Intro & Basic Concepts.docx

**Lifespan Development** **Chapter 1: Basic Concepts and Methods** **Human development** is a field of study that examines the age-related changes in our physical bodies, behaviors, cognition, emotions, social interactions, and personalities. This field has been influenced by philosophers who, eve...

**Lifespan Development** **Chapter 1: Basic Concepts and Methods** **Human development** is a field of study that examines the age-related changes in our physical bodies, behaviors, cognition, emotions, social interactions, and personalities. This field has been influenced by philosophers who, even before the advent of the scientific method, provided various explanations for the differences they noticed among individuals of varying ages. These philosophical ideas continue to shape the field and form the basis for many contemporary beliefs about human development. [Early philosophers formulated their developmental theories based on spiritual authorities, overarching philosophical perspectives, and deductive reasoning]. Their primary focus was to understand why babies, despite their apparent similarities, grow up to exhibit significant differences. **Original Sin** The Christian doctrine of original sin, often linked to the 4th-century philosopher Augustine of Hippo, posits that humans are born with a selfish and stubborn disposition. Augustine advocated for a disciplined life to mitigate this inherent sinful tendency. Consequently, from this viewpoint, parents play a crucial role in helping children overcome their innate immoral inclinations by providing guidance and correction. **The Blank Slate** John Locke, a 17th-century English philosopher, proposed an empirical approach suggesting that a child's mind is a 'blank slate'. According to empiricism, humans have no inherent tendencies and all differences among individuals are due to their experiences. This perspective implies that adults can shape children as they wish. Therefore, the differences among adults are attributed to their varying childhood environments, rather than a struggle to overcome inherent tendencies, contrasting the original sin view. **Innate Goodness** The 18th-century Swiss philosopher Jean-Jacques Rousseau proposed the view of innate goodness. He believed that all humans are naturally good and seek growth experiences. According to Rousseau, children only need nurturing and protection to fulfill their potential. Good development occurs when the environment allows a child to nurture their own development without interference. Conversely, poor outcomes arise when a child's efforts to express their inherent goodness are obstructed. **The Study of Human Development Becomes a Science** The 19th century marked a significant shift in interest towards applying scientific methods to questions traditionally associated with philosophy. By 1930, psychology had established itself as a key contributor to the foundations of modern human development and started influencing daily child-rearing practices. **Darwin** Charles Darwin and his contemporaries believed that studying child development could shed light on human evolution. Many, including Darwin, maintained comprehensive records of their children's early development, known as 'baby biographies', hoping to find evidence supporting evolutionary theory. These records represent the first systematic studies in human development. Darwin's evolutionary theory has significantly influenced modern human development, including the concept of developmental stages. However, there has been criticism of 'baby biographies', with critics suggesting that studying children to validate a theory could lead to misinterpretation or omission of crucial information. **Development in the Real World** **Toys: More Than Just Playthings** Toys play a crucial role in children's development, serving as tools that aid their growth. Well-designed toys can enhance: - **Physical Development**: They improve muscle control, strength, and hand-eye coordination. - **Cognitive Development**: They bolster language and numeracy skills, and foster imagination and reasoning through creative expression and problem-solving. - **Emotional Development**: They provide a safe space for children to express their thoughts, feelings, and fantasies, and learn persistence and mastery. - **Social Development**: They teach children to share, cooperate, and practice social-cultural values and rules through pretend play. Therefore, the design of toys that promote these aspects of a child's development is of great importance. **The Developmental Science Behind Toys** In Canada, the design of toys considers whether they are age-appropriate, aligning with a child's abilities and interests. Toy-testing research focuses on factors such as safety, performance, appeal, usefulness, durability, age-appropriateness, and potential enhancements. As children progress through different developmental stages, they encounter new challenges and risks. Hence, the toy industries in Canada and internationally have established age-appropriate guidelines for toys to stimulate and challenge children based on their age, physical size, skill level, temperament, and maturity. Toys that do not match a child's capabilities could potentially hinder their interest development. Toy design and manufacturing involve extensive research, which is reflected in the information on toy product labels. These labels provide crucial guidelines for parents when choosing toys. For example, babies are at risk of choking on small toys or parts, toddlers may have accidents with riding toys due to undeveloped coordination, and projectile toys can cause injuries, particularly to the eyes. Consequently, toys are labeled with appropriate age ranges, such as "recommended for children from 18 months to 3 years." Safety warnings like "Choking hazard: This toy contains small parts and is not intended for children under the age of 3" are also common. Parental supervision is always essential, and toys intended for older children should be kept out of reach of younger ones. **Hall** G. Stanley Hall from Clark University sought more objective methods