PSY5130 Week 1 Journal

Learning Objectives

After completing this chapter, you should be able to:

Identify and describe major categories of psychological theories and their collective contributions to psychology.

Describe the main considerations of the empirical research process.

Explain the use of descriptive research and identify limitations.

Summarize the different approaches for studying change over time and identify limitations.

Explain the purpose of the experimental method and describe how relationships are identi�ied.

Explain why it is important to critically analyze research conclusions.

2Foundational Theories and Research Practicesin the Study of Human Development

iStock/Thinkstock

Prologue

One of the most fundamental—and fascinating—questions in psychology concerns how we all grow up to be so different. Blanca and Roberta, two sisters I know well, grew up in a two-parent, middle-class family. Though they were born less than two years apart, they developed into two very different people. Older sister Blanca is sel�ish, mean- spirited, insecure, and somewhat lazy. She never reached her potential either academically or in her career, usually accepting defeat without much of a �ight. She had dif�icult relationships with both her spouse and her extended family, �inally becoming estranged from most of the family she grew up with. After graduating college, she had various jobs that allowed her to remain stagnant, which re�lected her personality. Blanca was �ired from several professional positions when she did not meet expectations for advancement. But she later landed a position in the local government that was consistent with her tendency to do minimal work. She did not strive for promotions or professional excellence and remains at the same organization 20 years later.

Blanca’s younger sister Roberta took a completely different path. She was more independent than Blanca, competitive, con�ident, excelled in school, and worked hard to become a top doctor. She said she had learned from her older sister’s shortcomings and vowed to be kinder, more giving, and use more of her potential than her sister had done. She appears to have succeeded. In contrast to Blanca, Roberta is close to her extended family members, who often look to her for support and guidance. She is well respected professionally and socially active.

How might we explain the wide personality and behavioral differences exhibited by Blanca and Roberta? Though there is no perfect answer, our responses to this type of question depend a lot on how we view human development and psychological theories. Sigmund Freud might say that speci�ic early psychosexual con�licts in the lives of each sister determined their behavior; Erik Erikson would transform Freud’s view and emphasize that a series of social experiences determined how they developed as individuals. Behaviorists, like B. F. Skinner, would counter that speci�ic behaviors had been reinforced or ignored, while Albert Bandura would supplement Skinner’s view and say that what each girl had observed is also essential to understanding behavior. Still other perspectives emphasize additional aspects of cognition and behavior. Because of the many different ways that development is thought to occur, this chapter will �irst focus on these different theoretical perspectives. Then, we will outline the scienti�ic processes involved in testing our assumptions about potential developmental differences.

Science and Society/Superstock

Freud believed that children pass through �ive stages of psychosexual development: the

2.1 Theoretical Foundations: Major Perspectives of Human Development

Scienti�ic study in general endeavors to describe, predict, and explain events. The scienti�ic study of lifespan development is no different. We want to scienti�ically identify the changes that occur during the lifespan and then understand how those changes come about. Ideally, we want to be able to use knowledge gained from scienti�ic study and apply it in a way that will improve people’s functioning. For example, we might want to know how the small, incremental changes in language occur that eventually develop into that which most of us take for granted—talking. If we can identify what changes occur and then the processes behind them, we can more easily design interventions to improve language development and identify problems in that area early on.

Before we attempt to predict changes in development, we must formulate general principles on how those changes occur. Without some accepted principle, or theory, behavior would simply be recorded without a real explanation for what is happening. Theory is necessary to guide observations. For example, developmentalists want to understand how language development is affected by experience. But, we also want to learn how language appears naturally even in the absence of certain kinds of experiences. What accounts for so much variation in language ability? We need to have a theoretical framework through which to ask this kind of question.

By developing a theory that language occurs as a result of normal brain maturation, we can study the effects of differing amounts of exposure to words on language development. If we learn language regardless of our exposure to many or to few words, there must be some biological mechanism that forces language to emerge. Understanding the emergence of language in childhood may help us understand how to treat the loss of language that sometimes occurs with brain trauma or stroke. So constructing a theory allows scientists to consider different processes that might affect the path of development. Next, theories are tested. Finally, conclusions can be used to design intervention strategies in homes, schools, hospitals, and other treatment facilities.

To fully understand lifespan development, we must evaluate some of the accepted theories that have historically provided a foundation for study. In the same way that we use different senses to identify objects in our environment, the diverse perspectives presented here allow us to focus on widely accepted tenets of lifespan development. With time and research, these theories have been expanded, modi�ied, and in some cases, largely fallen out of favor. For instance, the multidisciplinary approach to psychological research and theory allowed psychologists to understand that homosexuality is one of many normal developmental trajectories, though prior to 1974 it was considered abnormal (Spitzer, 1981). Unlike physical sciences that often reach de�initive conclusions, the understanding of psychological processes is often in a state of �lux. Over time, studies will both solidify some older theories and generate new ones.

Sigmund Freud and Psychoanalytic Theory

Sigmund Freud (1856–1939) remains the most well-known �igure in the modern study of psychology. According to his psychoanalytic theory, we are born with an instinctual sexual drive that later becomes the source of anxiety and maladaptive behavior. According to Freud, children progress through �ive stages of psychosexual development. Each stage is focused on a particular body part or function. For instance, the mouth is the central source of pleasure for the newborn. Infants can be observed putting everything into their mouths; they receive pleasure through contact with a nipple or food. Therefore, Freud called this initial stage of development the oral stage. In years 2 and 3, children shift their focus of pleasure from the mouth to the anus. They learn to postpone immediate grati�ication by learning to use the toilet. Hence, Freud called this the anal stage.

During the phallic (resembling a penis) stage from about 3 to 6 years, children’s grati�ication is centered on discovering their bodies. Freud would say that “playing doctor” and undressing with other children would satisfy the developmental imperative to understand the genital differences between boys and girls. During the latency (hidden) stage from about age 6 to 12, children repress their sexual urges. Instinctual sexual drives are transformed into energy for school, friendships, and favorite activities. Freud’s fourth and last stage, the

oral stage, the anal stage, the phallic stage, the latency stage, and the genital stage.

genital stage, lasts from puberty into adulthood. Here, sexual curiosity becomes more adult-like. Instead of being motivated strictly by instinctual drives, the mature adolescent becomes thoughtful. This cognitive intervention delays personal, solitary grati�ication in order to pursue meaningful sexual relationships.

When grati�ication is denied or frustration ensues at any of the stages, anxiety results. Inadequate opportunities most often cause a �ixation, or preoccupation with a particular psychosexual element. For example, according to Freud, babies who receive inadequate warmth and closeness due to a lack of breastfeeding might develop an oral �ixation. He said that maladjustment would be displayed as a preoccupation with cigarettes, eating, oral sex, or other activities that focus on the mouth. A �ixation at the anal stage would result in obsessive orderliness and attention to detail, or hoarding behavior (hoarding is analogous to the control of bowels, since they both involve retention). In contrast, children develop into well-adjusted adults with mature sexual behavior when parents �ind an appropriate balance between delivering too little and too much grati�ication.

Personality Structure Based on his patients’ reports, Freud came to believe that personality developed around three essential components: the id, the ego, and the superego. He theorized that infants are governed by basic unconscious instincts of pleasure and their energy is directed to primitive, biological desires. Freud viewed infants as basically sel�ish creatures who are interested only in reducing tension that builds up when their sel�ish needs are not met. Freud called this pleasure- seeking part of the personality the id, which is completely unconscious. According to Freud, although the id dominates an infant’s life, humans spend their lives trying to overcome the aggressive and sexual impulses of the id. Freud might describe politicians who subject themselves to private and public scrutiny by committing moral or ethical violations as “mostly id.” When we engage in pleasure-seeking behaviors without regard to the consequences, it is the unconscious id that is seeking immediate grati�ication.

In Freud’s view, conscious awareness begins to develop in the second and third years. It becomes the job of the ego to satisfy the demands of the id and to have realistic plans for obtaining what the id wants. The ego is rational as it tries to rein in the instincts of the id. It therefore operates on the reality principle as it tries to balance instinctual needs with societal expectations. For instance, instead of forcefully taking a toy that another child is using, a 3-year-old might learn to ask an adult if there are any more toys. This behavior would be the result of the reality principle of the ego.

