Lesson 2.2

    Problems and Solutions in Research

    ESSENTIAL QUESTION How do psychologists gather information?


    Have you ever thought about the different factors that might affect your score on a test? Perhaps you think you will do poorly because you did not sleep well the night before. Maybe the chairs are uncomfortable. Research results can be influenced in similar ways. Psychologists must be aware of such influences and try to reduce or eliminate them.

    Avoiding a Self-Fulfilling Prophecy

     Why must experimenters keep their own expectations from influencing their experiments?

    A math teacher thinks a particular student will be above average in algebra because the student’s older sister excelled in the class. The student thrives under the extra attention and praise that the teacher gives him. This is what we mean by a self-fulfilling prophecy. A self-fulfilling prophecy involves having expectations about a behavior and then acting in some way, usually unknowingly, to carry out that behavior. In everyday life, we consciously or unconsciously make our expectations known to others. We give cues, such as nodding and raising our eyebrows. Others pick up on those cues and act as expected. Psychologists must be aware of such cues when conducting experiments. They must not allow their expectations to influence their results. In this lesson, we will examine common problems psychologists confront in research.


    Single- and Double-Blind Experiments

    Suppose a psychologist wants to study the effects of a tranquilizer drug. She might give the drug to an experimental group and a substitute drug that has no effect to a control group. The next step would be to compare their performances on a series of tests. This is a single-blind experiment. The participants are “blind” because they do not know if they have received the real drug or the substitute. If the participants taking the substitute report feeling its effects, it means their expectations have played a role and they felt the effects because they believed they were taking a tranquilizing drug, not because of the drug itself.

    In another scenario, the researcher will not know who takes the drug or the substitute. She may, for example, ask the pharmacist to number rather than label the pills. Only after she scores the tests does she go back to the pharmacist to learn which participants took the tranquilizer and which took the substitute. This is a double-blind experiment. Neither the participants nor the researcher knows which participants received the drug. This eliminates the possibility that the researcher will unconsciously find what she expects to find about the effects of the drug. As a consequence, the researcher remains free of bias.

    The Placebo Effect

    When researchers evaluate the effects of drugs, they must always take into account a possible placebo effect. The placebo effect is a change in a patient’s physical state that results solely from the patient’s knowledge and perceptions of the treatment. The placebo is a type of treatment, such as a drug or injection, that resembles medical therapy but has no actual medical effects. In one double-blind study, researchers divided hospitalized psychiatric patients into two experimental groups and a control group. The experimental groups received either a “new tranquilizer” or a “new energizer” drug. The control group received no drugs. After six weeks the researchers evaluated the experimental groups. Fifty-three to eighty percent of the experimental groups reported that they had benefited from the drugs. Yet all the drugs were placebos. The participants had reacted to their own expectations about the effects of the drugs. Neither the researchers nor the patients were aware that the drugs were placebos until after the experiment. The Milgram Experiment

     Why can the Milgram experiment be classified as a single-blind experiment?

    Stanley Milgram wanted to determine whether participants would administer painful shocks to others when an authority figure instructed them to do so. Milgram studied 1,000 males, including college students and adults in various occupations. He told them he was studying the effects of punishment on learning.

    Milgram introduced each volunteer “teacher” to someone posing as a learner. The teacher watched the learner try to recite a list of words that he supposedly had memorized. Each time the learner made a mistake the teacher was ordered to push a button to deliver an electric shock. The teachers were told that the shocks would gradually increase from mild to a dangerous 450 volts. The teachers did not know the shocks were false because the learners displayed pain and begged to end the shocks. Although the task seemed difficult for them, 65 percent of the volunteers pushed the button until the shocks reached maximum severity. The results implied that individuals could easily inflict pain on others if directed by an authority figure. Later, Milgram informed the volunteers that there had been no shocks. Milgram’s experiment was a single-blind experiment because the participants did not know they were not administering a shock. Critics raised the following questions. How would you feel if you had been one of Milgram’s participants? Did Milgram violate ethical principles? Was Milgram’s deception appropriate? Did the information gained outweigh the deception? Today, before the start of any experiment, the researcher is required to submit a plan to a Human Subjects Committee that approves or rejects the ethics of the experiment.

    Researchers at Swarthmore College hypothesized that Milgram’s findings were due, in part, to the fact that his participants were mostly middle-aged, working-class men. Most had probably served in the military during World War II and thus had experience obeying orders. Young, liberal, highly educated Swarthmore students would obey less. Yet, surprisingly, 88 percent of the Swarthmore undergraduates administered the highest level of shock!