to study development, using questionnaires and interviews to research numerous children. His 1891 article, "The Contents of Children's Minds on Entering School," marked the first scientific study of child development. Hall concurred with Darwin that childhood milestones mirrored those in human species development. He proposed that developmentalists should establish norms, or average ages, for reaching developmental milestones. These norms could aid in understanding species evolution and tracking individual child development. **Gesell** Arnold Gesell\'s research proposed a genetically programmed sequence of change, termed as \'maturation\'. He believed that such maturation-driven development occurs irrespective of practice, training, or effort. For instance, infants naturally start walking at a certain age without being taught. Gesell, believing strongly in maturation as a determinant of developmental changes, spent years studying children and establishing norms. He innovatively used movie cameras and one-way observation devices for studying children\'s behavior. His findings form the basis of many norm-referenced tests used today to compare an individual child\'s development rate with that of their peers. These tests assist early educators in supporting young children whose development significantly deviates from their peers. **Piaget** Jean Piaget, a Swiss developmentalist, is renowned for his influential theories in human development. He began his scientific journey at the age of 10 and by 21, he had published over 20 scientific articles and earned a Ph.D. in natural science. In 1918, he collaborated with Theodore Simon, co-author of the Binet-Simon IQ test, in Paris. After marrying Valentine Châtenay in 1923, they documented the intellectual and language development of their children. Piaget, a professor at the University of Geneva from 1921, dedicated six decades to studying children\'s logical thinking development. He proposed that this development occurs in four stages from birth to adolescence. Initially, infants explore the world using their senses and motor skills, developing basic concepts of time and space. Young children then learn to use symbols, mainly words, for thinking and communication. Around the age of 6 or 7, they start developing logical thinking skills, which they use to solve everyday problems for the next five to six years. In their teenage years, they gain the ability to apply logic to abstract and hypothetical problems. Piaget\'s stages and his theory explaining them form the cornerstone of modern cognitive-developmental psychology. **A Brief History of the Roots of Developmental Psychology in Canada** The first psychology course in Canada was introduced at Dalhousie University in 1838, followed by prescientific psychology courses at McGill University and the University of Toronto in the 1850s. Initially, psychology was seen as a branch of mental and moral philosophy. Modern scientific psychology arrived in Canada in 1889. James M. Baldwin started lecturing at the University of Toronto and established a small psychophysical laboratory. In the 1920s, with the availability of funding for child-related and family research, William Blatz opened the St. George's School for Child Study in Toronto in 1925. Blatz, considered the pioneer of child study in Canada, also worked with the Dionne quintuplets for three years starting in 1935. The St. George's School was later renamed the Institute of Child Study and is now part of the Ontario Institute for Studies in Education (OISE). Before World War II, Canada had no formal organization for practicing psychologists. The looming threat of war in Europe in 1938 spurred psychologists to consider how they could contribute to the war effort. This led to the establishment of the Canadian Psychological Association (CPA) in 1939 by E.A. Bott, George Humphrey, and Roy Liddy from various Canadian universities. Mary Wright and Mary Salter (later Ainsworth) were also part of these initial discussions. Wright, an associate of Ainsworth, became the first woman president of the CPA in 1969. Ainsworth, known for her work on infant attachment, laid the foundation for understanding infant-caregiver relationships in developmental psychology. During World War II, Canadian psychologists were notably active, particularly in Britain. They concentrated on personnel selection, recruitment, training methods, morale issues, and public opinion. The major evacuation of children from urban centres in Britain led to significant advancements in early education, with Canadian psychologists devising solutions for child-care problems. William Blatz established a nursery school teachers' training school in Birmingham, staffed by Canadian child psychologists. In 1981, the Developmental Section of the CPA was founded to enhance communication among developmental psychologists regarding research, teaching, and practice. Currently, it serves as a collaborative platform for hundreds of members, sharing expertise. The Elinor Ames Award was recently introduced for the best student presentation in the Developmental Section at the annual CPA convention. **Contemporary Human Development** The field of human development has evolved significantly over time. It now covers the entire human lifespan, not just childhood and adolescence. There's a deeper understanding of how innate traits interact with environmental factors in intricate ways. While early pioneers primarily viewed change in terms of norms, modern developmentalists see norms as just one of many ways to gauge change. **The Lifespan Perspective** The perception of adulthood has evolved from being seen as a long stable period followed by a brief unstable phase before death. This change is due to the prevalence of major life changes in adulthood, such as divorce and career transitions. Additionally, life expectancy has significantly increased in developed countries. For instance, a Canadian male born today can expect to live beyond 80, and a female past 84, compared to 59 and 61 years respectively for those born in 1921. Consequently, the proportion of older adults in the population has