As the child’s personality matures between the ages of 3 and 6, he or she develops a sense of morality, which Freud called the superego. The superego makes distinctions between right and wrong according to parental and societal standards. When decisions are made, the ego has the dif�icult task of balancing the demands of the id while maintaining rules that the superego dictates. A 6-year-old must balance the demands of wanting a cookie now (id) to satisfy a hunger urge with the admonishment not to eat sweets before dinner (superego). It is up to the ego to �ind a compromise—perhaps asking for a piece of fruit instead.

Evaluation of Psychoanalytic Theory Freud’s theories were quite comprehensive and went well beyond the connection to development that is discussed here. His application of the unconscious to learning, memory, and behavior has pervaded modern study and many forms of psychological treatment. Freudian theory cannot be dismissed from a historical viewpoint, and many of the terms he used, such as anal, ego, and denial, have had a great impact on popular psychology.

However, even though Freud stressed that personality development was established early as a result of the mother- child relationship, he did not study these relationships directly. His view that early psychosexual stages predicted adult personality development (especially psychological �laws) has virtually no empirical support. Indeed, while Freud believed that adult personality was complete well before we reach adulthood (in fact, by about age 6), that is clearly not the case. Instead, his theory incubated during psychoanalysis sessions, which were retrospective accounts and therefore not necessarily accurate accounts of early childhood events. These sessions were also conducted with mostly upper- class European women during the sexually repressive Victorian era. Not only does this population lack broad application, but it may account for Freud’s heavy use of sexuality to explain overall personality. Nevertheless, Freud

used the retrospective accounts from these adult women to form a theory of development that applied mostly to boys (Freud virtually ignored how his theories applied to girls).

Erik Erikson and Psychosocial Theory

Erik Erikson (1902–1994) was a neo-Freudian who thought that psychoanalytic theory put too much emphasis on sexual and aggressive instincts. Erikson argued that Freud misjudged the importance of an individual’s interaction with society and the motivation for humans to be immersed in social customs. Rather than focusing on psychosexual urges as Freud did, Erikson emphasized the process of psychosocial development, introduced in Chapter 1, which includes emotional, personality, and social changes. He believed humans are both formed and challenged by the environment. Psychosocial development is embedded within social tasks that occur over a lifelong process of eight stages. This lifelong social component is in contrast to Freud’s theory, according to which the personality was formed during the �irst �ive years of life.

Erikson’s theoretical goal was not to “complete” stages but to instead address speci�ic crises in order to deal with the con�lict of the next stage. A crisis develops when psychological needs and societal pressures intersect. For instance, a fourth grader has a need to achieve but may have a teacher who puts unreasonable demands on performance. Perhaps the child has a learning disability or is simply asked to complete work that is too dif�icult. According to Erikson, a crisis would develop between the demands of the person and the demands of the social environment. (Erikson’s stages of psychosocial development will be discussed with more detail in Chapter 11.)

Cultures vary in their demands on children, so crises may occur differently depending on the context. For instance, some cultures, such as mainstream culture in the United States, emphasize independence and autonomy and children are usually rewarded for individual effort and competitiveness (Triandis, 1995). Conversely, a child who grows up in Japan is more likely to have a collectivist orientation, in which group cooperation and interpersonal relations are valued over individual accomplishments. Because of these and other differences in cultures, a crisis of development in one culture may not look the same in another.

Nearly all psychologists who study development agree with the lifespan perspective epitomized by Erikson’s work. The importance of social and cultural aspects of development cannot be denied. Most of the attention in research is directed towards Erikson’s views on adolescent identity development and middle adulthood. Though intuitively appealing, the major drawback to Erikson’s theory remains that it is at times ambiguous, and therefore dif�icult to rigorously test (Clark, 2010). Nevertheless, his view of the lifespan has strong contemporary support and thus has a larger focus in Chapter 11.

Learning Theories

Early in the 20th century, psychologists began to question the ef�icacy of studying unconscious processes that are dif�icult to identify and measure. As scientists, psychologists knew that theories should be testable and that it was impossible to measure variables like the id, ego, and superego. Hence learning theory arose. It focuses only on thoughts, feelings, and actions that can be quanti�ied (expressly measured). In this view, learning and development could be studied scienti�ically by observing behaviors that originate from mental events. Early learning theory is often referred to as behaviorism, as its study focused on identi�iable behaviors that were learned through reinforcement or avoided through punishment.

Ivan Pavlov and Classical Conditioning The behaviorist movement was kick-started in 1901 as Ivan Pavlov (1849–1936) was summarizing his research on conditioning re�lexes. Pavlov knew that dogs salivated naturally when presented with food. While studying the salivary response of his laboratory dogs, he observed them salivating to various objects and conditions that were associated with food, but where food was not yet presented. In the same way that a dog or cat might respond to the shaking of a bag of kibble, Pavlov found that dogs would learn to salivate to the sound of a bell, a white lab coat, or a tuning fork (Pavlov, 1927).

This kind of learning through association is called classical conditioning. (See Figure 2.1.) In this type of learning, a neutral stimulus (to which there is no particular response) is paired with a stimulus that elicits an involuntary (natural)

response. For instance, a bell would not ordinarily bring any response, so it is a neutral stimulus; food elicits an involuntary salivary response. When the bell is paired with the food repeatedly and learning is complete, the bell is no longer neutral. The dog has learned to associate the bell with food, even when no food is present. The former neutral stimulus (bell) now elicits the response (salivation) even in the absence of the original stimulus (food). The new stimulus-response relationship is not involuntary, it is learned. Pavlov called the learned response (bell → salivation) a conditioned response. The bell is the conditioned stimulus and the salivation is the conditioned response.

Figure 2.1: Pavlov’s classical conditioning

Before conditioning, the bell had no effect on the dogs’ behavior; the bell was a neutral stimulus (NS) and the salivation was an unconditioned response (UCR). After the bell was paired with food, an unconditioned stimulus (UCS), the bell alone elicited the conditioned response (CR) of salivation.

John Watson and Classical Conditioning A major advancement in learning theory occurred when John Watson (1878–1958) dramatically demonstrated that classical conditioning occurred in humans as well as animals. He famously conditioned a child, 9-month-old Little Albert, to be afraid of rats and other furry objects. First, Watson demonstrated that Little Albert was unafraid of rats and other animals. He then paired a loud noise with a rat by banging on a heavy metal bar behind Albert’s head whenever the rat appeared. Not surprisingly, Albert began to associate the rat with discomfort and fear. He soon became upset whenever a rat was presented, even in the absence of the noise. Note that research of the type undertaken with Little Albert goes

Critical Thinking

Explain how a person might become afraid of snakes by being classically conditioned. Then, describe how people might learn to fear snakes as a result of operant conditioning.

against the code of ethical principles of the American Psychological Association (as well as common sense) and thus would never be pursued today.

B. F. Skinner and Operant Conditioning Though Watson can be thought of as the grandfather of behaviorism, B. F. Skinner (1904–1990) was its greatest proponent. He demonstrated another type of conditioning that went beyond the involuntary responses associated with classical conditioning (Skinner, 1938). According to Skinner, whenever a behavior is reinforced it is likely to be repeated; whenever a behavior is not reinforced (or ignored) it is likely to die out.

People of all ages tend to repeat responses that have been reinforced by applause, smiles, hugs, or money. Any consequence that increases the likelihood of a behavior’s reoccurrence is considered reinforcement. Positive reinforcement occurs when a stimulus is added that increases the frequency of a response. For instance, serving dessert or providing stimulating conversation may increase a child’s polite sitting behavior at dinner. Negative reinforcement occurs when the removal of stimulus (usually something unwanted) increases a response. For instance, taking a disliked food, such as Brussels sprouts, away from a child who has verbally refused it may increase the child’s verbal refusals of food. Positive and negative reinforcement are alike in that they both increase the likelihood that a behavior will be repeated. On the other hand, if an action is not reinforced, it is likely to disappear. If you raise your hand in class and are repeatedly ignored by the instructor, you are likely to stop engaging in “hand-raising behaviors.” In this way, behaviors that are not reinforced die out.

Negative reinforcement is not the same thing as punishment. Whereas both kinds of reinforcement increase the likelihood that a behavior will reoccur, punishment decreases its likelihood. The student who is laughed at whenever he or she gives an incorrect response to a question is punished and is less likely to repeat that behavior. If someone gets sick after eating a particular food, they are less likely to repeat that speci�ic eating behavior. Negative punishment occurs when something that is desired is removed; positive punishment occurs when something undesirable (including a consequence) is added. For instance, parents employ negative punishment by removing a much-desired toy from siblings who are �ighting over it; under the same circumstances, they could also use positive punishment by placing the siblings in separate rooms (adding an unwanted consequence). In both instances, the parents are attempting to reduce the frequency of the �ighting behavior.

