Child Development Final Exam Comprehensive Review Notes - Biological and Cognitive Perspectives
Final Exam Structure and Biological Foundations of Heredity
The final exam for this child development course is divided into four primary categories designed to focus study efforts: the biological perspective, the cognitive perspective, the social perspective, and a smaller section on research methods. Although the categories are functionally the same size, the biological perspective covers material scattered throughout the textbook, as physical development is a recurring theme. The study of development begins with the genetic code, where the functional unit of heredity is identified as the gene. Genes themselves are composed of smaller units referred to as amino acids, nucleotides, or nucleic acids, depending on the scientific context. These genes represent the "words" of the hereditary language, such as instructions for blond hair, curly hair, dark skin, or straight hair. These genes are carried by larger molecules with double phosphate backbones known as DNA (Deoxyribonucleic acid). The largest molecules of our genetic language are the chromosomes, of which a typical person possesses pairs. Variants of a specific gene are called alleles. In this course, the primary focus is on dominant and recessive allelic interactions. A dominant gene is described as "pushy" or "bossy" and will manifest as a physical characteristic if present in the genome. Conversely, recessive instructions are weaker and only manifest in the phenotype if the individual is homozygous for that trait.
Meiosis, Sex Determination, and Genetic Disorders
Before conception, a unique type of cell division known as meiosis occurs specifically for the production of gametes, which include the egg and sperm. The result of the fertilization process or conception is the zygote. Within the genome, the rd pair of chromosomes is considered the sex-determinant pair. The feminizing designation for this pair is typically , where one is inherited from each parent. The masculinizing chromosome of the pair is the chromosome, resulting in a typical male designation of . Sex-linked disorders refer to diseases or conditions where the gene responsible is located on a specific sex chromosome, most commonly the . Disorders such as hemophilia and color blindness affect men more frequently than women because the chromosome is smaller and lacks much of the genetic information found on the chromosome. Consequently, an male lacks a second chromosome to serve as a "backup" in the event that their single chromosome contains damaged or missing information.
Stages of Prenatal Development and Biological Support Systems
Prenatal development consists of three distinct stages. The first stage is the germinal or zygotic stage, which lasts for the first weeks post-conception. The second stage is the embryonic stage, spanning from to weeks. It is during this embryonic stage that organs begin to form, and it is also the period when the majority of miscarriages occur due to the complexity of organogenesis. The final, long-term stage is the fetal stage. The term for the minimum gestational age required for a fetus to survive outside the womb is the age of viability, which occurs during the fetal stage. After implantation into the uterus during the embryonic period, several support structures form. These include the amniotic sac (sometimes called the amnion), which contains amniotic fluid to protect the prenate. The umbilical cord feeds into the placenta, which is a specialized layer of tissue at the end of the cord that filters incoming nutrients from the mother and helps filter out harmful substances.
Cellular Differentiation and Neural Tube Defects
During early development, stem cells in the blastocyst divide into three distinct dermal layers. The mesoderm is the middle layer that eventually develops into muscle and bone. The endoderm is the layer that gives rise to soft organs, such as the lungs and the gastrointestinal (GI) tract. The ectoderm is the layer responsible for the development of the skin, hair, and, most importantly for psychology, the nervous system. The formation of the nervous system involves stem cells laying out in a sheet that folds over to create the neural tube. If the neural tube fails to close at the top near the brain stem, it results in anencephaly, a condition literally meaning "without head" where the fetus is missing parts of the brain stem, cerebellum, or hindbrain, making it non-viable. If the tube fails to close at the bottom, it results in spina bifida, where the spine is exposed and the bone fails to form over the nerves and blood vessels.
Environmental Hazards and Chromosomal Abnormalities
Teratogens are defined as environmental agents—such as chemicals, diseases, or drugs—that harm or redirect prenatal development. Although traditionally viewed in a prenatal context, the term can be applied to postnatal development, as substances like lead in drinking water continue to affect the developing minds of young children and even adults. In addition to environmental factors, chromosomal disorders can impact development. Down syndrome, also known as Trisomy , occurs when there is extra genetic information on the st pair of chromosomes. Other disorders occur on the rd pair. Klinefelter syndrome is characterized by an genetic makeup. Turner syndrome occurs when there is missing chromosomal information, typically represented as an or "X not" makeup; individuals with Turner syndrome present as female but often face reproductive challenges.