grown, with those over 100 being one of the fastest-growing age groups in Canada, expected to increase fivefold to 40,000 by mid-century. The shifts discussed have resulted in the adoption of a lifespan perspective, which posits that significant changes occur at all stages of development and must be understood within their cultural and contextual framework. Consequently, understanding changes in adulthood is now considered as crucial as understanding those in childhood. A multidisciplinary approach is necessary for a comprehensive understanding of human development. Paul Baltes, an early pioneer in developing a comprehensive theory of lifespan human development, proposed that the potential for positive change, or plasticity, in response to environmental demands exists throughout life. He noted that older adults often pursue their goals more intensely than younger ones. Baltes emphasized the positive aspects of aging, suggesting that as people age, they adopt strategies to maximize gains and compensate for losses. An example he often cited was concert pianist Arthur Rubinstein, who outperformed much younger musicians into his 80s by strategically choosing well-known pieces (maximizing gain) and practicing them more frequently (compensating for age-related physical losses). **The Domains of Development** Scientists studying age-related changes typically categorize these changes into three broad domains of development. The physical domain encompasses changes in body size, shape, and characteristics. This includes studying physiological processes like puberty, and changes in sensory perception, such as the gradual development of depth perception during the first year of life. The cognitive domain encompasses changes in thinking, memory, problem-solving, and other intellectual abilities. Researchers in this field study a wide range of topics, from how children learn to read to the reasons behind memory decline in old age. They also investigate how individual differences, such as intelligence test scores, correlate with other factors within this domain. The social domain involves changes related to an individual's relationships with others. This includes studies on children's social skills, research on personality differences, and individuals' self-perceptions. Domain classifications aid in structuring discussions on human development, but it's crucial to remember that these domains are interconnected. For example, a girl undergoing puberty experiences changes in the physical domain, which also influence her abstract thinking (cognitive domain) and feelings about potential romantic partners (social domain). Similarly, older adults with Alzheimer's disease show evident changes in the cognitive domain, which are both a result of and lead to changes in the other two domains. Physical brain changes likely cause Alzheimer's disease, and living with the disease can disrupt regular eating and exercise habits, leading to physical health decline. Severe memory impairments can cause individuals to forget important details about their acquaintances, disrupting or even preventing social relationships. **Continuity and Discontinuity in Development** The continuity-discontinuity issue is a key topic in human development studies. It questions whether age-related changes are primarily quantitative (continuity) or qualitative (discontinuity). For instance, while the number of friends generally decreases from childhood to adulthood, the nature of friendship itself also changes. Characteristics like mutual trust become important in friendships as individuals grow older. Therefore, while the presence of peer relationships is a continuous aspect across all ages, the characteristics defining these relationships, such as mutual trust, vary with age, representing the discontinuous aspect. The continuity-discontinuity question in human development can be viewed in terms of quantitative and qualitative changes. Quantitative change, a continuous process, involves a change in amount, like children growing taller with age. On the other hand, qualitative change involves a change in characteristic or type, representing discontinuity. An example is puberty, a qualitative change where humans gain the ability to reproduce, a characteristic absent before puberty. Thus, prepubescent and postpubescent humans are qualitatively different. Another qualitative change occurs later in life when women undergo menopause and lose their reproductive ability. The study of human development considers whether development is a continuous, quantitative process of additions or a discontinuous, qualitative process involving reorganization and the emergence of new strategies, qualities, or skills. If development is continuous, the concept of stages, or distinct periods of development, may not be necessary. However, if development is discontinuous, the concept of stages could be useful. Theories of development differ primarily on whether they view development as stage-based or continuous. Despite these differences, most theorists and researchers agree that age-related changes can be categorized into three types: universal changes, group-specific changes, and individual differences. **Universal Changes** Universal changes refer to changes that occur in every individual of a species and are associated with specific ages. These changes can be due to our biological nature and the genetically programmed maturation process. For instance, an infant transitioning from crawling to walking or an older adult experiencing skin wrinkles are following a genetically determined plan. Some universal changes, however, are due to shared experiences. A 'social clock', which varies by culture, shapes lives into common patterns of change. This social clock, or set of age norms, outlines the sequence of typical life experiences, such as the right age to start school, the appropriate time for marriage and childbearing, and the expected retirement age. Age norms in society can foster ageism, a form of prejudice against older adults like sexism or racism. In Canada, there's a common belief that job performance decreases with age. This leads to older adults