Skinner therefore emphasized that development is shaped as a result of learning through patterns of rewards and punishments. He called this type of learning operant conditioning, since people (and other organisms) learn behaviors by operating in the environment. Understanding this type of conditioning is an essential part of understanding how we develop. Skinner �irst demonstrated operant conditioning by training small animals like rats and pigeons. He would reward them as they got closer and closer to a targeted behavior. In one of his classic demonstrations, a rat is rewarded with a food pellet when it �irst approaches a lever; then it must sniff the lever to receive food. Later it must touch the lever to be rewarded. By day 7 or so, it must pull on the lever to receive a pellet of reinforcement. Skinner called this gradual process of modifying behavior shaping. Each step closer to the goal is a successive approximation toward the �inal goal. When shaping behavior, a number of speci�ic goals are usually identi�ied for reinforcement (“baby steps”) before the �inal target is reached. We gradually shape social behaviors by reinforcing speci�ic kinds of etiquette, hygiene, and speech.

On the other hand, extinction of a response occurs when the conditioned behavior (either operant or classically conditioned) is no longer reinforced. If a bell no longer produces meat, a dog will stop salivating. If a joke no longer elicits laughs, you will stop telling it. We do not, however, always understand why behaviors persist, even after a stimulus has been removed. For instance, abused dogs often remain skittish for the rest of their lives, even if they are placed with a compassionate family. And there is evidence that some anxiety disorders, like post-traumatic stress disorder, continue because of a failure to extinguish the fear response, even decades later (VanElzakker, Dahlgren, Davis, Dubois, & Shin, 2014).

Theory in Action: Behaviorism Applied

When compared to psychoanalytic methods pioneered by Freudian theory, behaviorism can be applied in a much more systematic fashion. Therapists do not always need to uncover unconscious con�licts in order to treat unwanted behavior. The treatment of speci�ic behavior issues, like phobias, provides one example.

When I was a practicing psychotherapist, I specialized in the problems of children. One day I received a call from the parents of 10-year-old “Billy,” explaining that he had lost part of his face after being bitten by a dog. Billy had received multiple stitches and was left with massive scars. What took a number of pairings to achieve in Little Albert was achieved in one brief, brutal attack against Billy. He was so traumatized that this previously animal- loving boy even had mixed feelings about keeping his own gentle dog. Intellectually, Billy knew that he loved his dog and wanted to keep her, but he was so terri�ied from his experience of being bitten by a strange dog that he was uncomfortable even looking at his dog from the other side of a glass patio door. In the same way that Little Albert generalized his fear from rats to other furry creatures, Billy had generalized his fear to all dogs. He and his parents asked me to alleviate his fear so that he could once again interact with his own dog.

In these types of cases, therapists often use behavioral principles to eliminate the response. I worked with Billy to replace his fear response with relaxation, since it is physiologically impossible to be simultaneously fearful and relaxed. During 6 months of treatment, I used a combination of distraction, hypnosis, and relaxation techniques while exposing Billy to progressively more fearful situations. Each exposure level was planned systematically to eliminate Billy’s fear response. At �irst, Billy was afraid to look at photos of gentle dogs. After he was able to tolerate those photos, I gradually exposed him to photos of dogs that appeared angry. When I �irst met Billy, he would not look out the window of the car for fear he would see a dog. A couple of months later, Billy was able to comfortably watch his dog from the other side of the glass door and could drive past the dog park without cowering.

We then worked on exposure to live dogs. I eventually brought in my own family dogs because I knew they would remain calm in a corner of the of�ice if necessary. Billy actually began to interact with my dogs before allowing his own dog into the house, probably because he associated my of�ice with a deeper level of relaxation than his home. However, not long after that, he was able to take his dog for a walk and then move her back into the house. After another month or so, he was functioning nearly as he did before the attack.

Albert Bandura and Social-Cognitive Theory Although Skinner clearly demonstrated how responses change, pure behaviorism does not explain all learning. Albert Bandura (1925– ) showed that behaviors emerge even without reinforcement or punishment; we can also learn by observing others. Bandura famously demonstrated that the social environment and cognition play interactive roles in behavior. This model for learning is now called social-cognitive theory. In his classic study using children who watched adult models punch a “Bobo” doll, Bandura demonstrated that reinforcement was not always a factor in eliciting behavior. We also learn by modeling (or imitating) the behavior of others. Imitation partly explains how babies learn to smile, children learn to do “cannonballs” in a pool, or adults learn to behave in a new environment without being reinforced.

The four steps in social-cognitive learning demonstrate the interaction of operant principles and cognition (Bandura, 1986):

1. Attention: The individual must �irst pay attention to something in the environment. The event’s most critical features receive the most attention.

2. Retention: The individual must successfully translate the event into a concept that can be remembered. 3. Reproduction: The individual needs to be able to convert the remembered concept into appropriate behavior. 4. Motivation: The individual must be suf�iciently motivated through reinforcement or punishment to engage in the

behavior. The environment initiates the consequence that ultimately causes the behavior to be repeated or not.

Critical Thinking

Name some behaviors that you believe you have learned in the absence of reinforcement and punishment.

Ingram Publishing/Thinkstock

Piaget studied the differences in mental limitations between children of different ages, eventually mapping out distinct stages of brain development.

Bandura’s approach to learning has many practical applications. Like other psychological learning models, though, it falls short in trying to explain all behavioral outcomes. For example, although observational learning can explain why the vast majority of abusive parents report that they were abused as children (Garbarino, 1984), the reverse is not true: Many children make a conscious decision to behave differently from their parents. In fact, over 70% of children who are abused do not grow up to abuse their own children (Cicchetti & Toth, 2006). Researchers and theorists explain the different outcomes by the strength of the cognitive side of learning. In the social-cognitive perspective, the environment is regarded as a mechanism for feedback. Someone who is abused can use observational feedback and thought to make decisions, without necessarily modeling negative behavior.

Cognitive Theories

No one has been more in�luential in the �ield of cognitive development than Swiss biologist and psychologist Jean Piaget (1896–1980). While administering Binet’s intelligence test to Parisian schoolchildren, Piaget became fascinated by children’s incorrect answers. After many years of observing the mental limitations of children, including his own children, Piaget came to the conclusion that children of different ages think differently. Mental activity evolves in a predictable pattern of distinct stages related to natural maturation of the brain (Piaget, 1983).

Lev Vygotsky (1896–1934) was another in�luential theorist whose ideas included a strong cognitive component. To Vygotsky, the context in which learning takes place is key to development; hence, his theory is often referred to as a contextual (or sociocultural) model. Culture determines what is most important to know. For instance, a child who grows up in an agrarian society in Bangladesh needs a different kind of knowledge than the advanced linguistic and reasoning skills taught in a prep school in New York City or Tokyo. In addition, regardless of the community, learning is social. Children learn by interacting with others and by receiving assistance when they are learning tasks that are just outside their current levels of achievement.

Many contemporary cognitive psychologists have also been in�luenced by the computer age and more detailed knowledge of the brain. Supporters of the information-processing theory of cognition compare thinking to computer systems in the way that both humans and electronic devices take in, store, and use information. This theory focuses on how information �lows through the system, especially with regard to memory. Thinking can be mapped like a �lowchart to understand how we solve problems. We become better processors of information (more advanced cognitively) as we gather more knowledge, encode it in memory, compare it with other memories, and �inally make an appropriate response. These perspectives on cognitive development are examined more closely in Chapter 7.

Systems Theories

Systems perspectives acknowledge the complex association between the environment and development. The bioecological approach views development as a series of interconnected systems that cannot be studied independently. Dynamic systems theory attempts to explain development as an accumulation of all factors large and small that may be acted on in any given moment of development.

Urie Bronfenbrenner and Bioecological Systems Theory At �irst, psychologist Urie Bronfenbrenner (1917–2005) proposed that human development is best understood by studying the ecological systems under which development takes place. According to this ecological perspective, contextual variables operate within a complex structure of individual and community relationships (Bronfenbrenner,

1979). It is theorized that development is determined by the relationships among various environmental systems. Some are indirect, including those related to governmental institutions and policies, schools, health services, and social networks like churches and recreational sports leagues. On the other hand, there is a direct in�luence of family, peers, and neighbors. These systems operate simultaneously and illustrate how context is key to a person’s development. Bronfenbrenner later revised his theory to acknowledge the essential nature of biology and genetics, as well. Hence, Bronfenbrenner’s contemporary perspective is now referred to as bioecological systems theory (Bronfenbrenner, 2005).

