PSY 2105 Developmental Psychology PDF

Chapter 1 - Background and Theories 1.1 - WHAT IS DEVELOPMENTAL PSYCHOLOGY ? Developmental psychology is the study of human behavior. More specifically, it observes the changes in behavior and abilities that occur throughout the development and identifies their causes. The two basic goals in this...

Chapter 1 - Background and Theories 1.1 - WHAT IS DEVELOPMENTAL PSYCHOLOGY ? Developmental psychology is the study of human behavior. More specifically, it observes the changes in behavior and abilities that occur throughout the development and identifies their causes. The two basic goals in this type of research are : Description - Identify children’s behavior at each point of their development. Explanation - Determine the causes and processes that produce changes in behavior. 1.2 - WHY STUDY CHILDREN ? a) Period of Rapid Development Researchers are interested in studying change, thus the reason why they would pick the period of life where the most development takes place : childhood. Involves psychical growth, social interactions, acquisition of language, memory abilities, etc. b) Long-term Influences Events and experiences of the early years strongly affect an individual’s later development. c) Insight into Complexe Adult Processes Researchers found it easier to understand complex adult behaviors during a period when they are not so complex. d) Real-World Applications The findings of this type of research benefits children with real-world problems (ex. poverty, drugs and crimes). e) Interesting Subject Matter This field reflects an individual's love of children and interest in their behavior and development. 1.3 - HISTORICAL VIEWS OF CHILDHOOD Ancient Greece and Rome (600 B.C - 400 B.C) Plato and Aristotle wrote about the importance of education, but defended practices that today would seem unthinkable. Infanticide : The killing of newborns to deal with babies who were illegitimate, unhealthy or simply unwanted. Severe punishment and exploitation of children were not uncommon or considered wrong ➔ For example, selling children for various purposes - sexual pleasure, domestic work, etc The Medieval and Renaissance Periods (14th century - 17 century) Unlike Plato and Aristotle, the Catholic church was promoting children as pure and innocent ; were against infanticide, instead sent unwanted children to convents and monasteries. Abuse and exploitation of children was still common in this period of time. 1.4 - EARLY THEORISTS John Locke (1632 to 1704) - Environmentalist physician He believed all children were born equal and that the mind of a newborn is like a Tabula Rasa (“blank slate”). It is only through experiences and learning that knowledge comes to the child. Thus meaning that any child is theoretically capable of becoming anything ; they are simply products of their environment and upbringing. He believed in the use of rewards (praise) and punishments (scolding) to shape behavior. He stresses the importance of stimulation for children at a very young age. Jean-Jacques Rousseau (1712 to 1778) - Nativism philosopher Nativism : The theory that human development results from inborn processes that guide the emergence of behaviors in a predictable manner. He believed that children are born with knowledge and ideas that unfold with age and that development follows a series of stages guided by a timetable. He believed that whatever knowledge the child does not possess at birth, it can be acquired through interactions with its environment. (Must be learnt through exploration and discovery, not by instructions) Johann Gottfried Von Herder (1744 to 1803) He believed that everyone is born into a specific cultural community with a shared language and historical traditions ; these practices shape the minds of members in the community. Against the attempts to impose one culture’s values on another. Cultural relativism : The idea that each culture must be examined and evaluated on its own terms. He puts emphasis on the language and dynamic nature. Charles Darwin (1809 to 1882) - Biologist He believed that individual members of a species vary in many different characteristics from each other. ➔ The cause of that variation is biological ; from inborn, hereditary differences that can be passed on from parents to the children. He assumed that most species produce more offspring than their environment can support, which creates competition for survival (known as the concept of natural selection). Natural selection : Species evolve to more adaptive forms to survive in their environment. His theory led to the principle of recapitulation in which the development of the individual proceeds through stages that parallel the development of the entire species. Baby biography method : The study of one’s own child’s development. ➔ Darwin was one of the first development studies when he recorded the growth and behavior of his son Doddy. 1.5 - PIONEERS OF CHILD PSYCHOLOGY G. Stanley Hall (1846 to 1924) - Father of child psychology He conducted and published the first systematic studies of children in North America. His contribution to the field ultimately led to the introduction of the psychoanalytic theory. James Mark Baldwin (1861 to 1934) He argued that development progresses through a sequence of stages and stressed the interaction between heredity and the environment. These notions influenced Jean Piaget’s theory about development. John B. Watson (1878 to 1958) Zeitgeist : German term that means “the spirit of the times” = dramatic change in the way we think. He was the first major psychologist to adopt Locke’s belief that human behavior is thought through experiences and learning. And rejected the method of introspection which involved engaging participants in tasks and reporting the process occurring in their mind when completing them. He developed his own psychological approach : behaviorism. Arnold Gesell (1880 to 1961) - G. Stanley Hall’s most successful student He believed that development is guided primarily by biological processes (maturation). ➔ The environment plays a minor role ; could affect at which age the skill is acquired, but never the sequence of patterns during the development. He established statistical norms (developmental timetable that describes the usual order in which children display various behaviors and the age range in which they normally appear). **Still used today** He adapted the use of film cameras to record children’s behaviors and one-way viewing screens around a dome to not disturb the child while it is being studied. Sigmund Freud (1856 to 1939) He made two major contributions to the field of psychology : 1. In clinical psychology, he created the model of personality and techniques of psychoanalysis. 2. In developmental psychology, he created the stages theory of psychosexual development. His theory explains that each child is born with a certain amount of sexual energy (libido), which is biologically guided to certain body parts (erogenous zones). ➔ If the child receives the proper amount of physical pleasure from that erogenous zone, it can successfully move onto the next stage. ➔ If a stage is not succeeded, some portion of the libido remains fixated on that erogenous zone. ➔ The most complex stage is the phallic stage (concept of oedipus and electra). The child will go through two stages : 1. Repression : Child will force their desire into the unconscious (wipes memory of the feelings). 2. Identification : Child will compensate by adopting the same characteristics as the viral parent. He is one of the first to argue for an interactionist perspective : The belief that both inborn processes and environmental factors are contributors to the child’s development. He suggested that early experiences can have an impact on later life. Erik Erikson (1902 to 1994) He believed that we couldn’t understand the development of personality without considering the environment. He based his model from Freud’s, but believed the development continues throughout life.  Each child is guided through the stages by genetic processes, but social and cultural surroundings can help determine how the individual will resolve the conflict. 1.6 - ISSUES IN DEVELOPMENTAL PSYCHOLOGY a) Nature versus Nurture Nature : Biological factors Nurture : Environmental or experiential factors Watson’s theory takes on the nurture perspective — Hall and Gesell’s theories are based on the nature position. Most psychologists emphasize the importance of nature versus nurture in their theories on development. Exemple. Some psychologists explain aggressive behaviors by environmental factors (exposure to violent models or ineffective parenting) that rewards aggressions. Others blame biological accounts (inherited disposition or neurological problems) that make it difficult for the child to regulate its emotions Concept best understood when combining both the biological and environmental factors. b) Continuity versus Discontinuity Continuous : The pattern of development is smooth and stable. Look for quantitative change. Discontinuous : The pattern of development occurring at different rates. Look for qualitative change. c) Normative versus Idiographic Development Normative development : It focuses on the “average” child to identify and describe the normal development. The universal development observes behaviors/patterns of development that characterize all children. Theorists look for common patterns + associated with biological theories. Idiographic development : It centers on one child and the factors that produce human diversity. Theorists look for different patterns + associated with environmental factors. 1.7 - THEORIES OF DEVELOPMENT Cognitive-Developmental Approaches Jean Piaget’s theory Piaget is more interested in the reason why the kids got the wrong answer instead of the right answer. His area of interest was genetic epistemology : The study of the nature of knowledge in young children, its origin and how it changes as they grow older. His method of testing involved giving children simple tasks and verbal problems that require solutions and explanations = clinical method. In his theory, human development can be described in terms of functions and cognitive structures. Cognitive structures Schemes : They are patterns of thought or behavior that organize categories of information and the relationships among them. They involve two elements : objects in the environment and the child’s reaction to said object. ➔ Infants don’t have a lot, but as development proceeds, schemes increase in both numbers and complexity. Cognitive structures are flexible and can change overtime. This can be explained as schemes eventually become more individualized and differentiated. Development : The continual reorganization of knowledge into new and more complex structures. Functions Functions guide the cognitive development, there are two general functions : 1. Organization : The cognitive structures are interrelated, any new knowledge must be fit into the existing systems which forces our cognitive structures to become more elaborated and organized. 