often being overlooked for work opportunities due to the assumption that they're less competent than their younger counterparts. Social expectations about the suitable age for retirement, combined with ageism, influence individual life paths, typically leading to retirement or reduced work hours in later adulthood. **Group-Specific Changes** Group-specific changes are common to all members of a particular group, with culture being a significant group we all belong to. Culture, though lacking a universally accepted definition, essentially represents a system of meanings and customs. This includes values, attitudes, goals, laws, beliefs, moral guidelines, and physical artifacts like tools and dwellings. Culture not only influences individual development but also shapes our perceptions of what constitutes normal development. Research on retirement often focuses on why people retire and its impact on their health. However, these findings may not be applicable to older adults in developing nations, where work transitions occur gradually rather than ceasing completely for retirement. Therefore, retirement-related phenomena are not universal but are culturally specific developmental experiences. Historical forces also significantly contribute to variations in life experiences, affecting each generation differently. The term 'cohort' is used to describe a group of individuals born within a similar timeframe, sharing the same historical experiences at the same life stages. Consequently, different cohorts within the same culture may have vastly different life experiences. **Individual Differences** Individual differences arise from unique events, with conception being a prime example as each person's genetic combination is unique. These genetic differences result in physical characteristics like body type and hair color, and genetic disorders. Another category of individual differences includes traits influenced by both heredity and environment, such as intelligence and personality. Additionally, the timing of developmental events can lead to individual differences. The concept of a 'critical period' suggests that there are specific stages in development when an organism is particularly sensitive to certain experiences. Much of our understanding of critical periods is derived from animal studies. For instance, the first 15 hours after hatching is a critical period for ducklings to develop a following response. During this time, they will follow any moving object around them. If no movement is present during this critical period, they do not develop a following response. In human development studies, the concept of a 'sensitive period' is widely used. This is a specific duration, spanning months or years, during which a child may be especially responsive to certain experiences or significantly affected by their absence. For instance, the age range of 6 to 12 months could be a sensitive period for developing parent-infant attachment. The presence or lack of specific environmental factors during these critical and sensitive periods can lead to lifelong changes, both positive and negative. This concept plays a crucial role in understanding epigenetics, which will be explored in more detail in subsequent chapters. In adult studies, the concept of 'on-time' and 'off-time' events is significant. 'On-time' events, which occur at culturally or cohort-expected times, are likely to cause less difficulty than 'off-time' events. For example, experiencing widowhood at 30 (an 'off-time' event) is more likely to cause severe life disruption or issues like depression compared to experiencing widowhood at 70 (an 'on-time' event). Atypical development represents a form of individual change that deviates from the 'normal' developmental pathway. This can include exceptionalities, developmental delays, psychological disorders, and behavioral issues. Examples of such behavioral problems could be extreme aggressiveness in children or compulsive gambling in adults. **The Interactionist Model of Development** Early developmentalists considered change because of either external or internal forces, leading to the nature-nurture debate about the influence of biological processes versus experiential factors. Over time, this binary view has evolved into a more nuanced understanding that considers both types of influences. Presently, many theorists adopt an interactionist model, viewing development as the outcome of complex reciprocal interactions between various personal and environmental factors. The interactionist model is exemplified in research on vulnerability and resilience. Each child is born with specific vulnerabilities, like emotional irritability, predisposition to alcoholism, physical abnormalities, or allergies. Simultaneously, each child also possesses protective factors such as high intelligence, good physical coordination, easy temperament, or a charming smile, which enhance their resilience against stress. These vulnerabilities and protective factors interact with the child's environment, leading to varied effects from the same environment, depending on the child's unique qualities. Research on Canadian children indicates that the most detrimental outcomes are observed when a highly vulnerable child is placed in a disadvantaged or unsupportive environment. However, if only one of these negative conditions is present---either a vulnerable child or an adverse environment---it can be mitigated. A resilient child can thrive even in a poor environment by leveraging available opportunities and stimuli. Similarly, a vulnerable child can succeed in a supportive environment where parents or caregivers help the child manage and overcome their vulnerabilities. **Research Methods and Designs** **Relating Goals to Methods** Developmental researchers use the scientific method to achieve four goals: to describe, explain, predict, and influence human development from conception to death. **Describe** Describing development involves stating observable changes. For instance, in human development, a descriptive statement might be "Older adults make more memory errors than young and middle-aged adults." The