William Kessen was born in Key West, Florida, in 1925. Kessen's many honors included memberships in the Society of Experimental Psychologists and the American Academy of Arts of Sciences. The only child of a ship's engineer and a homemaker, his journey toward Yale began as a bespectacled youth who declared himself a Roosevelt liberal. The first in his family to attend college, Kessen…
Klinefelter's syndrome (genotype 47, XXY) is a chromosomal anomaly in which affected males have an extra X chromosome. It occurs in 1:1,000 to 1:2,000 newborn males and has been detected in .003 percent of spontaneous abortions. This condition generally arises from failure of chromosomes to separate properly during meiosis. Specifically, an egg cell bearing an additional X chromosome (or a …
Born in Broxville, N.Y., Lawrence Kohlberg was a professor of Education and Social Psychology at Harvard University and is best known for his influential work in moral development and moral education. As a young man, Kohlberg served in the U.S. Merchant Marine after World War II. He then volunteered to help smuggle Jewish refugees out of Europe and through a British blockade into British-controlle…
Laissez-faire is a French term meaning "to let people do as they please." Applied to parenting, the term refers to a permissive style in which parents avoid providing guidance and discipline, make no demands for maturity, and impose few controls on their child's behavior. Permissive parents allow their children to make their own decisions regarding matters such as mealtimes, b…
The Language Acquisition Device (LAD) is a hypothetical brain mechanism that Noam Chomsky postulated to explain human acquisition of the syntactic structure of language. This mechanism endows children with the capacity to derive the syntactic structure and rules of their native language rapidly and accurately from the impoverished input provided by adult language users. The device is comprised of …
Mike (age five years, discussing the game of baseball): Mom, did you know that baseball games need a vampire? Mom: A vampire? Mike: Yes, the vampire stands in back of the catcher and catches any of the balls that the catcher misses. Joshua (age three, picking up the book Sleeping Beauty): Let's read Sleeping Buddha. Child (age four): Nobody doesn't likes me. Parent: You mean, "…
Latchkey children are defined by the authors of The Facts on File Dictionary of Education as: "School-aged children who are typically unsupervised after school hours because of working parents and, therefore, who carry a house key to let themselves in after school." This straightforward definition overlooks children who have a parent at home, but the parent offers little or no approp…
Lead is an environmental toxin that can cause mental retardation, brain damage, or death in children. Young children are particularly at risk because they can accidentally eat leaded paint chips or breathe lead-contaminated dust. Although lead-based paint for household use has been banned in the United States since 1977, deteriorated older houses remain important sources. Once inside the body, lea…
Learning can occur in a variety of manners. An organism can learn associations between events in their environment (classical or respondent conditioning), learn based upon the reinforcements or punishments that follow their behaviors (operant or instrumental conditioning), and can also learn through observation of those around them (observational learning). Learning principles are of particular im…
It is estimated that 5 percent to 10 percent of school-age children and adolescents have learning disabilities (LDs), with some estimates approaching 17 percent. LDs fall on a continuum and range in severity from subtle to marked impairment. A substantial number of learning-disabled students receive special education services. In 1975 the U.S. Congress enacted the Education for All Handicapped Chi…
Born in Somerset, England, John Locke was a noted philosopher—the first of the British empiricists— political adviser, and physician. As a student at the Westminster School, Locke endured the typical mid-seventeenth-century educational regimen reserved for adolescent boys: strict adherence to rules, severe punishments, and rote memorization of both the principles of grammar and large…
Mainstreaming is the original term used for the requirement under the Individuals with Disabilities Education Act (IDEA) that children with disabilities be educated in the least restrictive environment (LRE). Under IDEA, states must assure that, to the maximum extent appropriate, children ages three to twenty-one who have disabilities have access to the general education curriculum and are educate…
Malnutrition refers to any condition caused by excess or deficient food energy, protein, or nutrient intake, or by an imbalance of nutrients. Nutrient or energy deficiencies are classified as forms of undernutrition; nutrient or energy excesses are forms of overnutrition. Malnutrition can take two forms: primary, due to a lack, excess, or imbalance of a nutrient or nutrients in the diet; and secon…
Marasmus is a form of emaciation and wasting in an infant due to protein-energy malnutrition. It is characterized by growth retardation in weight more than height so that the head appears quite large relative to the body. There is a progressive wasting of subcutaneous fat and muscle so that the skin appears loose. Severe prolonged marasmus may result in permanent retardation. Marasmus is common in…
Abraham Maslow is best known for his work on a theory of motivation and for his enormous impact on humanistic psychology, also known as the third force in psychology. Born April 1, 1908, in Brooklyn, New York, to Russian-Jewish immigrant parents, Maslow was the oldest of seven children. He attended City College of New York and Cornell University before transferring, in 1928, to the University of W…
Extremes of maternal age are associated with adverse outcomes in pregnancy. Age at the time of delivery of less than sixteen years or greater than thirty-five years meets the criteria for this definition. Young women have a higher incidence of premature delivery, high blood pressure, and small infants. In women over age thirty-five, chronic diseases such as diabetes and high blood pressure become …
A comprehensive definition of maternal, or reproductive, health was one of many important contributions of the landmark United Nations International Conference on Population and Development (ICPD) held in September 1994 in Cairo, Egypt. The ICPD definition stated that "Reproductive health is a state of complete physical, mental, and social well-being and not merely the absence of disease or…
Arnold Gesell, a psychologist, pediatrician, and educator in the 1940s, was very interested in child development. From his numerous observations of children, Gesell formulated a theory known as maturation. This theory stated that developmental changes in a child's body or behavior are a result of the aging process rather than from learning, injury, illness, or some other life experience. Ge…