2. Adaptation : The attempt to fit with its environment in ways to promote survival, which involves two processes. Assimilation : Tries to make sense of new experiences in terms of existing cognitive structures. Accommodation : When new information is too different or too complex our cognitive structures change in order to integrate the new experiences. Concept of constructivism : Piaget’s belief that children actively create knowledge, rather than passively receive it from the environment. ➔ Children shape and bend new cognitive structure into the pre-existing organization (construct knowledge about the world, rather than simply receiving it). Stages of development 1. Sensorimotors (0-2 years old) : The infants initial schemes are simple reflexes and their knowledge of the world is limited to physical interactions with people and objects. 2. Preoperational (2-6 years old) : The child begins to use symbols, such as words and numbers, to represent the world cognitively. 3. Concrete Operations (6-11 years old) : The child is able to perform mental operations on the pieces of knowledge they possess ; permitting a kind of logical problem solving that wasn't possible before. 4. Formal Operations (12-adult) : Includes all the higher level abstract operations and adding reasoning to their actions. Information-Processing Models This approach views cognition as a system composed of three parts : 1. The information in the world provides the input to the system ; the stimulation enters our senses in the form of sights, sounds, tastes, touch and smell. 2. The processes in the brain transform the information by encoding it into symbolic forms, comparing it with previously acquired information, storing it in the memory and retrieving it when necessary. 3. Behavior-speech, social interactions, writing form the output of the system. Researchers use the computer analogy : Information flowing through a system where it is processed and then re-emerges in a different form, just like a computer. Researchers are not simply interested about what changes occur with age, but also why they take place. Sociocultural Approaches The theorists believe development occurs in social, cultural and historical context. It includes cultural tools and traditions to shape mental processes. Lev Vigotsky’s theory His model shows that the individual’s development (thought, language and reasoning) is a product of its culture. He assumed the development of these abilities was through social interactions (especially parents). He believed intellectual abilities were more specific to the culture in which the child was raised. Claim that culture makes two contributions to the child’s development : 1. Children acquire much of the content of knowledge from the culture around them. 2. Children acquire their thinking and reasoning processes (tools of intellect) from their culture. He believed that cognitive development resulted from a dialectical process where a child learns through shared problem-solving experiences with someone else. Development as a process of internalization : Bodies of knowledge and thinking tools at first exist outside the child, in the surrounding culture. During the development, these bodies gradually internalize the child. At first, the adult assumes most of the responsibility of guiding the problem solving. And gradually, the responsibility shifts partly and then completely to the child. Urie Bronfenbrenner’s theory His ecological approach was based on the notion that to understand development, one must consider the unique characteristics of a child's interaction with its surroundings. The child possesses a variety of personal characteristics : Developmentally generative : Capable of influencing people in ways that are important to them. Developmentally disruptive : Capable of cousin problems in the environment with corresponding negative effects on them. By instigating various responses and reactions from others, the child becomes “producer” of its own environment. Positive personality traits : sociability, cooperativeness and curiosity  Negative personality traits : impulsiveness, explosiveness and distractibility His theory claims that the child and the environment continually influence each other (bidirectional manner). Bronfenbrenner proposed a theory on how genes and environment operate together to guide human development. Brofenbrenner’s ecological model : Microsystem : The environmental system closest to the child. Mesosystem : The interrelationships among the child’s microsystems. Exosystem : The social systems that can affect the child (do not participate directly). Macrosystem : The culture of subculture in which the child lives. Chronosystem : The passage of time for studying human development. a) Environmental/ Learning Approaches This theory believed that many human behaviors, especially social, are acquired rather than inborn. The theorists accept that biological and cognitive factors contribute to human development, but don’t agree that biology and evolutionary history dictate human development. They also do not agree that cognition is the fundamental process in psychological development and that changes in behavior always reflect or require advances in cognitive abilities. Learning : A relatively permanent change in behavior that results from practice or experience. “Relatively permanent” : Distinguishes learned changes in behavior that are only temporary and often reflect physiological processes (sleep, illness or fatigue). “Change in behavior” : Learning must always be demonstrated through changes in observable behavior. “Results from practice or experience” : To separate learned changes in behavior from changes caused by general biological processes (growth, pregnancy or death). B.F. Skinner’s theory According to his model, all behaviors fall into one of these categories : 1. Respondent behavior : Completely controlled by the stimulus that elicits it, the response occurs when the stimulus is present and doesn’t when the stimulus is absent. Reflexes : Composed of a stimulus and elicits a response (biological and inborn). Responses are more obvious during infancy (physical response) vs teenagers and adults (psychological and emotional responses). 2. Operant behavior : Voluntary responses controlled by their effects (consequence they produce). Pleasant consequences : Behaviors more likely to occur again. Unpleasant consequences : Behaviors less likely to occur again. Habituation : The decline or disappearance of a response as a result of repeated presentation of the eliciting stimulus. For example, a baby sleeps through noise in the house during its nap because it is used to it. Dishabituation : The recovery of habituated response that results from a change in the eliciting stimulus. For example, the repeated hand clapping has reduced the startle to a very low level. After waiting 15 seconds we sound a loud buzzer instead of clapping our hands. With great reliability, the startle response will repeat. Classical conditioning (respondent conditioning) - by Ivan Pavlov The stimulus starts off as an unconditioned stimulus (UCS). The UCS elicited an unconditioned response (UCR). The neutral stimulus is paired/ associated with the UCS. After a number of pairing, it elicits the UCR, to the point where the previously neutral stimulus is now a conditioned stimulus (CS). Classical conditioning often produces stimulus generalization where a stimulus similar to the conditioned stimulus (CS) also becomes conditioned. Extinction : A process in which the conditioned stimulus (CS) gradually loses its power to elicit the response as a result of no longer being paired with the unconditioned stimulus (UCS). **Famous research by John B. Watson involving conditioning is Little Albert and Little Peter : Conditioning. Operant learning The theorists believed operant behaviors are influenced by their effects and that that children's everyday behaviors occur simply because they resulted in desirable consequences in the past. Reinforcer : Any consequence that makes a response more likely to occur again. Positive reinforcer : Consequence that makes the behavior it follows more likely through the presentation of something pleasant. Negative reinforcer : Consequence that makes the behavior it follows more likely through the removal of something unpleasant. Reinforcement process works on appropriate, inappropriate or neutral responses. Punisher : Any consequence that makes a response less likely to occur again. Positive punisher : Consequence that makes the behavior it follows less likely through the presentation of something unpleasant. Negative punisher : Consequence that makes the behavior it follows less likely through the removal of something desirable. Social-learning theory A form of environmental/ learning theory that adds observational learning to classical and operant learning as a process through which children’s behaviors change. Observational learning theory A form of learning in which an observer’s behavior changes as a result of observing a model. In developmental psychology, children = observers and others around them = models. Three important questions studied by Albert Bandura and other researchers : 1. Which models are most likely to influence a child’s behavior ? Any model who possesses a characteristic that the child finds attractive or desirable (likely to imitate). Bandura claims the consequences of a model’s behavior can affect the behavior of the observer. When the observer see’s model get reinforcement for a response, the observer receives vicarious reinforcement. The opposite is true for when an observer receives vicarious punishment. Imitation : When the observer copies the models actions, words and thoughts. Response inhibition : When the observer is less likely to perform a behavior that has just been modeled. 2. Under what circumstance is the influence most likely to occur ? 3. How does a child’s behavior change as a result of observational learning ? Bandura’s Bobo Doll Experiment One group of kids observed a model rewarded for showing aggressive behavior towards the dolls. The other group saw that same behavior being punished.  When it came time for them to play with the doll themselves, the kids who observed the reinforcement imitated the model’s aggressive behavior towards the dolls. However, the group that observed the punishment did not. Later offered rewards for reproducing the aggressive behaviors, both groups were able to perform them quite accurately. Attentional processes determine how closely the child pays attention to the model’s actions. Retention processes refer to how well the child stores the modeled information in its memory. Production processes control how well the child can reproduce the model’s response. Motivational processes determine who and what a child chooses to imitate. Bandura’s theory suggests four reasons why children do not imitate everything. 