Figure 2.2 shows the bioecological systems model and how context ranges from a child’s immediate surroundings to a society’s laws and values. The microsystem has a daily, direct impact on an individual’s immediate environment. Teachers, parents, and school bus drivers have constant in�luence on development. The mesosystem represents the interaction of the various components of the microsystem, like parental involvement in school and a child’s friends. A stressful morning at home may impact the day at work or school, demonstrating the connections between microsystems.

The exosystem includes community and socioeconomic variables that have a less direct impact. For example, there are circumstances when parents have to (or choose to) work more hours, or when there is a change in government social policies. Though indirect, the in�luence of the exosystem can nevertheless be profound.

The macrosystem represents the cultural context, such as laws, traditions, and customs. For instance, some governmental and cultural institutions have programs that broadly support health, education, and welfare of all. In other nations, simply being a girl will restrict access to schooling.

Finally, the chronosystem shows the social and historical context within which the other systems operate, and how the four systems change over time. Elections, wars, and natural disasters may change developmental outcomes for an entire cohort. These interactive systems demonstrate how development is a complex, ecological process.

Figure 2.2: Bronfenbrenner’s bioecological systems model

Bronfenbrenner’s theory emphasizes individual and contextual variables that impact development.

Source: Adapted from Urie Bronfenbrenner, The Ecology of Human Development. Cambridge, MA: Harvard University Press, 1979.

Esther Thelen and Dynamic Systems Theory Gaining inspiration from behaviors rooted in biology, Esther Thelen (1941–2004) and her colleagues embraced a more contemporary dynamic systems theory, which attempts to more fully explain variations in human behavior. Instead of a maturational plan, dynamic systems theory views development as individually self-organizing (Smith & Thelen, 2003; Thelen, 1992). That is, instead of focusing on linear development, dynamic systems theorists explore how the interaction of the mind, body, and social environment customize an integrated, dynamic (constantly moving) system. Each behavior is “assembled” from the interaction of multiple systems (Spencer et al., 2006). Systems range from molecular to societal and might occur within milliseconds or accumulate over decades.

This perspective attempts to understand the “microdevelopmental” dynamics of the transition—”how” the moment of change occurred—rather than focusing on “when” (Thelen & Corbetta, 2002, p. 55). For instance, we know that, on average, infants will begin to pull themselves to a standing position at around 9 months of age. According to dynamic systems theory, the process of pulling oneself to a standing position is not simply programmed. In addition to brain maturation, coordination is necessary between muscle movement, perception, motivation, and mental processes. For each infant, the mix of variables will prescribe the moment of transition. Individual exploration, which offers new challenges and encounters, is what leads to new levels of organization. How that new organization occurs is based upon “every neural event, every reach, every smile and every social encounter, [which then] sets the stage for the next” (Smith & Thelen, 2003, p. 348).

The dynamic systems theory incorporates biology and genetics, evolution, learning, cognition, contextual perspectives, and more. This perspective illustrates the modern approach in general, which has shifted the study of development from simple stimulus-response relationships indicative of behaviorism to more complex systems. Next, we will look at how these different perspectives guide and organize research, leading to new understandings and intervention strategies.

Section Review

Trace the historical evolution of psychological theories. How do different theorists emphasize different parts of human behavior?

Figure 2.3: Education and median weekly earnings

Researchers use theories to help predict outcomes, modifying or expanding their theories once data is gathered. Researchers studying the relationship between educational attainment and weekly earnings might use the information presented in this �igure to help rede�ine their theories.

2.2 The Scienti�ic Study of Human Development

To properly understand and integrate what they theorize about development, psychologists conduct empirical research to systematically gain information and reach conclusions. However, research in social science rarely proves anything. (In their writing assignments, inexperienced psychology students often make the mistake of stating that results of a particular study prove something.) More commonly, “evidence suggests” or “data show” a particular result. Consider the following examples:

Evidence suggests that maternal stress has an effect on fetal and child development (Graignic-Philippe, Dayan, Chokron, Jacquet, & Tordjman, 2014). Data show that 39 percent of the world’s adults are overweight, but because of potential counting errors we are not entirely certain we know the true number (WHO, 2015b). Data suggest that people who exercise and achieve a higher level of �itness in their 40s are more likely to have greater brain volume and (therefore greater cognitive health) in their 60s (Spartano et al., 2015).

Psychology is rarely exact. Patterns of outcomes are not the same every time we measure a group or for every person in every circumstance. Sometimes a part of a population is so unlike the rest of the population that we can presume it re�lects a different population. For instance, contrary to what most people would think, it is found that college students who persist from semester to semester (continue their education), on average enroll in more units than students who drop out. Therefore, we can conclude that students who take the most classes are different than other students (Nakajima, Dembo, & Mossler, 2012). It is also possible that the result of one study occurred randomly; strictly by chance, perhaps we selected a group of persistent students who had enrolled in a lot of units, and, unbeknownst to us, other high-enrollment students did not persist. When the probability that an outcome occurred simply by chance is 5% or less, we say there is statistical signi�icance. That is, the probability that we found a difference between two groups, when none really existed, was less than 5%, resulting in a statistically signi�icant result. As signi�icant results on the same topic begin to mount, we can begin to say a theory has support—in this case, students who enroll in the most units are different than other students.

Regardless of whether results are statistically signi�icant or not, in the scienti�ic approach something of value is always learned. For instance, in an experiment to determine the effect of a particular antidepressant on the treatment of depression, any conclusion provides valuable information. If results indicate either that antidepressants improve mood or that they do not, the research expands the range of knowledge about antidepressant medications.

Hypotheses in Research

Researchers construct theories and try to predict outcomes. A theory may be based on other theories, prior research, or simply guessing. For example, we might make a prediction that those who earn college degrees will make more money over their lifetimes than those who do not. Although this relationship is not always true, on average it is (see Figure 2.3 for a graph of this �inding). Therefore, there is a foundation for predicting adult outcomes: Someone with a college degree is likely to have a higher salary than someone without a degree. After con�irming these results, we may want to re�ine the theory to focus on more speci�ic predictions—maybe including the ways in which gender, culture, and geographic area change outcomes. It is not uncommon to modify and expand theories as more information is gathered. Predictions are then modi�ied and the cycle continues.

A hypothesis, or scienti�ic prediction, is the beginning of the research process. Some examples include “Older adults who have consistently engaged in vigorous exercise are less likely to suffer from chronic

Source: Adapted from Bureau of Labor Statistics (2015). Employment projections.

pain than older adults who have not consistently engaged in vigorous exercise” or “If depressed individuals take antidepressant medication as prescribed, then they are less likely to suffer depressive symptoms than depressed individuals who do not take antidepressant medication.” After forming a hypothesis, a research design is chosen based on the question being investigated.

Good research is nearly always published in the kinds of peer- reviewed, professional sources found in the reference section of this text. Well-designed studies that take pains to be free from bias would never be reported exclusively on a personal website. Research that passes peer review is orderly and follows accepted step-by-step scienti�ic procedures. Other researchers must be able to replicate (repeat) the study to verify results. If other researchers are not able to replicate the results, sometimes the original study is questioned.

In a recent study, for example, it was reported that a single 20-minute conversation with a gay pollster produced a long-term shift in support for same-sex marriage (LaCour & Green, 2014). The scienti�ic community was surprised at this �inding, since it is well known that this type of interaction usually does not change people’s minds. Other researchers were able to comb through the original research and found substantial inconsistencies. The original author (through his attorney) later admitted to fabricating data, and the prestigious journal Science published an embarrassing, rare retraction soon thereafter (Broockman, Kalla, Aronow, 2015; McNutt, 2015). Although in this case the study still appeared in press, because the original research was subject to professional review standards, the peer-review process eventually did its job.

Understanding Research Design

Part of becoming a good student of research is also becoming a good consumer of research. That is, you need to develop the skills to differentiate the good research from bad, noteworthy �indings from trivial information, and serious research from propaganda. Do early relationships with parents predict adult romantic relationships? Will doing crossword puzzles prevent dementia? Does a parent’s sexual orientation have an effect on children? Research can help us �ind the answers to these questions.

Let’s hypothesize that speci�ic kinds of medications will alleviate the symptoms of depression. First, we must identify a population for research. If we decide that we will study depressed adults between the ages of 20 and 60, then a group of adults who are similar to the population of all depressed adults need to be selected. That is, every depressed person in the world (the population of depressed adults) cannot be tested, so the sample of study participants must be representative of the population, as shown in Figure 2.4. This group is known as a representative sample. If the sample has characteristics that are similar to the population as a whole, we can use the study to make general statements about the effect of medication on all depressed adults.