    It is important to remember that the Milgram experiment was conducted prior to the development of the APA Code of Ethics. In fact, the experiment itself was a major reason pressure grew to develop the code.



    Lesson 1

    Physical, Perceptual, and Language Development

    ESSENTIAL QUESTION How do our abilities change from birth to childhood?


    Human development is remarkable for the speed with which it takes place. In a mere three years, a human will move from a one-celled organism to a living, breathing, responsive child fully capable of walking, talking, thinking, and making its likes and dislikes clearly known. These complex and fascinating first steps into life involve numerous changes in physical and mental development.

    Fetal and Newborn Development

     How are the capabilities of newborns measured?

    Developmental psychology is the study of how humans mature and why they develop as they do. Developmental psychologists study the following main issues: continuity versus discontinuity, stability versus change, and nature versus nurture. Psychologists studying continuity versus discontinuity ask the question: How much developmental change occurs gradually over time, and how much occurs in a series of clearly defined steps, or stages? The question asked by psychologists studying the stability versus change issue is: Do various traits, such as shyness or extraversion, remain stable and consistent through life or do they change over time? Finally, on the question of nature versus nurture, psychologists ask: How much of development is the result of inheritance (heredity), and how much is the result of what we have learned?

    Some psychologists believe that most of our behaviors are the result of genetics or inheritance. Others believe that most of our behaviors are the result of experience and learning. Separating biological and environmental causes of behavior is very complicated. Usually behavior develops as a result of the interaction of both heredity and environment. For example, Attention Deficit Hyperactivity Disorder (ADHD), which leads to the inability of children to stay focused on tasks, is a developmental disorder that demonstrates the close relationship between biological and environmental causes of behavior.


    Fetal Development

    Human development begins long before an infant is born. Over the span of roughly 40 weeks, a fertilized egg develops into a newborn baby. This development is rapid and complex. By the end of the first week, the embryo consists of more than 100 cells. By Week 2, these first cells are no longer alike. They are developing into a variety of cell types, including bone, muscle, nerve, and blood cells. Arteries and veins are forming by the end of Week 2. By the end of Week 4, the embryo consists of millions of cells and has the beginnings of eyes, ears, a brain, and a face. The heart and nervous system also begin development.

    By the end of Week 5, the embryo has all its internal organs. The brain continues to develop during this period, and by Week 8 the number of nerve cells in the brain is increasing at the rate of 100,000 cells per minute. By the end of the first trimester, which is the first three months of development, the embryo is called a fetus and is continuing to grow at an amazing rate. At this time the fetus is about 3 inches long and looks like a tiny adult. The next several weeks are crucial as the organs develop and the fetus grows in size. Expectant mothers can feel strong movement and kicking—even hiccuping—inside them during the final stages of pregnancy. It is common for a fetus to suck its thumb, even though it has never suckled at its mother’s breast or had a bottle.

    Although protected in its mother’s womb, the developing fetus remains vulnerable to factors that can harm its growth. Environmental factors, such as the mother’s exposure to radiation, mercury, lead, or other contaminants, may damage the developing organs, particularly the brain. Exposure to diseases such as rubella, especially in the first month of pregnancy, can cause physical or mental damage in the early stages of the development of the embryo. In addition, a mother’s use of alcohol, drugs, or nicotine can harm the developing fetus. Fetal Alcohol Syndrome, producing physical and mental damage in the fetus and behavioral difficulties in childhood, is one of many possible results.

    Biological factors can affect the developing fetus, too. Some birth defects are caused by genetics. Conditions such as Sickle cell anemia, Tay-Sachs disease, and Down syndrome are all hereditary. Sickle cell anemia can lead to heart deformities. Tay-Sachs disease usually leads to death within three to four years after birth. Down syndrome produces varying levels of mental retardation. The developmental disorder ADHD seems to begin during fetal brain development; the brain scans of affected children are different from those of other children. The disorder may run in families, which suggests a genetic component, though its exact cause is not yet clear. Researchers continue to explore the possibility that some developmental disorders, such as ADHD, are the result of a combination of genetic, environmental, and physiological factors.

    Newborn Development

    While 40 weeks is the normal period needed for a human baby to develop, some are born before that time. If the baby is born before Week 37 it is considered premature. Although the baby’s organs are formed by Week 5, the next 35 weeks are needed for the organs to grow and develop to the point that the fetus can survive after birth. The more time these organs have to grow, the better the chance of a premature baby’s survival. Babies born as early as 17 weeks can survive, but they are more likely to have serious health difficulties. Because their organs are not fully formed, premature babies are subject to heart defects, respiratory problems, blindness, and brain damage. Hospitals with neonatal intensive care units are equipped to deal with the special needs of dangerously premature infants.