validity of this statement can be tested by measuring memory function across different age groups. **Explain** Explaining development is about understanding the reasons behind certain events. Developmentalists use theories, which are sets of statements proposing general developmental principles, to create these explanations. Despite some students preferring facts over theories, theories are crucial as they offer different perspectives on facts. For instance, the statement "Older adults make more memory mistakes due to age-related brain changes" explains age-related memory decline from a biological viewpoint. Alternatively, this memory decline could be explained from an experiential perspective, hypothesizing that it occurs because older adults don't practice memory as much as younger adults. **Predict** Effective theories generate testable predictions or hypotheses. For instance, if brain changes cause memory function decline, then older adults with the most brain changes should have the most memory errors. To test this, we'd need to measure aspects of brain structure or function and memory function, and then establish a relationship between them. Alternatively, the experiential explanation could be tested by comparing the memory of older adults who get the most memory practice, like those still working, with those who get less practice. If working adults perform better on memory tests, it supports the experiential perspective. Thus, theories significantly enhance researchers' understanding of human development facts and provide valuable information to influence development. **Influence** If an older adult is diagnosed with a condition like high blood pressure that can impact the brain, understanding the relationship between brain function and memory can be useful. Memory tests can help assess the extent to which the medical condition has affected the person's brain. Additionally, knowing that experience also influences memory, we could potentially offer training to help prevent or mitigate the development of memory issues. **Research Methods for Identifying Relationships Between Variables** A researcher studying the relationship between age and memory must determine how to identify relationships between variables. In developmental studies, variables are characteristics that differ among individuals, like physical size, intelligence, and personality. When two or more variables co-vary, it indicates a relationship. The hypothesis that memory declines with age involves two variables---memory and age---and suggests a relationship between them. There are multiple methods to identify such relationships. **Descriptive Methods** Case studies are comprehensive investigations of individual subjects. To examine the hypothesis about memory and age, a case study could compare an individual's memory test scores from early to late adulthood. This could provide valuable insights into the stability or instability of memory in the studied individual, but it wouldn't indicate if the findings are generalizable. Despite their limitations, case studies are highly beneficial in making individual assessments. For instance, to determine if a child has intellectual delays, a psychologist would conduct a thorough case study involving tests, parent interviews, and behavioral observations. Case studies often form the basis for significant hypotheses about atypical developmental events, such as head injuries and strokes. Naturalistic observation is a research method where psychologists observe individuals in their usual environments, such as observing older adults in their homes or workplaces to study memory. This method provides insights into psychological processes in real-world contexts. However, naturalistic observation has its limitations, notably observer bias. If a researcher, for instance, firmly believes that most older adults have poor memory, they might overlook behaviors that contradict this belief. To mitigate observer bias, studies often employ 'blind' observers unaware of the research's purpose. Typically, multiple observers are used to cross-verify observations for accuracy. Like case studies, naturalistic observation studies have limitations in terms of generalizability. They are also time-consuming and need to be conducted in various settings to ensure the observed behavior reflects development and not just environmental influences. Surveys, on the other hand, are studies where researchers use interviews or questionnaires to gather data about attitudes, interests, values, and behaviors. If you've ever been asked about health practices, voting preferences, etc., you've participated in a survey. Surveys are efficient tools for quickly collecting information and can track changes over time. **Correlations** A correlation represents a relationship between two variables, expressed as a number between -1.00 and +1.00. A zero correlation signifies no relationship between the variables. A positive correlation indicates that high scores on one variable typically correspond with high scores on the other, with the relationship strength increasing as the correlation approaches +1.00. A negative correlation, nearing -1.00, signifies a strong inverse relationship where the variables change in opposite directions. Positive and negative correlations can be understood through the relationship between temperature and the use of air conditioners and heaters in Canada. There is a positive correlation between temperature and air conditioner use, meaning as temperature rises, the use of air conditioners increases. On the other hand, there is a negative correlation between temperature and heater use, implying that as temperature drops, the use of heaters increases. To determine if age is related to memory, a correlational study could be conducted. This would involve administering memory tests to adults of different ages and calculating the correlation between test scores and ages. If a positive correlation is found, indicating that older people make more errors, it would support the hypothesis. However, if a negative correlation is observed, meaning older people make fewer errors, it would suggest that