Figure 2.4: Representative sample of a population

A sample is a subset of a population. It is important that samples are representative of the population in general, but it is nearly impossible to know for certain if they are.

Ethical Considerations

Consider again Watson’s experiment that featured Little Albert and the rat. If you were disturbed by how Little Albert was treated during the experiment, you were thinking clearly. Today there would be blatant ethical concerns if we were to purposely instill fear into a child. In order to prevent these types of circumstances, the American Psychological Association (APA) and the Society for Research in Child Development (SRCD) have established speci�ic ethical guidelines to protect children and others from harmful research practices (Sales & Folkman, 2000; Smith, 2003). In addition, most universities and government research agencies have an ethics board (usually referred to as an Institutional Review Board, or IRB) that examines every application for research. Basic considerations that are reviewed include the mandate to do no harm, ensuring there is informed consent, justifying any use of deception (and the necessity to debrief participants), and maintaining privacy.

Section Review

Explain the importance of using appropriate design in developmental research and how conclusions might be applied.

2.3 Descriptive and Correlational Studies

To begin our study, we must choose from among a number of methods, each of which has advantages and disadvantages, depending on the research question. Sometimes, because of convenience or design, behavior is simply recorded. What are the most popular college majors? Do hospital nurses treat male and female patients the same? What are the most common crimes that adolescents commit? These types of questions do not require cause and effect predictions as in an experiment. These questions only require researchers to gather information. After data are collected, they can be described. Hence, we use the term descriptive research, which will be explored in more detail in this section.

Case Study

Sometimes researchers want to study unusual behaviors or to intensely study the behaviors of single individuals. For instance, psychiatrists have recently been experimenting with hallucinogenic drugs to treat symptoms of post-traumatic stress disorder and other kinds of severe anxiety (Gasser et al., 2014; Mithoefer, Wagner, Mithoefer, Jerome, & Doblin, 2011). The preliminary success of just one person who was prescribed Lysergic Acid Diethylamide (LSD) in a controlled case study can lead to the pursuit of more widespread experimental trials. Although the ability to generalize the results of one case (its generalizability) to the larger population is usually limited, this method can be a valuable catalyst to pursue new areas of research.

Case studies incorporate a wide range of methods, including testing, observation, and interview. It is also perhaps the most common method that consumers use to make incorrect conclusions. If one person reports that a “miracle diet” ends food cravings it may result in television appearances and book sales, but it is probably not true. If one child reacts badly to yellow food coloring, it does not mean that every child will be harmed by it. Conclusions that are based on independent stories are often referred to as anecdotal evidence. If a shoe �its one person, it would be foolish to think it would �it every other person or to conclude that one case can be generalized to an entire population. For this reason, case studies are often a poor substitute for good research. Instead, we must design studies that have more generalizable outcomes as much as possible.

Naturalistic Observation

Whether studying the case of one individual or the behaviors of a group, researchers often go into environments that are free of standardized procedures that might exist in a controlled laboratory. Naturalistic observation affords researchers the opportunity to record “realistic” data without intervention or disruption. We can go to any number of everyday settings to observe people in their natural surroundings, such as a preschool, a senior center, a subway terminal, a college campus, a nightclub, or a business meeting.

While ordinary observation has the advantage of being in a real-life setting, it also has its drawbacks. Not all environments are conducive to one-way mirrors, cameras, or a conspicuous observer. And if participants know they are being watched, they may alter behaviors. We call this circumstance an observer effect. Family members, college students, or couples may act differently if they are aware of being watched.

Surveys and Questionnaires

Perhaps the most ef�icient way to get information is to simply ask for it. Surveys, sometimes referred to as self-reports, are especially useful when researchers want to get a lot of information and only have limited resources. Whereas case studies take an enormous amount of time to study a small number of people, the reverse is true with questionnaires. Survey data are sometimes the easiest to collect because they can reach a large number of people quickly and ef�iciently.

In order to study the effects of antidepressant medication on mood, for example, survey questions could be sent to everyone who takes medication. Participants would �ill out questionnaires on how much medication they take, whether their weight has changed, how much they sleep, what their mood and activity level is like, and so forth. The surveys would need to include the same questions for every

iStock/Thinkstock

Though they can be subject to response bias, surveys and questionnaires can be the most ef�icient way to collect data from a large number of people.

respondent so that answers are closed to interpretation as much as possible—remember that in descriptive research the goal is to collect only facts.

However, like case studies, surveys are subject to response bias, or an individual’s tendency to respond in a certain way regardless of the question being asked. Sometimes respondents may give what they think are socially acceptable answers, even though they may not be doing this consciously. Respondents may exaggerate their responses or not answer carefully or honestly. The problem in research is that we never know if or when participants are answering accurately. In addition, voluntary surveys almost always have a return rate that is signi�icantly less than 100%. The high response rate on support for gay marriage reported in LaCour and Green (2014), which we discussed in the section about scienti�ic study, was one of the irregularities that initially alerted critics. Is it possible that people who participate in surveys are different from those who do not? The de�initive answer is “maybe.” Truth is sometimes hard to get at, and research in general is confounded by the knowledge that we can

never know whether people who participate are any different from those who do not. It is therefore often impossible to know how accurate survey results are. That is why we say that results are suggestive rather than factual.

Correlational Research Design

Correlational research design describes the strength of a relationship between two variables that already exist. In this design, we test variables that may be related to each other without assuming there is a cause-and-effect relationship; they are strictly predictive. Consider the following examples:

A relationship between aging in adulthood and perceptual speed (Schaie & Willis, 2010) can help us predict that increasing age will lead to lowered perceptual speed among a group of middle-aged or older adults. A relationship between SES and smoking cessation (Stewart et al., 2013) can help us predict that lower SES will predict fewer adults will quit smoking (or, alternatively, higher SES will predict more success) among a group of middle-aged and older adults. A relationship between number of hours of media use (e.g., texting, television, video games, computer) and grades of �irst-year college students (Walsh, Fielder, Carey, & Carey, 2013) can help us predict that more hours spent on media among �irst-year college students will lead to lower grades in college.

We express the strength of correlational relationships numerically with a correlation coef�icient. This number ranges from –1.0 to +1.0. If two variables move in the same direction, we say there is a positive correlation. For example, as SES rises, the number of people who have quit smoking rises as well. Similarly, as SES falls, fewer people quit smoking. A negative correlation exists when variables move in opposite directions. The strength of the relationship is still re�lected in the correlation coef�icient, so a coef�icient of –0.70 is stronger than +0.40, but it is an inverse relationship. As age increases, coordination and perceptual speed decreases. As hours spent on media increase, grades decrease. These relationships represent negative correlations.

Finally, no meaningful relationship exists when there is a low correlation coef�icient. For instance, there is no relationship between periodontal disease and depression, or depression and bone density, or handedness and sexual orientation (Iacopino, 2009; Rosentein & Bigler, 1987). Therefore, the correlation between each of these pairs of variables is at or near 0.0. Figure 2.5 summarizes the direction and strength of three general types of correlations.

Figure 2.5: Correlation

Graphic representations of (a) a positive correlation, (b) a negative correlation, and (c) two variables that have no relationship.

The majority of developmental research utilizes correlations in some way or another. This is because we often want to describe outcomes based on age, and age cannot be manipulated as in an experimental design (as you will see later in this chapter). We can compile correlational data through surveys, naturalistic observation, and other methods, as long as we keep in mind that correlation does not translate to causality. For instance, in one well-regarded study, hormone replacement therapy (HRT) during and after perimenopause was found to be associated with lower incidence of cardiovascular disease. However, questions arose when later analyses discovered that on average women on HRT were wealthier than women who were not, and wealthier women are more likely to engage in the types of exercise and nutritional regimens that are associated with less disease (Stampfer & Colditz, 1991; Lawlor, Smith, & Ebrahim, 2004). Therefore, income level predicted both the likelihood of HRT and cardiovascular disease. Hormones did not necessarily cause a reduction in heart disease; instead, a third factor (income level) predicted both access to hormone therapy and cardiovascular health. Indeed, later studies have found the relationship between HRT in women and cardiovascular events in general to be quite complicated (Shufelt et al., 2014). This subject underscores why we need to be cautious and not assume that correlation signi�ies a causal link.