Born in Birmingham, Alabama, in 1899, Myrtle McGraw was a pioneer in the study of child growth and development in the 1930s and 1940s. She is best known for her experimental study of twins Johnny and Jimmy Woods. Her studies demonstrated that early stimulation accelerates motor development, enabling infants to learn challenging skills, such as swimming and roller skating, and to solve problems tha…
When a marriage is dissolving, the spouses must reach agreement on property division, spousal support, child custody, and parental visitation. With the advent of "no-fault" divorce laws, the process of reaching a settlement between the divorcing spouses has become increasingly private. The high costs associated with the more public and formal legal processes has led many divorcing sp…
Two types of nuclear division, mitosis and meiosis, occur in cell biology. Most human cells (called diploid cells) are formed through mitosis and contain forty-six chromosomes in twenty-three matched pairs. By contrast, meiosis produces haploid cells, each containing a single set of twenty-three unpaired chromosomes. Sex cells (sperm and ovum) are haploid. Prior to meiosis, DNA is replicated withi…
Memory is involved in almost every aspect of children's behavior, from everyday occurrences such as finding a misplaced toy, through the routine demands of learning formulas for a math test, to emotionally charged experiences such as explaining why a particular punishment was unfair. In this overview of memory development, the structure of the memory system will be examined, different types…
Menarche refers to the first menstrual flow experienced by a girl during puberty. Menstruation means that the physiological and hormonal changes underlying reproductive processes have matured sufficiently to produce the endometrial lining of the uterus, which is sloughed off at the end of the menstrual cycle if implantation of a fertilized ovum has not occurred. Menarche typically occurs after oth…
The menstrual cycle is a periodic flow of blood and cells from the lining of the uterus in human females and the females of most other primates, occurring about every twenty-eight days. The beginning of menstruation, or menarche (the first menstrual period), typically starts between the ages of ten and seventeen and is a sign of readiness for childbearing. During each cycle, the lining, or endomet…
Mental age refers to an age-normed level of performance on an intelligence test, and it became a popular way of referring to "mental level" as measured by the Binet-Simon Scale of 1908. The Binet-Simon Scale identified the academic skills typical of specific age groups. In 1912 William Stern used chronological age as a denominator to be divided into mental age, resulting in an intell…
Children's mental health problems have emerged from a long history of misunderstanding and neglect to become the central concern of an active group of researchers and practitioners. The last few decades of the twentieth century witnessed an explosion of knowledge about the nature of disorders that affect children, their frequency of occurrence, their developmental course, and the effectiven…
Mental retardation (MR) is a developmental disability, defined by looking at three aspects of a child. IQ score, adaptive functioning, and the age of onset determine where a child lies in the continuum of mental retardation. A numerical component of MR is defined by an IQ intelligence test. An IQ test measures and predicts how well individuals learn in their environment. The average IQ score of a …
If cognition is defined as the way we think and process information, then metacognition can be defined as the way we think about our own thoughts. In other words, metacognition is thinking about thinking. American psychologist John Flavell believes that metacognition consists of metacognitive knowledge and metacognitive experiences. Metacognitive knowledge can be knowledge about the way you or oth…
When a researcher decides to study children, the task usually begins by choosing a topic or behavior to study and then focusing on a basic method that will allow the information to be gathered in the most efficient and effective manner. Researchers of child development have a variety of research methods from which to choose. These methods differ in important ways. For example, in a case study, the…
A midwife is a person, usually a woman, who assists other women in giving birth. Typically, this assistance extends throughout pregnancy, labor, delivery, and the newborn period. Midwives focus on delivering healthy babies in as natural a manner as possible; they also provide health counseling to mothers and families. Although obstetricians and midwives have much knowledge and experience in common…
Milestones of development are major turning points in childhood that help organize or direct other aspects of a child's development. Milestones occur in every area of development: physical and motor, social and emotional, and cognitive. Almost everyone experiences these environmental (e.g., nutrition and culture) factors. Not reaching a milestone or an extreme variation in timing may have a…
Human development is a complicated affair, progressing as the result of the continuous interaction of biologic and environmental factors. It is for this reason that no two people are exactly alike, not even identical twins. Despite such variability, there are aspects of development that are predictable, such that children throughout the world develop certain abilities and characteristics at about …
Miscarriage is a synonym for "spontaneous abortion" or "spontaneous pregnancy loss." A miscarriage occurs because of an abnormal fetus (usually within the first twelve weeks) or disruption of the uterus as a safe environment (more prevalent after thirteen weeks). Miscarriages are common, occurring in up to 19 percent of pregnancies. Miscarriage usually leads to vaginal …
Mitosis is the stage of the cell cycle at which chromosomal division occurs. This division precedes cytokinesis, or cell division, which leads to two daughter cells with identical nuclear DNA content. Between mitotic events, chromosomal DNA is replicated during the synthesis stage of the cell cycle. The process of mitosis is required whenever a somatic cell divides. In contrast to meiosis, which o…
The Montessori Method is a system of education based on the beliefs of Maria Montessori. The most critical components of her method include the Maria Montessori (right) created a system of education based on skill development in specific areas, including practical living and language. (AP/Wide World Photos) prepared environment and the teacher. The Montessori classroom is usually divided in…
During the last half of the twentieth century, perceptions of increased school violence within the United States renewed public concern for children's moral development. The study of moral development includes the way individuals reason about morality, the emotions associated with morality, the actions or behavior demonstrating morality, and the socialization or teaching of morality. Morali…
Speech directed toward infants and young children displays special characteristics, such as heightened pitch, exaggerated intonation, and increased repetition of words and clauses, that differ from the speech adults use with one another. Such "motherese" or "infant-directed talk" is typical of fathers as well as mothers, nonparents as well as parents, and across diverse…