1. Doesn’t pay attention to what the model was doing. 2. Doesn’t recall the model’s responses. 3. Doesn’t possess the physical skills to repeat the model’s behavior. 4. Doesn't feel motivated to do what the model did. Bandura’s analysis views human development as a reflection of the interactions of the person (p), the person’s behavior (b) and the environment (e). This interaction is called reciprocal determinism. Children choose what they want to do (P → B) and with whom to do it (P → E). Children’s behavior can affect their feelings, their attitudes and beliefs about things (B → P). Much of children's knowledge results from information they receive from TV, parents, textbooks and other environmental sources (E → P). Environment also affects behavior. The consequences of children’s behavior and the models they observe can powerfully influence what they do (E → B).  Children who stare and cooperate with classmates are likely to attract many friends, whereas the opposite may be the case for a child who behaves selfishly or aggressively (B → E). b) Evolutionary and Biological Approaches The modern version of this approach begins with the disciple of ethology : The study of development from an evolutionary perspective. According to ethologists, changes has two kinds of determinants : 1. Immediate : Changes more obvious and include the environment in which the behavior occurs. For example, the animal’s recent experiences, and the state or condition of the animal. 2. Evolutionary : Changes less obvious and selected behaviors or characteristics for evolution. Ethologists identified fours qualities that characterize all innate or inborn behaviors : 1. They are universal to all members of the species. 2. They are usually biologically programmed responses to specific stimuli (require no learning/ experience). 3. They are normally stereotyped, meaning they occur precisely in the same way every time. 4. They are minimally affected by environmental influences (natural selection pressure affects them). Model action patterns : A sequence of behaviors elicited by a specific stimulus in the environment. Innate releasing mechanism : A stimulus that triggers an innate sequence or pattern of behaviors. Ethologists argue that animals are biologically programmed (things learned easier in specific periods of develop.) For example, Lorenz’s research on imprinting, the process by which newborns of some species form an emotional bond with their mothers. ○ Lorenz guessed that the act of following was responsible for the strong social bond that developed between the newborn and the parent. ○ He discovered the most important influences on imprinting was the age of the chicks. If the act of following occurred during the period several hours after birth and lasted until sometime the next day, the attachment bond reliably developed. If the following occurred only before or after this period, little or no imprinting resulted. ○ Sensitive periods : Describes points in development when learning is much easier. John Bowlby’s theory His theory suggested that physical characteristics of babies (head shape or sound of cries) might serve as stimuli to trigger caregiving by mothers. Bowlby believed that the quality of the early relationship is critical to later development, and these first experiences are carried forward by processes in the unconscious (like Freud). Bowlby believed the mother-infant bond is crucial in humans for the survival of the child (like ethologist). A child near the mother can be fed, protected, trained and transported more effectively. Bowlby believed the attachment bond develops easily during a sensitive period, and after this time, it is impossible for the child to achieve true intimate emotional relationship (like ethologist). E.O. Wilson’s theory Sociobiology : A branch of biology that attempts to discover the evolutionary origins of social behavior. According to his theory, genes are selfish structures whose only interest is to ensure their own survival. When a characteristic is valuable for survival or reproduction, the genes that produce it are more likely to be passed along to the next generation—Darwin’s natural selection process. Sociobiologists believed that genes influence physical traits and social behaviors that are more adaptive for survival, thus both undergo the same natural selection process. Wilson suggested that genetic effects on social behavior are better understood at the level of culture or society, rather than of the individual. Evolutionary development psychology shares the general ethological emphasis on evolution and the selection of adaptive behavior, and with the sociobiologists’ specific concern with explaining the origins of behavior patterns. It includes the evolutionary origins of contemporary cognitive abilities and those that underlie social relations and interactions. Two themes characterize evolutionary developmental psychology : 1. The fit between the adaptational challenges faced by our ancestors across the millennia during which our present characteristics were selected, and those that confront contemporary humans. 2. The argument that the attributes that are adaptive and promote survival will vary with the developmental level of the organism.  Chapter 2 - Research Methods 2.1 - SCIENTIFIC RESEARCH Scientific research : The system of rules used by scientists to conduct and evaluate their research 2.1.1 - The Role of Theory Theory : A broad set of statements describing the relation between a phenomenon and the factors assumed to affect it. Law (principle) : A predicted relation between a phenomenon and a factor assumed to affect it that is supported by a good deal of scientific evidence. Hypothesis : A predicted relation between a phenomenon and a factor assumed to affect it that is not yet supported by a great deal of evidence. Hypotheses are tested in experimental investigations. Theories have two important roles in scientific research : 1. Organize research findings : They use theories to fit the information together into coherent explanations of the behaviors and processes being studied. 2. Guide new research : They indicate to investigators which hypotheses should be tested next. In child psychology, research is typically guided by underlying theory or theoretical orientation (not random). 2.1.2 Objectivity and Measurement Objectivity : A characteristic of scientific research ; it requires that the procedures and subject matter of investigations be formulated so that they could be agreed on by everyone. What is the importance of objectivity ? It allows any other scientist to conduct the same research in the same manner (and presumably arrive at the same results). It helps reduce potential sources of bias that could interfere in the research, like the experimenter’s personal beliefs or preferences regarding what results should be. How is objectivity obtained ? Well, in a research, the behaviors of the child must be observable, measurable and quantifiable. 2.2 - TYPES OF RESEARCH 2.2.1 - Descriptive Research Descriptive research : Research based solely on observations, without attempting to determine relations between the variables. It consists of simply observing or interviewing children or other significant people in their lives and recording information of interest. Researchers don’t typically make an attempt to manipulate things and observe consequences, but rather describe things that way they are. a) Observational Methods Naturalistic observation : The systematic observation of behavior in natural settings. ○ For example, researchers watch children interacting, playing or solving problems to answer certain research questions about said child. This method leaves room for bias of interpretation ; while some research might perceive a child's action one way, another might see it another way. For example, it is hard to understand the motive behind a child’s action. Steps are followed by researchers to minimize the bias, such as : Identification of the behaviors to be recorded + define precisely what constitutes an instance of the behavior. Training given to observers using this method. Assessment of two researchers watching the same episode of behavior and recording their observation independently (increase the accuracy of the observation) **Use of video recordings to review the accuracy of the observers’ data. Observer influences : The effects of knowing that you are being observed. How to minimize this influence ? Make the observers’ presence as inconspicuous as possible such as hiding the cameras. Structured observation : The observation of behavior in settings that are controlled by the investigator. For example, the experiment takes place in a laboratory setting, where researchers can control the physical aspects of the environment in which the child is being observed (the presences of certain toys). b) Interview Methods This method consists of collecting information through verbal reports, such as interviews or questionnaires. There are two types of interviews : Open-ended interviews : Children responding freely and in a conversational way ○ This type of interview studies the information qualitatively.  Structured interviews : children respond to a specific set of questions ○ This type of interview studies the information quantitatively. Interviews rely on the informant’s knowledge, memory and ability or willingness to communicate information. Thus, they may not always accurately reflect actual behavior. c) Case Studies This research method involves only a single individual, often with a focus on a clinical issue (rare disorder or new treatment approach). For example, the case of “Genie”. The major limitation of using only a single research participant is that the researcher must be very cautious about drawing conclusions from the case. 2.2.2 - Correlation Research Correlation research : Research based on identifying any systematic relations in the observations (measurement) without any intrusion or interference by the researchers. Variable : Any factor that can take on different values along a dimension (ex. physical characteristics like height, weight and age) or environmental aspects (ex. temperature, room size, distance and family size). Behaviors can also be variables and can vary along several dimensions, such as : Frequency : How many times a child asks the teacher for help. Intensity : How loudly a baby cries. Duration : How long a child practices the piano. Correlation : The relation between two variables, described in terms of direction and strength. Positive correlation : A correlation in which two variables change in the same direction. Negative correlation : A correlation in which two variables change in opposite directions. Correlation coefficient (r) : A number between +1.00 and -1.00 that indicates the direction and strength of a correlation between two variables. A coefficient of 0 means there is absolutely no correlation between the two variables. ○ For example, +.86 = strong positive correlation ; +.17 = weak positive correlation ○ For example, -.93 = strong negative correlation ; -.08 = weak negative correlation Scatter diagram : A graphic illustration of a correlation between two variables. **Correlation cannot be used to show causality between the variables.