    Newborns have the ability at birth to see, hear, smell, and respond to the environment. These abilities allow them to adapt to the world around them. Psychologists have found that birth puts staggering new demands on a baby’s capacity, or ability, to adapt and survive. Newborns go from an environment in which they are protected from the world to one in which they are assaulted by it. From the moment it is born the newborn is confronted by bright lights, loud sounds, unfamiliar touches, and temperature extremes. The newborn is capable of certain automatic, coordinated movement patterns, called reflexes, that help them respond to their new environment. Reflexes can be triggered by the right stimuli. Many, but not all, infants are born with these reflexes. The grasping reflex, for example, is a response to a touch on the palm of the hand. Infants can grasp an object, such as a finger, with enough strength that they can be lifted into the air. Also vital is the rooting reflex. When alert newborns are touched anywhere around the mouth, they will move their head and mouth toward the source of the touch. In this way the touch of a mother’s breast on her newborn’s cheek guides the infant’s mouth toward her nipple. The sucking that follows such contact is one of the infant’s most complex reflexes. The infant is able to suck, breathe, and swallow milk twice a second without getting confused.

    How do we measure the capabilities of newborn infants who cannot speak or understand the questions of curious psychologists? One reasonable way to answer these questions is to take advantage of the things infants can do. What they can do is suck, turn their heads, look at things, cry, smile, and show signs of surprise or fright. The vigor of an infant’s sucking, the patterns of eye movements, and expressions of pleasure and displeasure are all closely tied to how the infant is being stimulated. By measuring these behaviors while stimulating the infant in different ways, we can infer how the infant perceives the world.

    Infants on average weigh 7.3 pounds at birth. Their weight can grow rapidly during their first year of life and on average infants can weigh as much as 20 or 25 pounds by the end of the first year. This first year also sees substantial growth in length. From birth, infants grow about 1 inch per month during their first year of life. By their first birthday, infants are on average 1.5 times longer than their length at birth. The changes that happen in the first years of life are substantial. In the space of two years, the grasping, rooting, searching infant will develop into a child who can walk, talk, and feed herself or himself. This transformation is the result of both maturation and learning.


    Infants will begin to lift their heads at about 3 months, smile at 4 months, and grasp objects at 5 to 6 months. Crawling appears at 8 to 10 months. By this time infants may be able to pull themselves into a standing position, although they will fall if they let go. They will begin to walk 3 or 4 months later, tentatively at first, but gradually acquiring a sense of balance. Psychologists call this complex growth process maturation. Maturation is as important to development as learning or experience, especially in the first years. Unless children are persistently underfed, severely restricted in their movements, or deprived of human contact and things to look at, they will develop more or less according to this schedule. Purely as a matter of efficiency, it is worthwhile to wait until an infant reaches maturational readiness before pushing that infant into mastering new skills. No amount of coaching will enable children to walk or speak before they are physiologically ready.

    The process of maturation becomes obvious when you think about walking. Infants lack the physical control walking requires. By the end of the first year, however, the nerves connected to the muscles have grown and the infant is ready to walk. By recording the ages at which thousands of infants first began to sit upright, to crawl, and to try a few steps, psychologists were able to develop an approximate timetable of maturation. This schedule helps doctors and other health professionals spot potential abnormalities. If a child has not begun to talk by the age of 2½ , a doctor will recommend tests to determine if something is wrong.

    One of the facts to emerge from this effort, however, is that the maturational plan inside each child is unique. The average infant starts walking at 12 to 13 months. Some, though, are ready at 9 months, and others delay walking until 18 months. Each infant also has his or her own temperament. Some infants are extremely active from birth and some are quiet. Some are cuddly and some are stiff. Some cry a great deal and some do not. Although no two infants are exactly alike and no two mature according to the same timetable, most infants progress through the same sequential steps. Identifying similarities and differences in growth patterns is one of the many challenges for developmental psychologists. Perceptual Development

    Newborns can do more than grasp and suck. They also look at their bodies and at their surroundings. In the early months of life, the human brain continues to develop, and external experiences directly influence changes in the infant’s perceptual development. That is, the newborn’s brain continues to “wire” itself in response to its environmental stimuli, such as light, color, and movement. Different areas of the brain develop as the infant matures to support different processes of perception, such as vision, hearing, taste, touch, and smell, as well as perception of movement, color, and depth. Auditory perception—especially voice recognition—is in place at birth, while brain areas implicated for vision continue to develop after the baby is born.