Section Review

Why are certain kinds of scienti�ic study referred to as descriptive research?

2.4 Studying Change Over Time

Developmental research has a heavy interest in studying change over time. There are several issues to consider when investigating these kinds of changes, depending on the availability of participants and the variables being studied. The three designs discussed in this section yield individual challenges, but they are particularly useful in studying development.

Longitudinal Study

In a longitudinal study, researchers record information about the same persons at different points in their lives—over a “long” period, as the name implies. Intervals can be as long as decades or as short as is necessary to test for developmental changes. For instance, understanding the trajectory of cognitive development is best studied over many decades. On the other hand, following the onset of a fatal disease, we might test for mental or physical �itness on a weekly basis. Longitudinal study intervals are almost always prearranged and regular. In this way we can learn about individual variability by testing the same people at Time 1, Time 2, Time 3, and so on. We know, for instance, that on average 30-year-olds have better memories than 75-year-olds, but not everyone changes at the same rate or for the same reasons. If we were to measure people of different ages at the same time, it would only yield averages across the lifespan. If researchers want to learn more about individual change and variability, a longitudinal design will address those differences.

One group of researchers used this method when they looked at the ways in which early developmental variables recorded at age 5 might contribute to romantic relationships between ages 18 and 25 (Rauer, Pettit, Lansford, Bates, & Dodge, 2013). To survey young adults about their experiences during early childhood, where they would have attempted to recall information from years ago, would not yield the same accuracy or richness of data compared to collecting information year by year. Longitudinal analysis allows the researchers to have an orientation to individual differences while simultaneously attending to group patterns that might arise. There is one longitudinal study that you will read about in Chapter 9 that has gone on for more than 75 years (Vaillant, 2008).

There are several drawbacks of the longitudinal approach. If we want to study development of the same group of individuals, the research may take years—even decades—to complete. There are also the logistics and costs of tracking the original participants. There is nearly always a certain amount of attrition. We never know whether those who have dropped out of a study (or died) would have provided different results than those who remained. Consider again LaCour and Green (2014), which we discussed in the section about scienti�ic study. The reported demographics of voters who responded to follow-up requests were identical to those who did not respond. As critics note, ordinarily those who are successfully reached during a follow-up phase “differ in systematic ways” (Broockman et al., 2015, p. 3).

Cross-Sectional Study

Consider again the longitudinal study that looked at the ways in which developmental variables at age 5 might contribute to later romantic relationships. In this example, we cannot follow the types of child or adolescent relationships that lead to different marriage outcomes. Individual effects of drug use, exercise, extended education, nutrition, parenthood, and so on affect individual outcomes that will not show up within group averages. But what if we enlisted people of several different ages? A cross-sectional study avoids the problem of tracking down original participants and reassessing them. In this type of research, we concurrently test individuals across different ages (a cross-section of the population). In this design, issues related to continuity are dif�icult to investigate, but it is quite useful for understanding averages.

Further, in a cross-sectional design (see Figure 2.6), each age range represents its own group, or cohort, that has characteristics not shared by other groups. It is a major variable in adult development research and the principal factor that confounds cross-sectional studies. For instance, researchers cannot immediately conclude that musicality increases throughout the lifespan if it is found that a cohort of 65-year-olds is more musically talented than a college-age cohort. Over time, the emphasis on music education in families has changed, and schools have at various times encouraged or discouraged overall education in the arts. As we learned in Chapter 1, people who are born in the same city or who live through similar historical experiences can de�ine a cohort. When these generational or group differences skew cross-- sectional studies, it is called a cohort effect.

Figure 2.6: Cross-sectional research designs

Middle cells represent the ages of the individuals at time of testing. Any horizontal row indicates a longitudinal design, like the 1955 cohort in blue. Any vertical column represents a cross-section, which is a research design that is used to compare people who are from different cohorts, as indicated by the gray oval. If that vertical group of cohorts is studied over time (the gray oval would move to the right as each cohort ages), it would become a cross-sequential study. A cohort sequential study compiles data from two or more longitudinal groups (cohorts), as indicated by the two groups in orange ovals.

Sequential Study

A sequential study combines the longitudinal and cross-sectional designs, as depicted in Figure 2.6. That is, researchers study a number of cohorts over time in a “sequence” of studies. In this way, we attempt to estimate the magnitude and nature of age effects. The sequential design is on display as newer groups are recruited and followed in the Seattle Longitudinal Study (SLS), which has tracked changes in cognitive development since 1956 (Schaie & Willis, 2010). Large data collections on the original cohort have occurred every 7 years, but Schaie and his colleagues have also recruited new cohorts. The sequential study is able to isolate cohort effects of, for instance, differences in availability and usage of technology, �itness levels, and access to education and healthcare. Indeed, cohort differences have led to the discovery of behaviors that optimize cognitive functioning as we age (Schaie, 1990). While a sequential study is usually more complicated and expensive than either a longitudinal or cross-sectional study, it also provides the most robust results, as it conquers major limitations of other designs. Nevertheless, it still does not de�initively separate age effects from environmental and cohort effects.

There are several kinds of sequential studies, which yield separate, relative effects for cohort, time, and age. A cohort- sequential study compiles data from two or more longitudinal groups (cohorts). For instance, we might want to compare how weight and amount of physical activity has changed over time for those born in 1990 versus those born in 2000. We could collect data each year beginning at age 5, for both groups, so that weight and activity levels at corresponding ages could be compared. Collecting data for only one year may not be suf�icient because we would want to see cohort trends, not just a snapshot in time. In other instances, we indeed might want to compare groups of the same age, but of different generations. For instance, we could measure marriage and childrearing attitudes among 20-year-olds, 30-year- olds, and 40-year-olds who are born generations apart. That is, we could measure the three age groups in 1975, 1995, and 2015 (nine groups altogether) and determine how attitudes at different ages might have changed over time. This approach is called time-sequential design as depicted in Figure 2.7. It is also sometimes important to understand how changes occur over time among cohorts of different ages, like children who are learning a foreign language. Here, we might introduce a three-year foreign language program to 6 cohorts, one for each grade from kindergarten to �ifth grade. A cross-sequential design would inform research about the most ef�icient age at which to begin foreign language instruction (see Figure 2.6).

Figure 2.7: Time-sequential design

In a time-sequential design, cohorts are measured at Time 1, and the efforts are duplicated later with new cohorts whose ages match the earlier cohort.

Section Review

Compare and contrast the research designs that can be used to study change over time.

2.5 The Experimental Method

Though descriptive studies like the SLS are indicative of the most common types of developmental research, the feature that perhaps best de�ines psychology in general as a science is the use the experimental method. In this process we manipulate one variable to investigate the changes that occur in another variable, using speci�ically identi�ied, replicable procedures to establish a cause-and-effect relationship (see Figure 2.8).

Figure 2.8: The experimental method

The experimental method allows psychologists to study possible cause-and-effect relationships.

Independent and Dependent Variables

In the experimental method (see Figure 2.8), researchers specify variables that will be manipulated and measured; they identify other variables that are speci�ically ignored, or controlled. The independent variable (IV) is the variable we manipulate. For instance, when testing the effect of medication on depression, the type or amount of medication is the IV because the experimenter is in control of its variability. We might prescribe different dosages or brands of medications, and then measure the level of depression. Alternatively, we could measure the effect of medication versus increased physical activity, yoga, or different kinds of talk therapy. There may be one or many IVs, but they are independent because they are manipulated in the research independently of other factors.

On the other hand, the dependent variable (DV) is the factor that can change. As we manipulate the IV, we record its effect on the DV. So as we manipulate antidepressant medication, we measure the level of depression—the DV. We do not control how individuals will respond. Instead, we want to know how mood is dependent on different kinds of treatment. The big question in social science research is, “Do changes in one or more independent variables cause changes

in the dependent variable?” If medication delivery leads to differences in levels of depression, then researchers can claim a cause-and-effect relationship.

Operational De�inition

Knowing the speci�ic structure and terminology of any study—not just experimental designs—is essential to understanding results. One of the most often overlooked issues in research is the operational de�inition. It explicitly identi�ies what is being measured and the process for doing so. We can maintain some consistency in the identi�ication of different antidepressant medications, such as the brands Paxil® or Zoloft®, but what about depression? How would we de�ine that? Researchers must speci�ically identify variables so that those who conduct, analyze, and attempt to replicate research have a shared understanding of their meaning. We can usually de�ine variables like age and time without much dif�iculty. However, factors like “mood” and “activity level” are much more complicated to describe. Before beginning any investigation, it is �irst necessary to de�ine all variables as explicitly as possible.