**  2.2.3 - Experimental Research a) Experimental research : Researched based on identifying the relation between just two variables, but unlike correlational research, it allows us to draw cause-and-effect conclusions about the variables. One variable is manipulated (altered/changed) and looks for any effects (changes) in the second variable. Independent variable : The variable in an experiment that is manipulated. Dependent variable : The variable that is predicted to be affected by an experimental manipulation. NOTE : Not all variables can be manipulated ; some variables may be characteristics of the participants themselves. For example, researchers interested in how children react to divorce cannot realistically conduct experimental research (would be an ethical complication). Other variables cannot be manipulated, even if there are no ethical implications of doing so. For example, researchers want to compare children of different linguistic backgrounds, or to compare boys and girls. Variables such as these cannot be manipulated, rather, researchers are forced to study participants as they find them. b) Quasi-experimental studies : Comparison of groups differing on some important characteristics. In this type of research, the groups are determined on the basis of an existing characteristic of the participants. Thus, the investigator has considerably less control over the independent variable and the conclusions that can be drawn are limited. Page 51. Disadvantages and advantages of the types of research  2.3 - STUDYING THE PROCESS OF DEVELOPMENT Method Description Usefulness Drawbacks Longitudinal The same group of children is Allows the researcher to study Attrition : the loss of individuals studied repeatedly at different changes as children age. in the study, which can occur for ages. a variety of reasons. Can be used to examine stability of behavior as well as effects of early Repeated testing can influence experiences. results. Issues and instruments may become outdated. Time-consuming and expensive. Cross-Sectional Groups of children of Relatively quick and low cost. Cannot be used to examine different ages are compared at stability and change. one point in time. No problems of attrition or repeated testing. Cohort effects : A problem in which people of a given age are affected by factors unique to their generation. **Can influence findings Cross-Sequential Combines cross-sectional and Allows both cross-sectional and Time-consuming and costly. longitudinal research. longitudinal comparison to be Children of different age made. groups are followed longitudinally. Allows researchers to examine for cohort effects. Microgenetic Intensive study of a small Allows examination of Repeated testing can influence number of children over a developmental changes that are results. brief period of time. discontinuous. Expensive. 2.4 - OTHER RESEARCH TACTICS 2.4.1 - Cultural Research Cross-cultural Research : Research designed to determine the influence of culture on some aspect of development and in which culture typically serves as an independent variable. (Most common) A variety of methods are used in this type of research like interviews, observations, archived reports, laboratory tasks and psychological tests. It is important to test the universality of a phenomenon as it allows us to determine whether patterns of a behavior are universal to humans or results from factors specific to a particular culture/ individuals.  A drawback from this type of research are the devising studies that measure the same behavior in different cultural contexts. Cultural Psychology : Study of a single culture from the perspective of members of that culture, the goal being to identify the values and practices important to the culture. Ethnographic Methods : Study in which the researcher lives as a member of culture and gathers information about the culture through various techniques over an extended period of time. 2.4.2 - Comparative Research Comparative research : Research conducted with non-human species to provide information relevant to human development. It allows psychologists to conduct studies that could be prohibited with humans for ethical research. 2.4.3 - Psychophysiological Methods Psychophysiological methods : Any research method in which the dependent variable is a physiological measure and the independent variable is behavioral or mental. For example, in babies we can measure their heart, breathing or sucking rate to access the preferences of a stimuli. Electroencephalograph (EEG) allows researchers to measure electrical activity in the brain, and can be useful to identify what regions of the brain are activated by specific stimuli. Neuroimaging techniques, where computer programs are used to convert data taken from brain-scanning devices into visual images of the brain. Functional magnetic resonance imaging (fMRI) allows researchers to watch the brain as an individual carries out various tasks. 2.5 - ETHICAL ISSUES 2.5.1 - Potential Risk In experiments, issues are relatively rare, but possible. Such, it is the duty of the researcher to describe the potential risk to the participants before starting the research. This includes : physical injury, psychological harm and violations of privacy (access to school record or if data becomes public knowledge). 2.5.2 - Safeguards The development of safeguards were designed to avoid or eliminate potential risks. They are now part of modern research procedures. The Canadian Code of Ethics for Psychologists, the Ethical Principles of Psychologists and Code of Conduct, and the Ethical Standards for Research with Children are all examples. According to the Ethical Standards for Research with Children there are 14 specific principles : 1. Nonharmful procedure 2. Informed consent 3. Parental consent (legal consent of parents or legal guardian) 4. Additional consent (consent of any person whose interaction with the child is the subject of study) 5. Incentive (fair + does not exceed the range of motivation that the child normally experiences) 6. Deception (withheld info essential to the conduct of the study must be investigated and deemed correct) 7. Anonymity (researchers must obtain permission from right authorities to access institutional records) 8. Mutual Responsibility (clear agreement between investigator and parents that defines responsibilities) 9. Jeopardy (info that comes up during the study that could jeopardize the child’s well-being must be told) 10. Unforeseen consequences (employ measures to correct undesirable consequences for the participants) 11. Confidentiality (investigator must keep in confidence all information obtained in the research) 12. Informing participants (investigator should clarify any misconception that aries after the data collection) 13. Reporting results (caused taken in reporting results, making evaluative statements or giving advice) 14. Implications of findings (must be mindful of the social, political and human implications of their research and the presentation of findings)  Chapter 3 - Genetics : The Biological Context of Development 3.1 - MECHANISMS OF INHERITANCE 3.1.1 - Cell Division Chromosomes : Chemical strands in the cell nucleus that contain the genes. The nucleus of each human cell has 46 chromosomes, with the expectation of the gametes, which have 23. Autosomes : The 22 pairs of human chromosomes, other than the sex chromosomes (gametes). Sex chromosomes : The pair of human chromosomes that determines the sex (Females = XX ; Male = XY) Cells can be divided into two types : body cells and germ cells These cells are distinguished as they can reproduce and the roles they play in hereditary transmission Mitosis : The process by which body cells reproduce, resulting in two identical cells. Meiosis : The process by which germ cells produce four gametes (sperm or ova), each with half the number of chromosomes of the parent cell. Crossing over : The exchange of genetic material between pairs of chromosomes during meiosis. 3.1.2 - Inside the Chromosomes Gene : A segment of DNA on the chromosome that codes for the production of proteins. The basic unit of inheritance. Deoxyribonucleic acid (DNA) : A stair-like, double helix molecule that carries genetic information on chromosomes (discovered by James Watson and Francis Crick). Rungs are composed of four bases : adenine (A), thymine (T), guanine (G), and cytosine (C). ○ Each rung (called a nucleotide), consists of a pair of these bases linked together. Two types of pairing exist : A-T or G-C. Base pair : The unit of length of the double-stranded DNA molecule. Allèles : Genes for the same trait located in the same place on a pair of chromosomes. There are two types of genes : Structural genes that guide the production of proteins. Regulator genes that control the activities of the structural genes, thus they can selectively suppress the production of protein so that cells in a particular organ only produce the proteins appropriate for it. ○ They can also turn structural genes on and off at different points in the development. 3.1.3 - The Human Genome Project Project launched by James Watson in 1989 with the purpose to determine the sequence of 3 billion base pairs that make up human DNA and to identify human genes. **18 countries participated** Discovered different variations in size between chromosomes + genes with respect to the number of base pairs they consist of. ○ X chromosome is bigger (carries more genes) than the Y chromosome  Discovered we had fewer genes than once believed—about 20,000 to 25,000—in contrast to earlier estimates of 140,000. Project helped identify faulty genes responsible for diseases, thus opening the door for research into genetic treatments for inherited disorders. 3.1.4 - Mendel’s Studies Project involved mating the purple and white flowers (parent plants) together to better understand the hereditary transmission. Through many experiments, Mendel developed the theory that each observable trait, which we know are a pair of genes (alleles), one inherited from each parent. Phenotype : The characteristic of a trait that is expressed or observable. It results from an interaction of genotype and environment. Genotype : The arrangement of genes underlying a trait. Mendel’s model introduces the principle of dominance : the alleles of a trait are not equal, and one usually dominates the other. Dominant gene : A relatively powerful allele whose characteristics are expressed in the phenotype, regardless of the allele with which it is paired, Recessive gene : A relatively weak allele whose characteristics are expressed in the phenotype only when it is paired with another recessive gene. Mendel’s theory also introduced the principle of segregation : each inheritable trait is passed on to the offspring as a separate unit. And the principle of independent assortment : traits are passed on independently of one another. Revision of Mendel’s principles : Polygenic inheritance : A trait is determined by a number of genes. Incomplete dominance : The dominant gene does not completely suppress the effect of a recessive gene, which is then somewhat expressed in the phenotype. Codominance : Both alleles are dominant and each is completely expressed in the phenotype. Genomic imprinting : The allele from one parent is biochemically silenced and only the allele from the other parent affects the phenotype. 