Patterns of Growth, Motor Skills, and Brain Development
Growth follows two primary patterns: cephalocaudal (from head to tail) and proximodistal (from the core or "near" to the extremities or "far"). In the transition to early childhood, differences in motor skills emerge between boys and girls. Around ages or , boys tend to excel in gross motor skills, which involve large muscle movements and explosive activities, potentially due to testosterone or social encouragement. Girls tend to advance faster in fine motor skills, which involve deft, fine-tuned movements. In adolescence, puberty marks the activation of the reproductive system. For boys, the first release of semen is known as semenarche. Regarding brain development, the brain increases in size despite not adding more neurons. This is explained by two processes: myelination and blooming. Myelination involves the growth of the myelin sheath, a fatty white substance (white matter) that wraps around the axon of a neuron to increase communication speed. Blooming, or dendritic branching, refers to neurons getting bigger and dendrites expanding through repeated use. Neurons consist of dendrites, which are branch-like extensions that receive signals, and the axon, which is the long extension that sends signals. The space between neurons is known as the synapse.
Sensation, Perception, and Visual Development
Sensation is defined as the ability to detect stimuli in the physical environment, whereas perception is the mind's ability to interpret, understand, and make sense of that sensory information. In visual development, infants are born with poor vision. Visual acuity is the ability of the eye to detect fine detail. Visual accommodation is the ability of the eye to change focus between near and far objects. Many children enter school with poor accommodation, sometimes resulting in a diagnosis of nearsightedness. If not corrected, these children may struggle to engage in class and could be misdiagnosed with conditions like ADHD (Attention-Deficit/Hyperactivity Disorder) simply because they cannot see the board.
Piaget’s Cognitive Stages: Sensory Motor and Pre-operational
Jean Piaget’s stage theory outlines cognitive development through various ages. The first stage is the sensory motor stage ( to years), characterized by milestones such as locomotion (intentional, autonomous movement) and object permanence (the ability to hold a mental representation of an object when it is not physically present, often tested via games like Peek-a-boo). The third milestone is symbolic use, with language being the best example. The second stage is the pre-operational stage ( to years). Milestones here include overcoming egocentrism—the inability to take on other perspectives because the child’s new sense of self is so powerful. Another characteristic is centration, where a child's attention is overly focused on superficial or incorrect elements of a problem, preventing them from solving complex tasks.
Piaget’s Cognitive Stages: Concrete Operational and Attention Systems
The third stage is the concrete operational stage ( to approximately or years). A hallmark of this stage is the development of mental operations, which is rule-based thinking characterized by reversibility. Children in this stage move toward decentration, allowing them to multitasking and see past superficial details to more abstract aspects of a problem. Specific abilities include seriation (arranging data sets along a rule, such as organizing toys from favorite to least favorite), transitivity (inferring new relationships based on existing ones), and class inclusion (understanding categorical relationships). In the cognitive perspective, attention systems also evolve. Selective attention is the intentional focus on specific stimuli while excluding others. Sustained attention is the ability to maintain that focus over time. Divided attention, or multitasking, is the ability to think about more than one thing at once. Divided attention is resource-intensive and is the last to emerge and the first to decline in old age. Joint attention refers to attention shared by two people, such as an infant following a mother's gaze out a window.
Questions & Discussion
The professor interactively reviewed names of the students in the class, identifying Anna, Bryn (or Briggs), Kylie, Melody, and Lauren. There was a discussion regarding an impromptu extra credit opportunity involving a survey for Andy’s research methods class.
Question: "I filled it out in Intro to Psych, so do I just, like, show you I filled it out?" Response: "On Friday, bring me the phone, show me that, you know, you filled it out. Hopefully, it is on your phone, or maybe screenshot it. Four points of extra credit for those that participate."
The professor noted there were two different QR codes for different sections, but encouraged students to focus on the one with fewer responses to help the research project. The session concluded with the plan to cover the social and research methods sections in the next meeting.