the hypothesis is not supported. While correlations are valuable, they have a significant limitation: they do not establish causal relationships. For instance, a high positive correlation between memory errors and age only indicates a connection between the two, not what causes this connection. It could be that younger adults comprehend test instructions better. To identify a cause, experiments must be conducted. **Experiments** An experiment is a study designed to test a causal hypothesis. For instance, if we hypothesize that memory differences in older adults are due to their lack of memory techniques, such as mentally repeating a list for memorization, we could test this. We would provide memory technique training to one group of older adults and no training to another group. If the trained group shows improved memory test scores post-training, while the untrained group shows no change, it would support our hypothesis. A crucial aspect of an experiment is the random assignment of participants to two or more groups. This means that group placement is determined by chance. With random assignment, the groups have equal variations in characteristics like intelligence, personality traits, height, weight, health status, etc. As a result, these variables cannot influence the experiment's outcome. In an experiment, participants in the experimental group receive a treatment that is hypothesized to have a specific effect, while those in the control group receive no special treatment or a neutral one. The factor presumed to cause an effect in the experiment is the independent variable, and the characteristic or behavior it's expected to influence is the dependent variable. In the suggested memory technique training experiment, the experimental group is the one that receives the memory training, while the control group receives no instruction. The independent variable is the memory technique training, which is hypothesized to cause differences in memory function. The dependent variable is the performance on memory tests, which is used to measure the effect of the memory technique training. Experiments are crucial for understanding various aspects of development. However, there are limitations in studying child or adult development. Many research questions involve the effects of stressful or unpleasant experiences on individuals---such as abuse, prenatal alcohol or tobacco exposure, low birth weight, poverty, unemployment, widowhood. Ethical considerations prevent researchers from manipulating these variables---for instance, they can't instruct a group of pregnant women to consume alcohol daily. To study the effects of such experiences, researchers must rely on non-experimental methods, like correlations. A significant independent variable of interest for developmentalists is age, but researchers cannot randomly assign participants to different age groups. While comparisons can be made between different age groups, such as 4-year-olds and 6-year-olds, on specific tasks, these children differ in numerous ways beyond their ages. Older children have more varied experiences. Therefore, unlike psychologists studying other behavioral aspects, developmental psychologists cannot systematically manipulate many of the variables they are most interested in. To circumvent the problem of not being able to randomly assign participants to age groups, researchers can use strategies known as quasi-experiments. These involve comparing groups without random assignment. Cross-sectional studies and studies comparing naturally occurring groups differing in certain aspects, like children in daycare versus those kept at home, are examples of quasi-experiments. However, these comparisons have inherent issues as groups differing in one aspect are likely to differ in others too. For instance, parents sending their children to private schools might be wealthier and have different social values compared to those who opt for public schools. If differences are found in the academic measures of these two groups of children, it's challenging to determine if it's due to their different schooling environments or other family differences. Researchers can somewhat alleviate this issue by selecting comparison groups matched on variables they believe might be significant, like income, marital status, or religion. However, by its nature, a quasi-experiment will always yield more ambiguous results than a fully controlled experiment. **Research Designs for Studying Age-Related Changes** When researching age-related changes, a researcher essentially has three options: 1. Use a **cross-sectional design** to study different age groups of people. 2. Use a **longitudinal design** to study the same group of people over a period of time. 3. Use a **sequential design** to combine aspects of both cross-sectional and longitudinal designs. **Cross-Sectional Designs** Figure 1.1 illustrates a cross-sectional study where researchers investigated the ability of different age groups to recognize anger in facial expressions. The study found that younger adults were better at identifying anger than older adults. While these results might suggest that the ability to recognize anger declines with age, the study's cross-sectional nature means we cannot make this conclusion definitively. This is because the adults in the study differ in both age and cohort, meaning differences such as education levels could be influencing the results, not just age or development. These influences can lead to cohort effects, which are findings influenced by historical factors specific to certain age groups in a cross-sectional study. Cross-sectional studies, while useful and time-efficient, have limitations. They can't provide information about changes over time or the consistency of individual behavior, as each participant is tested only once. However, they are valuable in identifying potential age differences or changes. **Longitudinal Designs** Longitudinal designs appear to address the limitations of cross-sectional studies by tracking the same individuals over time. These studies enable researchers to observe patterns of change and assess the consistency