Activity

Construct an operational de�inition for (1) aggression, (2) addiction, or (3) depression. You must have speci�ic parameters that are standardized and therefore comparable.

Extraneous Variables

Especially in developmental research, it is sometimes dif�icult to control all the variables that may affect outcomes. Some people weigh more than others; some might take vitamin supplements; others may have obligations that infringe on sleep. As discussed earlier, how data are collected, including the attitude and mood of the researcher, may have an effect on the very behavior that is being recorded. It seems logical to assume that these factors will cause changes in the dependent variable; however, often we cannot know whether they will or not. All of the factors that may affect results but are not accounted for are called extraneous variables. They can potentially contaminate the research, but often we simply do not know whether they do or not. We try to neutralize the extraneous effects by treating groups the same (see the next section), but it is not always possible. If researchers write up their studies appropriately, they will identify the extraneous elements that are potentially in�luential. However, in the interest of making results look better or to appeal to a broader audience, identi�ication of extraneous variables is often left up to the consumer of the research.

Experimental and Control Groups

There are many different ways to test the theory that antidepressants reduce depression. Most commonly, we want to understand causality by a number of factors, not just the presence or absence of medication. We also want to know about the effects of age, social opportunities, and physical activity, for example. In this example, we would need to perform more sophisticated multivariate analyses because there are several independent variables and dependent variables that should be considered simultaneously. (Multivariate designs are also used in correlational research when there is more than one variable that is being used to predict outcomes.)

In the simplest experimental design, which we will use as an example, we only have one IV—antidepressant medication (or no medication). Although every participant in the study has symptoms of depression, only half will receive antidepressant medication. They are assigned to the experimental group (or treatment group). In order to know whether drugs make a difference, the individuals who remain will not be exposed to the treatment. This second group is called the control group. Each person has an equal chance of being assigned to either the treatment group or the control group. This process is called

iStock/Thinkstock

The control group of an experiment will be randomly assigned to receive placebo pills, which look identical to the experimental pill but have no active ingredients.

random assignment, and is akin to drawing names out of a hat. Random assignment allows us to assume that the two groups are identical. This procedure allows us to manage extraneous variables, but because of chance occurrences, the two groups may nevertheless not be identical.

For our study of depression, let’s assume every person in the experimental group is prescribed 50mg of sertraline (Zoloft-). In most drug studies such as this hypothetical one, the control group is given a pill that contains no active ingredients but looks the same as the experimental pill. It is important to have a benign placebo so that researchers can be certain that results are due to the drug being tested. That is, in some instances the placebo may produce the same effects as the drug because participants think it should, and their bodies or minds respond. This phenomenon is called the placebo effect. It can be quite powerful and has helped to alleviate symptoms over a wide range of conditions, including pain management, mental disorders, and Parkinson’s disease (Barber, Barrett, Gallop, Rynn, & Rickels, 2012; de la Fuente-Fernandez et al., 2001; Dobrila-Dintinjana & Nacinović-Duletić, 2011).

Section Review

Suppose you wanted to study the effects of caffeine on short-term memory of college students. How would you design the experiment? Name the independent and dependent variables, including their operational de�initions, the experimental and control groups, and at least one possible extraneous variable.

NEXTNEXT

2.6 Becoming a Good Skeptic

Interpreting results of research presents other challenges as well. For instance, drug makers fund a great deal of the research in psychopharmacology (the study of the use of drugs to treat mental disorders). That makes sense, of course; who else would want to know about patient responses to medications? One major problem though, is that if results do not �it the needs of the funding source, they sometimes go unpublished. This situation represents another kind of bias, since only bene�icial results might be published.

Such has been the case in studies on the effect of anti-depressant medications. Irving Kirsch and his colleagues combed through both published and unpublished studies and analyzed them in a major meta-analysis, which is a research and statistical review that combines results from multiple studies. The meta-analysis revealed that anti-depressant medication was not signi�icantly better overall at alleviating symptoms of depression than placebos. That does not mean that medication is not successful, it is. However, in these studies medication was not shown to be signi�icantly more successful than placebos. Interestingly, drugs and placebos both have a stronger effect when initial symptoms of depression are more severe (Kirsch et al., 2008; Kirsch, Moore, Scoboria, Nicholls, 2002; Moncrieff & Kirsch, 2005).

More recently, other meta-analyses have found that medication is slightly superior to placebo, but only in severe or acute cases (Fournier et al., 2010; Linde et al., 2015). As such, some people in the �ield have questioned how marketing might be confounding results of scienti�ic studies (Antonunccio, Burns, & Danton, 2002). Even psychiatrists and general family practitioners are still unaware that anti-depressants do not have the ef�icacy they are purported to have (Lawrence et al., 2012).

Therefore, it is imperative to look at research with a critical mindset. It is an essential—and required—responsibility of academic study to become a good skeptic. Anecdotal evidence is not a substitute for good research; only controlled experimental studies can properly answer the question of cause and effect. Anti-vaccination alarmists, miracle weight loss products, and conditions like depression that appear to have standard treatment protocols alert us that we need to critically question conclusions. Just because a view is widely accepted or someone says something is true does not make it so. It is your job as a student of social sciences to understand the limitations of research and challenge conclusions. Understanding research techniques and methodology will help you in this ongoing endeavor. If something you read in this text does not make sense, scrutinize the details, do your own research, think critically, and challenge the conclusions!

Section Review

Outline the experimental method. What are some potential problems in research?

Summary & Resources

Chapter Summary Theory provides the foundation needed to move forward in the study of lifespan development, providing for scienti�ic investigation. We began this chapter with an introduction to popular theories—a discussion of how they have evolved and how they organize thought. The major theories allow us to investigate development from a number of different perspectives. Researchers must then carefully choose the method of investigation that is most appropriate and adhere to professional standards while conducting their studies. Understanding how research is conducted and its potential �laws is essential to the scienti�ic study of the lifespan. Throughout the text, you will incorporate your understanding of theory and research to identify the physical, cognitive, and psychosocial processes that affect stability and change throughout the lifespan.

Summary of Key Concepts Theoretical Foundations: Major Perspectives of Human Development

Theories are necessary to direct and organize the study of lifespan development. In order to ask questions about developmental experiences, there must be a theoretical framework. Using theory as a foundation allows us to describe, predict, and explain events and behaviors. Ideally, the goal of theory and scienti�ic study is to develop an application that will improve people’s functioning.

Sigmund Freud and Psychoanalytic Theory

Sigmund Freud’s psychoanalytic theory was in�luential in elevating the �ield of psychology, but he did not directly study childhood development. Freud’s theory of psychosexual stages focused on the pleasure that he believed was inherent to different body parts. Psychoanalytic theory says that we are governed by unconscious instincts of pleasure and we direct our energy to primitive, biological desires. These lead to the development of the basic structure of the personality, the id, the ego, and the superego.

Erik Erikson and Psychosocial Theory

Erik Erikson’s model of psychosocial development stresses the importance of relationships with other people throughout the life course. Each stage of psychosocial development has a corresponding crisis between the demands of the person and the demands of the social environment.

Learning Theories

Early psychodynamic theories spawned a wave of behaviorists that focused on speci�ic measurable outcomes. Physiologist Ivan Pavlov inadvertently discovered the process of learning through association. His experiments on classical conditioning ushered in the era of behaviorism. John Watson’s experiments with Little Albert demonstrated that classical conditioning occurred in humans as well as animals. B. F. Skinner advanced the �ield of behaviorism by explaining how reinforcement and punishment shape behavior. More modern learning theory acknowledges the importance of cognitive and social variables in learning. Albert Bandura famously demonstrated that we also learn through observation and cognitive assessments.

Cognitive Theories

Jean Piaget is the most in�luential �igure in the study of cognitive development and perhaps all of cognitive psychology. He constructed the �irst comprehensive theory of how thinking processes emerge, identifying discrete stages. Lev Vygotsky emphasized that the key to cognitive development rests in the context in which learning takes place. His contextual model includes a strong cultural component.

The information-processing theory is modeled on the computer and the way in which it takes in, stores, and uses information.

Systems Theories

The contemporary ecological systems model stresses the importance of the environment in development. Urie Bronfenbrenner constructed a model of interconnected systems that illustrated the many levels of in�luence on human development. Esther Thelen’s dynamic systems theory addresses the complexity of development while acknowledging the interaction of biology on momentary actions.