    In 1961 researcher Robert Fantz showed infants different faces and discovered that babies have a preference for looking at human faces and patterned materials. Infants also benefit greatly from being touched by their parents. A pair of experimenters devised the visual cliff to determine whether infants have depth perception. The visual cliff is a platform, part of which has a checkerboard pattern. The other part consists of a sheet of glass with the checkerboard pattern a few feet below it. This creates the view of a cliff like drop-off. Whereas very young infants seemed unafraid, older infants (6 months and older) who were experienced at crawling refused to cross over the cliff. The older infants had explored the world, apparently finding that drop-offs are dangerous. Also, researchers found that there were changes in the heart rates of very young infants as they would crawl farther, implying that newborns are born with some perceptual capabilities. Language Acquisition

     What steps are involved in learning language?

    Language and thought are closely intertwined. Both abilities involve using representations or symbols. We are able to think and talk about objects that are not present and about ideas that are not necessarily true. A child begins to think, to represent things to himself, before he is able to speak. The acquisition of language propels the child into further intellectual development.

    Many psychologists argue that language is a learned behavior, while others claim it is inborn. Some psychologists claim there is a critical period, or a window of opportunity, for learning a language. Humans may have a sensitive period early in life in which acquisition of language is easier.

    How Children Acquire Language

    In the beginning, infants and toddlers learn the signs of communication—whether by hand or by mouth. As they grow, they will slowly develop their vocabulary and understanding of grammar. During the first year of life, the average child makes many sounds, beginning mostly with cooing sounds. These sounds develop into a babble that includes every sound humans can make—Chinese vowels, African clicks, German rolled r’s, and English o’s. Late in the first year, the strings of babble begin to sound more like the language the child hears. Children imitate the speech of their family members, and are greeted with approval whenever they say something that sounds like a word. In this way children learn to speak their native language, though they could just as easily learn any other. The leap to using sounds as symbols occurs sometime early in the second year. The first attempts at saying words are primitive. “Ball” usually sounds like “ba,” and “cookie” may even sound like “doo-da.” The first real words usually refer to things the infant can see or touch. Often they are labels or commands (“dog!,” “cookie!”). By the time children are 2 years old, they have a vocabulary of 500 to 1,500 words. Near the end of the second year, they begin to join words into two-word phrases. From about 18 months to 5 years of age, children are adding approximately 5 to 10 words a day to their vocabulary.

    At age 2, though, a child’s grammar is still unlike that of an adult. Children use telegraphic speech such as “Where apple?” or “Daddy fall.” They leave out words or use the wrong verb tense but still get the intended message across to the listener. As psychologists have discovered, 2-year-olds already understand certain rules. They place words in the same order adults do. At first children imitate the correct verb form: “Daddy went yesterday.” Once children discover the rule for forming past tenses, they replace the correct form with sentences like “Daddy goed yesterday.” When the correct form appears, the child has shifted from imitation to rule-based language. By age 4 or 5, children have a several thousand word vocabulary.

    Scientists have long known that areas in the left hemisphere of the brain are used for learning how to speak and understand language. Several other areas of the brain are also involved in processing language. Studying babies who were born prematurely can begin to explain the brain’s role in language development. Children born prematurely may have a more difficult time with language as it becomes more complex. One study found that preterm babies can show normal language development until they are around age 2, while language is fairly simple. Research using brain imagery suggests that the brain can create neurological connections that help compensate for the babies’ early development. As language becomes more complex, however, it appears that the brain is limited in its ability to compensate. Animals and Language

    We have been able to learn much about language acquisition from animal research. Psychologists believe that chimpanzees develop at least as far as 2-year-old humans, as they will look for a toy or a bit of food that has disappeared. They can represent the existence of that toy or bit of food mentally. Can they be taught to “talk” about it? Beatrice and Allen Gardner raised a baby chimp named Washoe in their home and taught her to use the American Sign Language. At 3½ years of age, Washoe knew at least 87 signs that could represent words such as food, dog, and toothbrush. By age 5, Washoe used more than 160 signs. Chimpanzees have been trained on special typewriters connected to computers. One chimpanzee, Panzee, used a special computer keyboard with symbols to communicate with humans.

    The chimps use only some aspects of the human language. Chimps use words as symbols but do not apply grammatical rules. The ability to arrange symbols in new combinations to produce new meanings is especially well developed in the human brain. The rules for such organization of symbols are called grammar. Grammatical rules are what make the sentence “the rhinoceros roared at the boy” mean the same thing as “the boy was roared at by the rhinoceros.” It is in our unique ability to use such grammatical rules that we surpass the simpler language of the chimpanzee.