or inconsistency of individual behavior over time. As longitudinal studies compare the performance of the same individuals at different ages, they can mitigate some of the cohort-related issues inherent in cross-sectional studies. Several renowned Canadian longitudinal studies have been tracking groups of children into adulthood. One such study is the Concordia Longitudinal Risk Project (CLRP), initiated in 1976 by Alex Schwartzman and Jane Ledingham. The CLRP initially focused on children from low-income, inner-city neighborhoods, who are now in their 50s and still part of the study, along with their children. More recent studies are conducted by the Research Unit on Children's Psychosocial Maladjustment (GRIP), a multidisciplinary, inter-university group of researchers. This group oversees several projects, including the Quebec Study of Newborn Twins (QSNT), the Quebec Longitudinal Study of Kindergarten Children (QLSKC), and the Quebec Longitudinal Study of Child Development (QLSCD). These projects play a crucial role in understanding human development. Longitudinal studies, despite their importance, have several limitations. They are time-consuming and maintaining contact with subjects over extended periods can be challenging. Participant attrition due to dropouts, death, or relocation is common. Repetitive testing can lead to practice effects, potentially distorting the measurement of developmental changes. Typically, the healthiest and best-educated participants are most likely to remain in the study, introducing bias, especially in studies spanning the later decades of life. This can create an illusion of less change or decline than exists, as test results increasingly represent a healthier subset of adults. Furthermore, longitudinal studies don't fully resolve the cohort issue. Studies conducted in the past may be influenced by unique factors pertaining to that specific group or time. Each generation's experiences are shaped by distinct cultural, social, economic, and historical conditions, which may not be applicable to individuals from different eras. **Sequential Designs** A sequential design is a method that can overcome the limitations of both cross-sectional and longitudinal designs. In this approach, at least two age groups are studied, for example, 25- to 30-year-olds and 30- to 35-year-olds. Each group is tested multiple times over several years. This design allows for two types of comparisons at each testing point beyond the first. Age-group comparisons yield information like a cross-sectional study, while comparing each group to its earlier performance provides longitudinal data. Thus, a sequential design effectively combines the strengths of both cross-sectional and longitudinal studies. Sequential designs facilitate cohort comparisons. For instance, in Figure 1.3, Group A (30-35 years old at testing point 1) and Group B (30-35 years old at testing point 2) can be compared. Similarly, comparisons can be made when Group A is 35-40 at point 2 and Group B is of the same age at point 3. If these same-age groups show different memory performances, it indicates cohort differences. If their performances are similar, it suggests that the observed characteristics are developmental, not cohort effects. If both groups show similar age-related changes over time, it implies that the developmental pattern isn't cohort specific. Thus, finding the same developmental pattern in two cohorts gives stronger evidence than cross-sectional or longitudinal data alone. In 1994, Human Resources Development Canada initiated an extensive sequential design study called the National Longitudinal Survey of Children and Youth (NLSCY). The NLSCY aimed to understand how social and environmental factors impact a child's development across various domains. The study began with nearly 23,000 children aged 0 to 11 years and collected data every two years until the youngest participants reached 25 in 2018. Each two-year cycle added a new sample of newborns and 1-year-olds. Between 1994 and 2010, the NLSCY surveyed almost 36,000 Canadians from birth to 25 years of age. **Cross-Cultural Research** In human development research, studies comparing cultures or contexts are becoming more prevalent. One approach is through ethnography, which provides a detailed description of a single culture or context based on extensive observation. This often involves the observer living within the culture or context for an extended period, sometimes several years. Each ethnographic study is designed to be independent, but there can be instances where data from multiple studies are combined to identify if similar developmental patterns exist across different cultures or contexts. Researchers may also directly compare two or more cultures by using the same or similar measures to test individuals from each culture. This can involve comparing groups from different countries or subcultures within the same country. For instance, in Canada, it's increasingly common to compare children or adults from different ethnic groups or communities, such as First Nations, South Asian, Caribbean, or European Canadians. This research is significant in Canada, which was the first country to officially adopt multiculturalism as a policy in 1971, with the Canadian Multicultural Act passed in 1988. Cross-cultural research is crucial to developmental psychology for two main reasons: - **Identifying Universal Changes**: Developmentalists aim to pinpoint predictable events or processes that individuals in all cultures experience. They avoid making general statements about development, such as "Memory declines with age," if it only occurs in specific cultures. Without cross-cultural research, it's impossible to determine if studies involving North Americans and Europeans are applicable globally. - **Improving Lives**: Another goal of developmentalists is to generate findings that can enhance people's lives. Cross-cultural research is vital to this aim. For instance, it's known that children in cultures that prioritize community over the individual are more cooperative than those in more individualistic cultures. To use this