3.2 - GENETIC AND CHROMOSOMAL DISORDERS 3.2.1 - Hereditary Disorders Dominant traits disorder Typically disappear from the species because the affected people usually do not live to reproduce Except for a few cases like Huntington’s disease which becomes active later in life) Recessive traits disorder It is not guaranteed to affect the individual, thus may never present any symptoms. For example : Tay-Sachs’s disease or Phenylketonuria or Sickle-cell anemia Intellectual disability : A disorder characterized by limited intellectual and adaptive functioning (also sometimes referred to as mental retardation). X-linked traits disorder Results from recessive genes located on the X chromosome, leaving males more vulnerable to them. For example : Hemophilia or Fragile X-syndrome or Cystic fibrosis 3.2.2 - Structural Defects in the Chromosome Autosomal disorder Down Syndrome or trisomy-21 ○ Age of the mother can increase the risk of Down Syndrome, but most of the time it is the father that contributes the third chromosome. Cat’s Cry Syndrome which occurs from the deletion of a small amount of genetic material. Sex chromosome disorder The process for which an embryo has an unusual arrangement of sex chromosomes and survives in utero (spontaneous abortion performed by uterus did not work). For example : Turner’s syndrome or Klinefelther’s syndrome (XXY or XYY) 3.3 - STUDYING THE EFFECTS OF GENES ON BEHAVIOUR 3.3.1 - Family Studies This approach asks whether the phenotype similarity on some trait follows from the genotypic similarity among the people being compared. This approach can be of value, but sometimes it points out characteristics that might have genetic components and so encourage more definitive research using a more rigorous method. Difficulty in interpreting family studies because either genes or environment could account for patterns found during the research. 3.3.2 - Adoption Studies This approach is designed to address the difficulty in whether genes or environment account for found patterns. A major study that employed this approach is the Colorado Adoption Project. Longitudinal study with about 250 families with adopted children, and in comparison 250 families with biological children studying intelligence. Study shows stronger correlation between the score of biological children and parents/siblings than between children and their adoptive parents ○ This clearly supports a role for genetic processes. The adoption approach also provides evidence about the origins of problems in development in other research. Example, kids with behavior problems most likely have parents with the same issues. This study allowed a third finding : a positive relation between the adoptive parents’ disciplinary practices and the biological parents’ history of psychiatric problems. ○ Children of parents with psychiatric problems were more likely to encounter harsh disciple from their adoptive parents The critical link hypothesized was the child since… 1. The children initially inherited their behavior problems from their biological parents. 2. These problems then evoked responses (harsh discipline) from their adoptive parents. 3. The adoptive parents’ disciplinary practices then served to maintain the childrens’ problem behaviors. 3.3.3 - Twin Studies Identical/ monozygotic twins : Twins who develop from a single fertilized ovum and thus inherit identical genetic material. Fraternal/ dizygotic twins : Twins who develop from separate fertilized ova and who are no more genetically similar than any other siblings.  The logic of the twin study approach assumes that fraternal twins share an environment that is as similar as the environment shared by identical twins. Researchers then look at a particular trait or behavior displayed by the sets of twins. If the trait is more similar in the identical twins than the fraternal twins, we could conclude that the greater similarity are the results means the greater similarity are their genes. Twins studies have also been used to address a variety of personality issues. For example, if one identical twin gets divorced, the chances the other twin does the same are greater. Behavior geneticists use twins to examine whether genetic influences underlie certain changes we see in children’s development and behavior. Development pacing : The rate at which spurts and plateaus occur in an individual’s physical and mental development. 3.3.4 - Combined Twin-study and Adoption-study Approaches This combined approach is the most desirable, but it’s also the most difficult to use because so few twins are raised apart. The best-known project to use this approach is the Minnesota Study of Twins Reared Apart. Comparison of 135 pairs of twins with a handful of separated-twin studies. The study shows strong evidence of a genetic contribution to differences in IQ, such as even when reared apart, identical twins correlate substantially in IQ (greater than fraternal twins living in the same home). Rear apart identical twins are also similar on a variety of personality characteristics. An important limitation to the combination of both studies is that because of the selective placement practices followed by most adoption agencies, the homes in which adopted children are placed then to be relatively homogeneous (similar). 3.4 - MODELS OF GENE-ENVIRONMENT INTERACTION Behavior genetics : The field of study that explores the role of genes in producing individual differences in behavior and development. All contemporary psychologists believe that genes (nature) and environment (nurture) interact to determine human behavior, but differ as to which factor has a bigger influence. 3.4.1 - Gottesman’s Limit-Setting Model Model suggests that genes interact with the environment by setting upper and lower limits of our development. Reaction range : The range of ability or skill that is set by the genes. The value achieved within this range is determined by the environment. 3.4.2 - Scarr’s Niche-Picking Model Model suggests that genes actually play a role in determining the kind of environment the child experiences. Passive gene-environment correlation : Situation in which genes and environment affect development similarly because the genes the child receives from the parents are compatible with the environment the parents provide. Occurs during infancy Evocative gene-environment correlation : Situation in which genes and environment affect development similarly because genetically set predispositions of the child elicit compatible experiences from the environment. Occurs as children get older Active gene-environment correlation : Situation in which genes and environment affect development similarly because children seek out experiences that are compatible with their genetic predispositions. Occurs as children gain more independence Scarr claims genetic influences actually grow stronger with age, as children become better able to actively recruit the environment their genes bias them toward. 3.4.3 - Plomin’s Environmental Genetics Model Model that believes childrens’ developmental outcomes are related to their family environment for two reasons : 1. Children share many genes with their parents, who in return provide the environment for their children. 2. Children evoke from their parents the sorts of responses and surroundings that suit their genes. His model is not limited to child-parent interactions, but also extends to other family members. Non-shared environment : A concept used in behavior genetics to refer to presumed aspects of the environment that children experience differently. In other words, Plomin’s answer to why siblings behave and develop so differently from one another is because although these children live in the same family, they do not necessarily experience the same environments. Oftentimes, parents treat their childrens differently, and children frequently react to the same family events and experiences in different ways. His theory believes that the similarities in siblings result mostly from genetics, and in contrast, the environment contributes very little. The first evidence is that adoptive siblings are considerably less similar than are biological siblings, thus suggesting a common environment is not enough. The second evidence, adoptive siblings are more similar in childhood than in adolescence, even though by that point they have lived together for longer. A further finding that is relevant to Scarr’s and Plomin’s is that psychological characteristics of an adopted child becomes similar to those of the biological mother and less to the ones of the adoptive mother as time goes. 3.4.4 - Bronfenbrenner and Ceci’s Bioecological Model The model assigns much more importance to the environment. They agree that children’s genes influence their development and that, to some degree, they do so by steering the environment in the right direction. Proximal processes : Interactions between the child and aspects of the microsystem that have positive effects on psychological functioning and that help maximize expression of the child’s genetic potential. These interactions must take place regularly and for a prolonged period of time. This allows a child's genes to use the experiences to achieve their ends, and, as a result, the child reaches its maximum genetic potential. Proximal processes are valuable in both high and low quality environment, but in different ways ○ Interactions have the best opportunity to help the child develop their fullest abilities in a stable and rich with resources environment. ○ In a disorganized and disadvantaged environment, these interactions can prevent undesirable outcomes that otherwise could have occurred. On the contrary if proximal processes are weak or missing in the child’s life, the genes cannot fully express themselves, and the child’s development will remain below its potential.  Chapter 4 - Prenatal Development 4.1 - STAGES OF PRENATAL DEVELOPMENT 4.1.1 - Conception Conception : The combining of the genetic material from a male gamete (sperm) and a female gamete (ovum) fertilization. Zygote : A fertilized ovum. Prenatal development begins at the conception/ fertilization where the zygote receives 23 chromosomes from each parent (so 46 in total), to form a new genetically unique persone. Cycle of conception : 1. Ovum is produced (by left or right ovary) and released to begin its travel through the fallopian tube. 2. Ovum is capable of being fertilized by a sperm (liable for 2-3 days). **Only 1 penetrates the ovum 3. Once penetration has happened, the genetic material of the sperm and ovum merge to form the zygote. 