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Importantly, Baumrind’s findings may be culture‐specific, as deleterious outcomes in children with authoritarian parents in cultures in which this is the norm (e.g., China) have not always been found.

Physical Development

      From the moment of conception, physical development in humans occurs quickly and continues into adulthood. These processes develop fairly similarly across individuals, with the exception of a few differences. In this section, we discuss brain and motor development, along with puberty and problems in physical development.

      Prenatal Development

      The process of physical development begins before birth. Soon after conception, the single cell formed by the union of the sperm and egg begins to multiply at a fast pace. Over the course of the following weeks, tissues, organs, and structures begin to form, and the developing fetus takes the shape of a human being. Prenatal development occurs during three phases: the germinal stage (the first two weeks), the embryonic stage (second to eighth week gestation), and the fetal stage (ninth week to birth). Physical development occurs rapidly during the embryonic stage, when most organ systems are rapidly established and a neural tube begins to form, as well as during the fetal stage, during which the remaining organs and extremities continue to mature until birth. During the fetal stage, the fetus begins to move and the sensory systems begin to develop. Around seven months gestation, a fetus is able to respond to sound and light, and by birth, other sensory abilities become fully functional.

      Brain Development

      Over the course of the first few months and years of life, various skills and competencies improve at an impressively rapid rate. Many of the changes that we observe in human development happen in response to changes in the brain. Even before we are born, the brain and central nervous system support basic sensory and motor functions. Once born, rapid brain development occurs and continues well into adolescence.

At birth, the brain contains most of the information‐transmitting cells—also known as neurons—that it will ever have. Yet, the brain becomes four times larger by adulthood, with much of that growth occurring during the first few years of life (Groeschel et al., 2010). Processes that account for such growth in the size of the brain include synaptogenesis (the process of synapse formation between neurons) and myelination (the formation of myelin sheaths that allow for the increase in speed of electrical transmissions between neurons).

      Additionally, certain areas of the cerebral cortex—the brain’s outermost layer and most complex system—are specialized for certain functions. For example, the occipital lobe is primarily involved in visual processing; memory, visual recognition, and emotional/auditory processing occurs in the temporal lobe; spatial awareness and sensory processing are associated with the parietal lobe; and, the frontal lobe of the brain is responsible for humans’ ability to organize and plan ahead. As the brain continues to develop, connections between neurons become more efficient, and repeated stimulation enables the development and adjustment of humans’ physical and cognitive capacities.

      Motor Development

      At one time it was presumed that our brain had a predetermined sequence of motor development that would enable certain physical abilities to activate according to a predetermined timeline. However, this belief is now considered to be too simple. Instead, Thelen (2005) introduced the dynamic systems theory (DST), which supports the idea that motor development is influenced by an individual’s interaction with their environment, thereby suggesting that there are multiple factors involved in the speed and sequence of motor development. Developmental norms have been established to understand large samples, but individual differences are present and are important to consider when attempting to determine what is normal versus abnormal motor development.

      Much of the research on motor development has focused on the development of fine motor skills, which involve the development and coordination of the small muscles of the body, and gross motor skills, which involve the large muscles of the body and allow for locomotion to occur. As infants and children grow, both their fine and gross motor skills are fine‐tuned through various experiences in a predictable progression, although the timing of these skills varies.

      PUBERTY

Puberty, which occurs during adolescence, is one of the most significant changes in a human’s physical development. This biological process signifies a human’s physical and sexual maturation, as individuals become capable of reproduction during this developmental period. Puberty begins with a chemical signal from the hypothalamus, which directs the pituitary gland to start producing more growth hormones. Testosterone and estrogen play an important role in the development of sex characteristics in males and females, respectively. This maturation process can vary by individual and generally takes three to four years to complete. Increases in both height and weight occur in both sexes during the growth spurt. Primary sex characteristics include the reproductive organs (e.g., sperm‐producing testes in males and egg‐producing ovaries in females), while secondary sex characteristics include the outward physiological indicators or traits of sex (e.g., breasts and facial hair) that distinguish males from females, but are not involved in sexual reproduction. Puberty is thought to cause social reorientation in adolescents, as well as engagement in high‐risk behaviors.

Cognitive Development

      An Overview of Cognitive Development Across Domains

      Huge changes occur in humans’ cognitive capabilities over the course of infancy, childhood, and adolescence. However, cognitive—or intellectual—development does not proceed in the same way or at the same pace for everyone. While an individual’s cognitive abilities can confer risk or protection for psychopathology, as you will see in the subsequent chapters, it is important to note that the abilities described below interact with the child’s environment, demonstrating how individual and contextual factors interact in developmental psychopathology.

       Memory

      A huge literature is devoted to characterizing children’s memory development and mnemonic capabilities. Research suggests that even very young children are able to perform quite well on a variety of memory tasks, but that there are also many age‐related differences in children’s memory abilities, including in short‐term, working, and long‐term memory. These age‐related differences are frequently attributed to the maturation of basic processes in the brain that are involved in the encoding, storage, retrieval, and reporting of information, as well as other contextual factors such as level of prior knowledge and the way in which parents structure conversations with their children (Ornstein & Haden, 2001).

       Language

Humans appear to be born with a brain for language, as newborns are able to distinguish between phonemes from all the world’s languages at birth (although this ability becomes extinct by the end of the first year of life), and there are special structures in the brain that, when damaged, severely affect language production (Broca’s area) and language comprehension (Wernike’s area). Despite our biological and genetic predisposition to learn language, there are also environmental influences of language learning. The environmental key to language is best illustrated when examining language development in children raised in language‐impoverished environments (e.g., extreme neglect).

      Generally, language acquisition proceeds through four universal stages. In the phonological stage infants learn how to segment strings of speech into meaningful units. During semantic development, infants and children learn the meanings of words and word combinations; children’s first words usually develop by 12 months and at 18 months many infants undergo a vocabulary spurt in which they rapidly learn the meaning of many new words. In the third stage, known as the stage of grammar

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