutionary theory contends that to understand human development, one needs to recognize what was adaptive thousands of years ago. Some of the best human qualities, such as cooperation, spirituality, and self-sacrifice, may have originated thousands of years ago, when groups of people survived because they took care of one another.