4.1.2 - The Period of the Zygote (conception to 2 week) The zygote multiplies rapidly in the next four days. It starts off as a solid mass, but gradually changes into a hollow sphere as it prepares for implantation in the wall of the uterus. The cells start to specialize, some forming an inner cell mass that will become the embryo, and other forming important structures that will support the embryo’s development. The implantation takes about a week, where the zygote settles into the blood-enriched lining of the uterus. 4.1.3 - The Period of the Embryo (3 to 8 week) Embryo : The developing organism from the third week, when implantation is complete, through the eight week after conception. All major internal and external structures form during this period. These weeks are the most delicate of the pregnancy and when the growing embryo is most vulnerable to threats from both internal and external environments. In the third week, the inner cell mass differentiates into three layers which all body structures will emerge : Endodermal layer : Develops into internal organs and glands. Mesodermal layer (middle) : Develops into muscles, cartilage, bone, sex organs and heart. Ectodermal layer : Develops into the nervous system (sensory part of the eyes, nose, ears, skin and hair). In the fourth week, the embryo assumes a curved form (results of rapid cell multiplication in some locations). Throughout the next weeks, the embryo’s limbs, brain and heart continue to develop rapidly. By the end of this period the embryo has some distinctive human features. All internal and external structures have formed (is now a complex organism). The prenatal environment Three major structures arising from cells : Amniotic sac : A fluid-containing watertight membrane that surrounds and protects the embryo/fetus.  Placenta : An organ that forms where the embryo attaches to the uterus. It exchanges nutrients, oxygen, and wastes between the embryo/fetus and the mother, through a very thin membrane that does not allow the passage of blood. More specifically, the exchange is done in the placental villi. Umbilical cord : A soft cable of tissue and blood vessels that connects the fetus to the placenta. 4.1.4 - The Period of the Fetus (9 to 38 week) The principal changes in this period includes further development of the organ structures and an increase in size and weight. External changes The head grows less than other parts of the body to reproportion the baby. The facial features become more human looking, as the eyes move from the sides of the head to the front. Other changes include : Eyelids shutting Nails and hair growing Bone structure begins to support  Internal changes The brain is organized into functional subdivisions + other internal organs continue to develop. Sexuel development becomes apparent in males (sexual organs appear). For females, the ova, fallopian tubes, uterus and vagina develop (16th week). Early signs of behavior Fetal activity begins in the 3rd month when it is capable of forming a fist and wiggling toes (mom doesn’t feel it). The fetus will respond to environmental stimulation. In the 4th month, the eyes are sensitive to light. In the 5th month, the baby starts kicking and turning. In the 6th month, the fetus starts to exhibit a sucking reflex when the lips are touched. Toward independence Age of viability : The age (23 or 24 weeks) at which the infant has a chance to survive if born prematurely. The major obstacles to independent life for a fetus born prematurely are : The immaturity of the air sac of the lungs. The inability to digest food. The inability to control body temperature (fat has not formed yet to assist with temperature regulation). Alternative methods of conception : in vitro Fertilization (IVF) and donor insemination. 4.2 - TERATOLOGY Teratology : The study of the effects of teratogens on development. Teratogen : An agent that can cause abnormal development in the fetus (in Greeks it means “monster”). 4.2.1 - Historical Ideas The birth of malformed babies probably gave rise to some creature of Greek mythology. Although monsters were sometimes idolized at the time, malformed children were often put to death. Some mothers and midwives who delivered malformed babies were sometimes put on trial for witchcraft. In the 1900s, people started realizing that diseases or circumstances cause malformation in babies. 4.2.2 - General Principles Several principles capture important features of how teratogens act : 1. A teratogen’s effect depends on the genetic makeup of the organism exposed to it. For example, the impact of thalidomide on infants that don’t reflect in animals. 2. The effect of a teratogen on development depends partly on timing. For example, x-ray exposure that the father experienced many weeks before conception can affect the fetus. When the zygote has been implanted into the wall of the uterus, many substances in the mother’s bloodstream can pass through the placental barrier and into the blood of the embryo. Teratogen can produce organ malformation from 3-8 weeks after conception since it is the period when the organs are forming. After they have formed, teratogens primarily produce growth retardation or tissue damage. The organ affected by a teratogen depends on which one is forming at that moment. 3. The effect of a teratogen may be unique. 4. The abnormal development caused by teratogens may be severe.  Teratogens may include malformation or limbs or other parts of the body, growth retardation, functional and behavioral disorders, or even death. 5. Teratogens differ in how they gain access to the fetus. 6. The likelihood and degree of abnormal development increase with the level of exposure to the agent. 4.2.3 - Types of Teratogens Teratogens can take several forms : drugs, diseases or hazards from the external environment. Teratogens Potential Effect Therapeutic Drugs ➔ Aspirin Miscarriage and bleeding during pregnancy ➔ Barbiturates Respiratory problems ➔ Diethylstilbestrol (DES) Genital abnormalities ➔ Phenytoin Heart defects and growth retardation ➔ Streptomycin Hearing loss ➔ Tetracycline Bone growth and staining of teeth ➔ Thalidomide** Deformed limbs, sensory deficits, defects in internal organs and death Street Drugs  ➔ Cocaine and crack Growth retardation, premature birth, irritableness, withdrawal symptoms ➔ Heroin and methadone Growth retardation, premature birth, irritableness, withdrawal symptoms, SIDS ➔ Marijuana and Nicotine Exaggerated startle response, fine motor tremors, poor habituation to visual stimuli, problem in area of executive function Alcohol and Tobacco ➔ Alcohol Brain and heart damage, growth retardation, intellectual disability, FAS ➔ Smoking Growth retardation, prematurity Infections ➔ HIV Facial malformation, AIDS ➔ Cytomegalovirus Deafness, blindness, abnormal head and brain growth, intellectual disability ➔ Herpes Simplex Intellectual disability, eye damage, CNS damage ➔ Rubella Intellectual disability, eye damage, deafness and heart defects ➔ Syphilis and Gonorrhea CNS damage, deformities of the teeth and skeleton, death ➔ Toxoplasmosis Abnormalities in brain and head growth Environmental Hazards ➔ Lead Miscarriage, neuromuscular problems and intellectual disability ➔ Mercury Neurological problems, abnormal head and brain growth, intellectual disability ➔ PCBs Growth retardation and skin pigmentation ➔ Radiation Leukemia, abnormal brain and body growth, cancer, genetic alteration, miscarriage Fetal alcohol syndrome (FAS) : A set of problems in the infant and child caused by mother’s use of alcohol during pregnancy. Fetal alcohol spectrum disorder (FASD) : The differing degrees of effects that may result from prenatal alcohol exposure (more common than FAS). 4.3 - NATURAL CHALLENGES 4.3.1 - Nutrition The weight gained during pregnancy is due to increases in the weight of the mothers tissues, as well as the weight of the fetus, placenta and amniotic fluid. Maternal malnutrition can have devastating effects on the fetus. It can cause : Brain to malform (weighs less) Spontaneous abortion Infant death Congenital defects Interference with the development of the placenta (less nutrients available for the fetus) Malnourishment is often accompanied by inadequate housing and sanitation, and inferior education and health care, as well as the daily stress of poverty. Food quantity is not the only issue in maternal nutrition. A pregnant woman and her fetus have special dietary needs (proteins, essential fatty acids, vitamins and minerals are important). 4.3.2 - Maternal Experiences and Stress According to research, high levels of anxiety have been associated with newborn irritability, feeding and sleep problems during infancy, and behavioral problems starting at 4 years old. It has also been associated with a heightened probability of congenital physical anomalies : heart defects and cleft palate. 4.3.3 - Prenatal Age The optimal time for childbearing falls between the ages of 20 and 34 with the best time within this range being ages 25-29.  For the mothers, increased maternal age is associated with a higher chance of giving birth to a baby with Down syndrome. It has also been shown that older mothers are more at risk for preterm birth, difficulties during delivery, and both infant and mother mortality. For fathers, increased paternal age is associated with frequency of mutation in the sperm that can cause problems. A genetic disorder related is achondroplasia, a dominant mutation that causes bone deformities. In teen pregnancy the risks are complications in the growth, preterm birth and low birth weight. 4.4 - PREVENTING, DETECTING, AND TREATING BIRTH DEFECTS 4.4.1 - Prevention At the moment, not all birth defects can be prevented as some are not controllable and the cause of others are not even known. Genetic counseling : The practice of advising prospective parents about genetic diseases and the likelihood that they might pass on defective genetic traits of their offspring. DNA testing of their blood may determine whether they are carriers of a defective gene. 4.4.2 - Screening for Abnormalities Significant progress has been made in detecting problems in newborn infants, which opens up the possibility for ealy treatment. For example, progress in phenylketonuria screening in Canada. Ultrasound imaging : A non-invasive procedure for detecting physical defects in the fetus. Amniocentesis : A procedure for collecting cells that lie in the amniotic fluid surrounding the fetus. These cells can be examined for chromosomal and genetic defects. Needle inserted in the mother’s abdomen Chorionic villus sampling : A procedure for gathering fetal cells at the site of the developing placenta earlier in pregnancy (before amniocentesis). Tube inserted in the mother’s abdomen or cervix Endoscopic Fetoscopy : A procedure allowing to visualize the fetus, obtain fetal tissue samples, or perform fetal surgery. Fibre-optic inserted into the uterus through the abdomen or cervix In vitro screening : A procedure where the embryo is screened in the test tube before they are implanted in the mother’s uterus. 