knowledge to help all children learn cooperation, researchers need to understand how adults in these cultures teach cooperation. Cross-cultural research aids in identifying specific variables that account for cultural differences. **Research Ethics** The CPA (2000, 2017) has published ethical standards for practitioners, researchers, and scientists that include the following principles: respect for the dignity of persons and peoples, responsible caring, integrity in relationships, and responsibility to society. These ethical standards are used in a deliberate and balanced manner to address the following major concerns. **Protection from Harm** Research ethics dictate that it is unethical to conduct research that could cause participants permanent physical or psychological harm. If there's a risk of temporary harm, researchers are obligated to offer a means of rectification. For instance, if a study could trigger reminders of distressing experiences like sexual assault, researchers must provide counselling to the participants. **Informed Consent** Researchers are required to clearly inform participants about any potential harm and obtain their signed consent, acknowledging their understanding of the risks involved. For children to participate, parental consent is needed after parents are informed of potential risks. Children over 7 must also give their assent. If the research is conducted in a school or daycare, an institutional representative must give consent. Both children and adults have the right to withdraw from the study at any time, and researchers must explain this right to children in an understandable manner. **Confidentiality** Participants in research studies have a right to confidentiality. Researchers are obligated to maintain participant anonymity and present data in a manner that prevents the association of specific information with individual participants. However, an exception to this confidentiality exists when children disclose any form of abuse by an adult to researchers. In such cases, Canadian law mandates the reporting of suspected child abuse. **Knowledge of Results** Participants, their parents, and the administrators of institutions in which research takes place have a right to a written summary of a study's results. **Deception** In certain instances, deception may be required in research studies to prevent participant expectations from influencing behavior and biasing results. However, if deception is used, it must not cause distress to participants, and they have the right to be informed about the deception immediately after the study concludes. **List of Key Terms** **Ageism:** a prejudicial view of older adults that characterizes them in negative ways. **atypical development:** development that deviates from the typical developmental pathway. **case study**: an in-depth examination of a single individual **cognitive domain:** changes in thinking, memory, problem-solving, and other intellectual skills. **Cohort**: a group of individuals who share the same historical experiences at the same times in their lives. **control group**: the group in an experiment that receives either no special treatment or a neutral treatment. **Correlation**: a relationship between two variables that can be expressed as a number ranging from -1.00 to +1.00. **critical period**: a specific period in development when an organism is especially sensitive to the presence (or absence) of some particular kind of experience. **cross-sectional design**: a research design in which groups of different ages are compared. **dependent variable**: the characteristic or behaviour that is expected to be affected by the independent variable. **Ethnography:** a detailed description of a single culture or context. **Experiment**: a study that tests a causal hypothesis. **experimental group**: the group in an experiment that receives the treatment the experimenter thinks will produce a particular effect. **human development**: the scientific study of age-related changes in our bodies, behaviour, thinking, emotions, social relationships, and personalities. **independent variable**: the presumed causal element in an experiment. **interactionist model**: the theory that development results from complex reciprocal interactions between multiple personal and environmental factors. **lifespan perspective**: the current view of developmentalists that changes happen throughout the entire human lifespan and that changes must be interpreted considering the culture and context in which they occur; thus, Interdisciplinary research is critical to understanding human development. **longitudinal design**: a research design in which people in a single group are studied at different times in their lives. **Maturation**: the gradual unfolding of a genetically programmed sequential pattern of change. **naturalistic observation**: the process of studying people in their normal environments. **norms**: average ages at which developmental milestones are reached. **norm-referenced tests**: standardized tests that compare an individual's score to the average score of same-aged peers. **physical domain**: changes in the size, shape, and characteristics of the body. **Plasticity**: the ability of the brain to change in response to experience. **qualitative change**: a change in characteristic, kind, or type. **quantitative change**: a change in amount. **research ethics**: the guidelines that researchers follow to protect the rights of animals used in research and humans who participate in studies. **sensitive period**: a span of months or years during which a child may be particularly responsive to specific forms of experience or particularly influenced by their absence. **sequential design**: a research design that combines cross-sectional and longitudinal examinations of development. **social clock**: a set of age norms that defines a sequence of life experiences that is considered normal in a given culture and that all individuals in that culture are expected to follow. **Stages**: qualitatively distinct periods of development **Survey**: a data collection method in which participants respond to questions