The Scienti�ic Study of Development

Like other sciences, developmental psychology is a scienti�ic endeavor. We must adhere to scienti�ic principles. Ethics in research can never be overlooked. Principles in research ethics include those to do no harm, provide informed consent, limit the use of deception, and protect privacy.

Descriptive and Correlational Research

Case studies, naturalistic observation, surveys, and correlational research illustrate the most common simple research designs. Each method has speci�ic strengths and weaknesses. Correlational research describes the strength of association between two existing variables. Because ages of research participants cannot be manipulated, correlations are a fundamental component of lifespan research literature.

Studying Change Over Time

Longitudinal design studies one or more individuals across time. Cross-sectional studies investigate people of different ages at the same time. Sequential designs combine longitudinal and cross-sectional cohorts, so results can be analyzed from multiple developmental perspectives. The sequential design attempts to solve the problem of cohort and historical effects, which exist when one group being studied has different experiences from another.

The Experimental Method

Though not always conducive to developmental research, the experimental method remains the standard for many kinds of scienti�ic endeavors. Research that employs the experimental method must clearly state the independent and dependent variables, operational de�initions, and potential extraneous variables. In the experimental method, individuals are typically assigned randomly to either the experimental or the control groups.

Becoming a Good Skeptic

Becoming a good consumer of research is acknowledging and understanding that what is “well known” or popular in the media is not always scienti�ically viable.

Critical Thinking and Discussion Questions 1. Children often play games in which they look for a hidden item and the person who hid the item responds to

the seeker’s behaviors by using words related to temperature (e.g., “warmer, warmer, hot, hotter, burning!”). What behavioral concept is applied in these situations?

2. How does Erikson’s view of development differ from early psychoanalytic views? 3. What major changes in scienti�ic thinking occurred when learning theory became more prominent? 4. Explain why Bronfenbrenner’s and Thelen’s theories are described as systems. 5. Identify differences of your generational cohort compared to other generations. Design a cross-sectional study

that might identify the effects.

6. Find an article on a news site that discusses a recent research �inding. You may need to also �ind the peer- reviewed source from which the report originated.

a. Identify the type of experimental design that was used. b. List the operational de�initions. c. Assess the �indings based on what you’ve read in this chapter and raise questions about the methods

and results.

Additional Resources Web Resources

American Psychological Association’s ethical standards in research http://www.apa.org/monitor/jan03/principles.aspx (http://www.apa.org/monitor/jan03/principles.aspx) BioMed Central, an open access resource for research http://www.biomedcentral.com (http://www.biomedcentral.com) Directory of Open Access Journals, an open access resource for research https://doaj.org/ (https://doaj.org/) National Center for Biotechnology Information, an open access resource for research (abstracts only)http://www.ncbi.nlm.nih.gov (http://www.ncbi.nlm.nih.gov) Society for Research in Child Development’s ethical standards in research http://www.srcd.org/about- us/ethical-standards-research (http://www.srcd.org/about-us/ethical-standards-research)

Further Research

Bandura, A. (1977). Social learning theory. New York: General Learning Press. Bronfenbrenner, U. (1979). The ecology of human development. Cambridge, MA: Harvard University Press. Erikson, E. H. (1950/1993). Childhood and society. New York: Norton. Pavlov, I. P. (1927). Conditioned re�lexes: An investigation of the physiological activity of the cerebral cortex. Translated and Edited by G. V. Anrep. London: Oxford University Press. Retrieved from http://psychclassics.yorku.ca/Pavlov/ (http://psychclassics.yorku.ca/Pavlov/) Piaget, J. (2006). The origin of intelligence in the child. New York: Routledge. (Originally published 1953.) Schaie, K. W. (1994). Developmental designs revisited. In S. H. Cohen & H. W. Reese (Eds.). Life-span developmental psychology (pp. 45–64). Hillsdale, NJ: Erlbaum. Vygotsky, L. (1978). Mind and society: The development of higher psychological processes. Cambridge, MA: Harvard University Press.

Key Terms

anecdotal evidence A person’s story or limited examples being used to generalize and support conclusions in a way that is not in keeping with the scienti�ic method.

bioecological systems theory Bronfenbrenner’s theory that uses a contextual approach to explain development by examining a number of environmental systems simultaneously.

case study A study that investigates outcomes of one person.

chronosystem The social and historical context in the bioecological systems theory.

classical conditioning Associative learning that takes place when a neutral stimulus is paired with a stimulus that naturally elicits a response.

cohort effect

Differences in one group compared to another that are due to common social or historical experiences within each group.

control group In the experimental method, the comparison group that receives no treatment. Contrast with experimental group.

correlation coef�icient A number ranging from –1.0 to +1.0, representing the strength and direction of a relationship between two variables.

correlational research Attempts to describe the strength of a relationship between two variables.

cross-sectional study Research that concurrently tests individuals across different ages.

dependent variable (DV) The variable being measured in an experiment.

descriptive research Research that focuses on gathering, analyzing, and reporting information.

dynamic systems theory A theory that explains development by the interaction of the mind, body, and social environment, which creates an integrated, dynamic system.

ego In psychoanalytic theory, the part of the personality that operates on the reality principle and serves as a mediator between the id and the superego.

empirical research The systematic, veri�iable acquisition of information.

exosystem The community and socioeconomic variables in the bioecological systems theory.

experimental group (or treatment group) In an experiment, the group that receives the effect of the independent variable. Contrast with control group.

experimental method Research method that involves manipulating (independent) variables to measure their effect on other (dependent) variables.

extinction The gradual modi�ication of behavior that transpires when the conditioned behavior (either operant or classically conditioned) is no longer reinforced and thus no longer occurs.

extraneous variables Variables not accounted for that can affect the outcome of an experiment.

hypothesis A scienti�ic prediction.

id According to Freud, the part of the personality that is concerned only with seeking pleasure.

independent variable (IV) The variable being manipulated in an experiment.

information-processing theory

A theory that compares human cognitive development to a computer in the way that they take in, store, and use information.

learning theory A psychological approach that emphasizes the study of thoughts, feelings, and actions that can be observed.

longitudinal study A developmental research design whereby information about the same persons is recorded at different time intervals.

macrosystem The cultural context in the bioecological systems theory.

mesosystem The component of the bioecological systems theory that provides the connection among various components of a child’s microsystem.

meta-analysis A research and statistical review that combines results from multiple studies.

microsystem In the bioecological systems theory, the context that has a daily impact on the person.

modeling In social learning theory, the copying of behavior after observation. Also known as imitation.

multivariate analyses Research designs that study a number of variables simultaneously.

naturalistic observation The study behavior in a natural setting, without concurrent manipulation.

negative correlation In research, when an increase in one variable is associated with a decrease in the other. Contrast with positive correlation.

observer effect In an experiment, when people who are being observed act differently because of their knowledge of being observed.

operant conditioning Learning as a result of reinforcement or punishment.

operational de�inition The speci�ic de�inition of a variable in an experiment.

placebo A benign pill or procedure that appears to be the same as the treatment but has no known scienti�ic effect.

placebo effect A positive effect of treatment that is due to the person’s belief, not the condition of the treatment.

positive correlation In research, when two variables move in the same direction as each other. Contrast with negative correlation.

psychoanalytic theory Freud’s theory that early in�luences become unconscious motives that underlie and guide behavior.

psychosexual development

A part of the psychoanalytic perspective that identi�ies �ive speci�ic stages of development. Each stage corresponds to a speci�ic body part, each of which is a source of sexual energy.

punishment In learning theory, a consequence that decreases the chance that a behavior will be repeated.

random assignment In an experiment, when participants are assigned to groups based on chance, without any order or planning.

reinforcement In learning theory, a consequence that increases the chance that a behavior will be repeated.

representative sample A subgroup of the population that is assumed to have the same characteristics as the population.

response bias An individual’s tendency to respond in a certain way regardless of the question being asked.

sequential study Combines the features of longitudinal and cross-sectional designs.

shaping The gradual modi�ication of behavior by the reinforcement of successive behaviors that get closer and closer to a target.

social-cognitive theory Bandura’s theory that suggests that the environment and cognition interact to produce behavior, rather than simply reinforcement and punishment.

statistical signi�icance Refers to results from research that are not due simply to chance occurrence.

superego In Freudian theory, the part of the personality that incorporates societal standards of right and wrong, and opposes the impulses of the id.

surveys Also known as self-reports, generally a questionnaire form that researchers use to obtain a great deal of information at relatively minimal cost and time.

theory In developmental psychology, principles formulated to account for how developmental changes occur.