4.4.3 - Treatment Medical therapy : The intervention provided by healthcare professionals to address pathological conditions, aiming to alleviate symptoms or cure the disease.  For example, providing extra vitamins, dietary interventions, treating illnesses in the mother and providing therapy directly to the fetus. Fetal surgery : A procedure on the fetus while it is still developing in the uterus. Fetal gene therapy : A technique that uses modified genes (in a lab) to treat, prevent or cure diseases and medical disorders. 4.4.4 - Ethical Considerations Many techniques and treatments raise difficult ethical question, this includes : 1. The ability to diagnose abnormal development 2. The treatment of disorders while babies are still in the womb (fetal surgery and gene repair) 3. The decision regarding the health and life of a fetus or infant Chapter 5 - Physical Development : Birth, Motor Skills and Growth 5.1 - BIRTH AND THE PERINATAL PERIOD 5.1.1 - Labour and Delivery Perinatal period : The events and environment surrounding the birth process. **Begins with birth ➔ Birth typically occurs at 38 weeks and lasts about 16h (first child). ➔ Fetus initiates the birth process by secreting chemical messages that induce contractions of the uterus. ➔ Variations of birth include caesarean section, a surgical delivery of the fetus directly from the uterus, performed when normal delivery is prohibited. Fetal distress : A condition of abnormal stress on the fetus during birth (ex. abnormal fetal heart rate). There are three stages to the birth process : 1. Uterine dilation 2. Fetus passes through the cervix 3. Delivery of the placenta and other membranes 5.1.2 - Cultural Attitudes Towards Birth Cultural variations exist in attitudes towards pregnancy and birth. ➔ Western society treats pregnancy as an illness. ◆ Follow a medical model of regular doctor visits, birth in hospital, and drugs for pain relief. ➔ Other cultures view pregnancy as an everyday occurrence. ◆ Follow a natural model where few medical interventions and alternative pain relief are employed. 5.1.3 - The Concept of Risk Babies may face two different risks : major physical malformations and developmental delays for cognitive or social problems. “At risk” : Babies who have a higher likelihood of experiencing development problems. Indicators of “at risk” status :  a) Maternal and family characteristics Poor prenatal care (85% of the risk happens in the prenatal period) Maternal nutrition, drug use, socioeconomic status, education, etc b) Physical compromise of the newborn Anoxia : A deficit of oxygen to the cells that can produce brain or other tissue damage. Preterm : Babies born before the end of the normal gestation period (38 weeks). Small for gestational age (SGA) : Babies born at a weight in the bottom 10% of a particular GA. **Note : A baby can be both preterm and small for gestational age. Recent use of various drugs (ex. perinatal steroids and inhaled nitric acid) have shown to mitigate any neurodevelopmental impairment in low-birth-weight babies. c) Newborn performance on behavioral assessment The Apgar Exam focuses on 5 vital functions such as heart rate, respiration, muscle tone, pain response, skin color. The Brazelton Neonatal Behavioral Assessment Scale focuses on 4 groups such as attention and social responsiveness, muscle tone and physical movement, control of alertness, physiological responses to stress. d) The role of the later environment A factor in a baby’s developmental progress is the quality of the relationship parents-baby. At-risk babies often pose challenges to this relationship. Investigators have observed that parents treat their preterm children differently, even after apparent differences from full-term babies have disappeared. Prematurity stereotyping : Tendency to expect negative behaviour from premature infants. 5.2 - THE ORGANIZED NEWBORN 5.2.1 - States of Alertness Recordings of brain electrical activity (EEG) reveal that sleep-waking states change across the lifespan. The duration of sleep per night decreases with age. The percentage of time spent in rapid eye movement (REM) sleep decreases with age. ➔ The function of REM sleep is unknown. ➔ Suggestions have been made that REM represents an interval activation process for brain neurons. Sudden Infant Death Syndrome (SIDS) : The sudden death of an otherwise healthy infant under the age of 1. 5.2.2 - Newborn Reflexes  Reflex : An automatic and stereotyped response to a specific stimulus. While some reflexes are present throughout life, some reflexes are evident at birth, but disappear by age one. Rooting reflex : Tactile stimulation of the cheek elicits a head turn towards the stimulus. Palmar reflex : Pressure by an object on the palm of the infant elicits a grasping of the object. Stepping reflex : Feet placed on a flat surface, newborn makes stepping motion like walking. Moro reflex : Loss of head support elicits a motor sequence of embracing. 5.2.3 - Congenitally Organized Behaviours They are early behaviours of newborns that do not require specific external stimulation and are more adaptable than simple reflexes. Looking : Infants will engage in examining their surroundings even when they are not externally stimulated. Sucking : Infants suck spontaneously, when not hungry, it serves as an exploration tool and to buffer pain and overstimulation. Crying : Serves not only to convey hunger, but also emotions ; in addition, crying influences early social relationships. 5.3 - MOTOR DEVELOPMENT Postural development : The increasing ability of the baby to control parts of its body, especially the head and trunk. Locomotion : The movement of a person through space, such as walking and crawling. Prehension : The ability to grasp and manipulate objects with the hands. 5.3.1 - Principles and sequences Motor skills development proceeds in… Proximodistal direction : Tendency of body parts to develop from center to extremities (near to far). Cephalocaudal direction : Tendency of body parts to mature from head to foot (head to tail). 5.3.1 - The Nature and Nurture Motor-Skills Development Nature states that motor skills are genetically preprogrammed. Nurture states that environmental influences affect motor development. Dynamic Systems Approach : Thenlen’s model of development of motif skills in which infants motivated to accomplish a task create a new motor behaviour from their available physical abilities. Also claims that physical resources interact with the environment to determine timing and direction of development. 5.4 PHYSICAL GROWTH Growth trends show different patterns across genders (about 2 years between female and male growth). Growth rates have changed over history. Catch-up growth : Accelerated growth that follows a period of delayed/stunting growth resulting from disease and malnutrition. Skeletal maturity (bone age) : The degree of maturation of an individual as indicated by the hardening of the bones. 5.4.1 - Puberty Puberty : Period in which chemical and physical changes occur that enable sexual reproduction. A negative body image due to puberty changes affect boys and girls of all ages. However, research shows early maturing boys are less likely than other groups to develop anxiety, depression, etc due to those changes. 5.4.2 Factors that Affect Growth and Maturation a) Heredity Genetic factors influence maturation and growth. In research, identical twins have more similar spurts and lags in growth and weight than fraternal twins. b) Nutrition A child’s nutrition is associated with measures of growth and development like anorexia, bulimia, obesity and binge-eating disorder. Anorexia nervosa : A severe eating disorder, usually involving excessive weight loss through self-starvation; most often found in teenage girls. Bulimia nervosa : A disorder of food binging and sometimes purging by self-induced vomiting; typically observed in teenage girls. Obesity : A condition of excess fat storage; often weight more than 20% over normal ideal weight. c) Abuse and psychological trauma Psychological disturbances or maltreatment can lead to failure-to-thrive syndrome. Chapter 6 - Neural and Brain Development 6.1 - METHODOLOGICAL ISSUES Neuroimaging techniques : Technologies and methods that enable scientists to generate “structural” and “functional” maps of brain activity through measurements of changes in either the brain’s metabolism, blood flow, or electrical activity. There are three categories : 1. Measure electrical brain activity 2. Distinguish physical structure of brain 3. Assess the functional and metabolic activity of the brain 6.1.1 - Measuring the Brain’s Electrical Activity Electrodes placed on the scalp to generate maps of neural activity. There are two types of recording brain activity : Spontaneous Electroencephalography (EEG) measures rhythms of electrical activity of neurons under stimulus conditions. Event-related Potentials (ERP) measures electrical activity of specific brain areas in response to a particular stimulus or action. Magnetoencephalography (MEG) measures the electrical currents in the brain under the magnetic field generated. 6.1.2 - Assessing the Brain’s Anatomical Structure Structural Magnetic Resonance Imaging (MRI) forms anatomical structure images of the brain using a large magnetic field that interacts with molecules in the body. Non-invasive, no radiation used and harmless. Diffusion Tensor Imaging (DTI) measures the diffusion or movement of water molecules through neural tracts that connect brain structures. 6.1.3 - Mapping the Functional Structure of the Brain Positron Emission Tomography (PET) measures the activity of brain areas through the injection of radioactive positron-emitting isotopes. Functional Magnetic Resonance Imaging (fMRI) measures the level of oxygenated blood taken up by active brain areas. No radioactive substance is used. Near Infrea-Red Spectroscopy (NIRS) measured the absorption and scatter by blood oxygen in the brain using infrared light. 6.2 - THE NEURON : THE BUILDING BLOCK OF THE BRAIN 6.2.1 - Structure of the Neuron Neurons : The nerve cells in the brain that transmit activity through axons and dendrites. Dendrite : Short fibres which receive activity from another cell and transmits that activity to the cell body. Axon : Long fibre which conducts activity from the cell to other cells. Myelin : A sheath of fatty material that surrounds/insulates the axon, resulting in faster transmission of activity. Glial cell : A cell that wraps itself around the axon. Synapse : Small space between neurons where neural activity is communicated from one cell to another. Neurotransmitter : A chemical that transmits electrical activity to one neuron, to synapse, to another neuron. Synaptic vesicles : Structures near the end of the axon where neurotransmitters are stored. There are 4 neurotransmitter systems : 1. Noradrenaline 2. Dopamine 3. Serotonin 4. Cholinergic 6.2.2 - Organizational Structure of Neurons in the Brain 6.2.3 - Development of Neural Structure in the Brain Cell Production - First stage This stage of development is critical, however it is also a very sensitive period for brain development due to… ➔ Teratogens (ex. HIV, rubella and alcohol), which disrupts the cell production between the the 6th and 18th week after conception Underproduction of cells can occur which results in microencephaly (small brain) ; has been linked to fetal-alcohol syndrome. Overproduction of cells can also occur resulting in macroencephaly (large brain) ; has been linked to autism. Cell death/Apoptosis is the process to eliminate neurons (more cells produced prenatally than needed postnatally). Cell Migration - Second stage  In this stage, the brain cells migrate to their intended locations. To processes are involved in the migration : 1. Passive displacement where produced cells push out previously produced cells farther from the proliferative zones; results in an “outside-in” neural pattern. 2. Active cell migration where newly produced neurons use goal cells as guides to move past previously produced cells (cells move greater distances than in the other process). The final location of the migrating cells is determined by a chemical attraction with the target location; results in an “inside-out” neural pattern. Migration of neurons is completed by 7 months of gestation. As the migration occurs and is completed during gestation, the process and proper formation of the brain structures are sensitive to disruption causing different effects on the development. Cell Elaboration and Differentiation - Third stage It is at this stage that extensive networks are formed, and continue to do so until 24 months after birth. Myelination - Fourth stage It is at this stage that we see an increase in speed and efficiency of transmitted signals. 6.3 - BRAIN STRUCTURES 6.3.1 - Organization and Function of Brain Structures Brainstem : Lower part of the brain (incl. Medulla, pons and cerebellum) which controls basic bodily functions. Midbrain : Structure that controls breathing and swallowing, also the reflexive part of the auditory and visual systems. Cerebellum : Structure involved in motor control and learning, attention, language, and regulating emotional responses. Cerebrum : Includes both hemispheres of the brain and the interconnections between them. Corpus collosum : Bundle of nerves that connect the left and right hemisphere of the brain. Cerebral cortex : Thin sheet of grey matter that covers the brain. 6.3.2 - Cerebral Lobes and Functions 6.4 - DEVELOPMENT OF THE MAJOR STRUCTURES AND FUNCTION OF THE BRAIN 6.4.1 - Development of Hemispheric Specialization The right hemisphere of the brain… ➔ Controls input and movements on the left side of the body ➔ Specialized for images, and spatial and mathematical tasks The left hemisphere of the brain… ➔ Controls input and movements on the right side of the body ➔ Specialized in words, language and verbal memory processes There are three models for describing the development of hemispheric lateralization Biased gene : Inequality in the hemispheres at birth due to genes that are inherited. Biased brain : Inequality in the hemispheres at birth due to the brain neuroanatomical differences. Biased head : Inequality in the hemispheres at birth due to the infants’ tendency to shift their heads to one side limiting the range of stimulation each hemisphere receives. 6.4.2 - Development of Cortical Function The frontal lobe is the last to mature compared to other areas. 6.4.3 - Brain Plasticity Plasticity : Changes in the brain structure and function as a result of experience (ex. injury). Plasticity is a fundamental element to the course of brain development. The effect of experience on synaptogenesis and brain development comes in two forms : 1. Experience-expectant synaptogenesis : Mecanisme where synapse are formed, maintained and pruned based on experiences that are typical for that species. Given the same expected environment, all members' brains will develop the same capabilities. 2. Experience-dependent synaptogenesis : Changes in brain structure and function because of experience.  Chapter 7 - Sensory and Perceptual Development 7.1 ISSUES IN THE STUDY OF PERCEPTUAL DEVELOPMENT Sensation : The detection of sensory information. Perception : The interpretation of sensation. It’s the organization and understanding of the meaning of sensations. Attention : The selective perception. It’s the focus on certain stimuli while ignoring others. Infancy is the focal stage as most perceptual development is completed by the end of that stage of life. Nature versus Nurture question on perceptual development Nurture theorists’ explanation for perceptual development is on experience and formation of associations. For example, repeated exposure to faces leads the infant to associate nose, eyes and mouth as all required for a complete mouth. Nature theorists’ explanation for perceptual development is on the biological capabilities of the infant. Other theorists have an interactionist perspective on perceptual development, such nature and nurture both play a role. 7.2 TOUCH AND PAIN, SMELL AND TASTE, MOTION AND BALANCE 7.2.1 - Touch and Pain According to research, the sensitivity to touch can be demonstrated in the womb. Pain can be measured in young children using the Child Facial Coding System. Tactile stimuli (touch) elicit a variety of reflexes in the newborn (ex. rooting and palmar reflexes). Haptic perception : The perceptual experience that results from active exploration of objects by touch. 7.2.2 - Smell and Taste Infants are sensitive to both smell and taste at birth, reacting to pleasant and repugnant orders. The various tastes will either elicit a facial expression or change the rate of sucking. **Taste preferences change overtime Newborns can distinguish between their mother’s smell from other women as early as 3 days. 7.2.3 - Vestibular Sensitivity Vestibular sensitivity : The perceptual experience that results from motion of the body and the pull of gravity. The posture can alter alertness in babies (more alert in vertical than horizontal position). Development of vestibular sensitivity and posture is necessary for the development of motor skills.  As the wall moves towards the infant, the visual system signals movement, while the vestibular system does not; the infant falls backward indicating dominance of visual cues. **Visual cues can outweigh vestibular cues. 7.3 - HEARING 7.3.1 - Prenatal Hearing As early as the 25th week, the fetus shows sound reception. By 28 weeks the fetus shows reactivity to sound, including their mother’s voice (sucking rate changes). 7.3.2 - Sensitivity to Sound Newborns are better at hearing low frequencies than higher frequencies ; also soothed by low frequency sound. Infants prefer sounds that fall within the frequency range of the human voice. 7.3.3 - Discriminating Sounds After birth, newborns can discriminate between… mother’s (but not their father’s) voice from that of strangers; familiar stories from new stories; languages. 7.3.4 - Sound Localisation Newborns can distinguish the location of where the sound is coming from. To accomplish sound localisation, babies must be able to recalibrate or readjust. 7.4 - VISION 7.4.1 - Sensory Capabilities Babies are responsive to fluctuations in light intensity and movement. Preference method : Method for the study of visual ability in infancy. Two stimuli are presented simultaneously, and the amount of time the infant looks at each is measured. Visual acuity : The clarity in which a visual image is perceived. To measure visual acuity, we show a baby a grey picture next to a second picture that contains black and white stripes. As the stripes get more narrow and compressed, the baby has more difficulty distinguishing them from the grey picture. For a newborn it ranges between 20/400 to 20/800. Visual accommodation : The automatic adjustment of the lens of the eye to produce a focus image of an object. The neural circuits that govern this accommodation do not function in a newborn. The colour vision is present, but not fully developed in newborns. It improves by 3-4 months because of the maturation of colour receptors cells.  7.4.2 - Visual Relations Between 1-3 months of age, infants begin to organize visual stimuli together rather than only the details. 7.4.3 - Face Perception Babies show an interest in face or face-like stimuli from birth. Young infants’ processing of faces is limited; they tend to look near the high-contrast border of the face, and they pay little attention to interior detail. 7.4.4 - Objects and Their Properties 1) Consistencies Size constancy : The physical size of an object remains the same, even though the size of its projected image on the eye varies. Shape constancy : The physical shape of an object remains the same, even though the size of its projected image on the eye varies. Brightness constancy : The brightness of an object remains the same, even though the amount of light it reflects back to the eye changes. Colour constancy : The colour of an object remains the same, even though the wavelengths it reflects back to the eye changes. 2) Continuity The concept that we see objects as continuous and whole, even when our view is partially blocked. 7.4.5 - The Spatial Layout Infants are able to perceive depth by 7 months (when they start to crawl). Visual cliff experiment : The infant is placed on a glass-covered table near an apparent drop-off, and perception of death is inferred if the infant avoids the drop. Optical flow : The sensation that objects are apparently moving as a result of self-produced movement. Some depth and distance cues include : Pictorial cues : Cues that indicate the relative distances of objects through static, picture-like information (ex. convergence, relative size and interposition). **3 month old babies perceive these types of cues Kinetic cues : Cues that indicate the relative distance of objects through movement of the objects or of the observer (ex. motion parallax : objects that are closer to us show greater apparent movement than objects that are further away). **1-3 month old babies perceive these types of cues 7.5 - INTERMODAL PERCEPTION This perception refers to the ability to realize that cues from different senses go together. 7.5.1 - Exploratory Intermodal Relations Infants’ inborn ability to relate different sensory modes. These relations between sensory modalities are biological predispositions refined by experience.  7.5.2 - Intermodal Representation Infants’ ability to develop mental r