CHAPTER 3
FAMILY STUDIES: persons who live in the same household are compared to see how similar they are on one or more attributes. If the attribute in question is heritable, then the similarity between any two pairs of individuals who live in the same environment should increase as a function of their KINSHIP ( the extent to which they have the same genes) Identical twins have: kinship 100% or 1.0 Fraternal twins average: kinship 50% or .5
2 kinds of family studies: 1. TWIN DESIGN (TWIN STUDY): a study in which sets of twins that differ in zygosity (kinship) are compared to determine the heritability of an attribute. (Are identical twins reared together more similar to each other on various attributes than pairs of fraternal twins reared together?) Identical twins should be similar for they have 100% genes in common and fraternal twins on average share only 50 %. 2. ADOPTION DESIGN: a study in which adoptees are compared with their biological relatives and their adoptive relatives to estimate the heritability of an attribute. (Are adopted children similar to their biological parents, whose genes they share or are they similar to their adoptive parents, whose environment they share?)
Contributions of 3 factors to individual differences in IQ: 1. GENE INFLUENCES: How strong is the hereditary influence? Behavioral geneticists use statistical techniques to estimate the amount of variation in a train that is attributable to hereditary factors. This index, called a HERITABILITY COEFFICIENT. H=(r identical twins - r fraternal twins) X2 Heritability of an attribute equals the correlation between identical twins minus the correlation between fraternal twins, all multiplied by a factor of 2.
2. NONSHARED ENVIRONMENTAL INFLUENCES (NSE): These are experiences that are unique to the individual - experiences that are NOT shared by other members of the family and thus make family members DIFFERENT from each other. Because identical twins share the same genes and family environment, any differences between twins raised together must necessarily be due to differences in their experiences. Because the only factor that can make identical twins raised together any different from one another are experiences they do not share, we can estimate the influence of nonshared environmental influences by the following formula: NSE = 1-r(identical twins reared together.
BEHAVIORAL GENETICS: the scientific study of how genotype interacts with environment to determine behavioral attributes such as intelligence, personality and mental health.
GENOTYPE: the genetic endowment that an individual inherits. PHENOTYPE: the ways in which a person's genotype is expressed in observable or measurable characteristics.
When studying traits that a person either does or does not display...researchers calculate and compare CONCORDANCE RATES. CONCORDANCE RATES ARE: the percentage of cases in which a particular attribute is present for one member of a twin pair if it is present for the other.
HERITABILITY COEFFICIENT: A numerical estimate, ranging from .00 to +1.00, of the amount of variation in an attribute that is due to hereditary factors.
NATURAL SELECTION: an evolutionary process, proposed by Charles Darwin, stating that individuals with characteristics that promote adaptation to the environment will survive, reproduce, and pass these adaptive characteristics to offspring; those lacking these adaptive characteristics will eventually die out. Over many generations the genes underlying the most adaptive behaviors would become more widespread in the species, characterizing nearly all individuals.
JOHN BOWLBY believed that children display a wide variety of PREPROGRAMMED BEHAVIORS and each of these responses promotes a particular kind of experience that will help the individual to survive and develop normally. ie: infants are said to be biologically programmed to cry as a distress signal. And parents are biologically predisposed to respond to such signals.
According to LORENZ AND TINBERGEN...members of all animal species are born with a number of biologically programmed behaviors that are: 1. products of evolution and 2. adaptive in that they contribute to survival. ie: birds follow their mothers, build nests and sing songs.
These biologically programmed characteristics are thought to have evolved as a result of the Darwinian process of natural selection
Last 2 recent perspectives on human development: 1. Vygotsky's sociocultural theory 2. Social information-processing approach
VYGOTSKY'S SOCIOCULTURAL THEORY: Vygotsky's perspective on development, in which children acquire their culture's values, beliefs, and problem-solving strategies through collaborative dialogues with more knowledgeable members of society. He believes that: 1. human development occurs in a particular sociocultural context that influences the form that it takes. 2. many of a child's most noteworthy personal characteristics adn cognitive skills evolve from social interactions with parents, teachers, and other more competent associates.
IN SUM: Vygotsky believed that neither the course or the content of intellectual growth was as "universal" as Piaget had assumed.
Vygotsky agreed with Piaget that children are curious explorers who are actively involved in learning adn discovering new principles
Ethologists believe that an individual's early learning experiences are very important. There may be "critical period" for the development of many attributes adn behaviors. A CRITICAL PERIOD is a short period of the life cycle during which the developing organism is uniquely sensitive or responsive to specific environmental influences. Outside this period, the same environmental events or influences are thought to have no lasting effects.
With humans we use the words SENSITIVE PERIOD: the period of time that is optimal for the development of particular capacities or behaviors, and in which the individual is particularly sensitive to environmental influences that would foster these attributes.
Modern evolutionary theorists contend that the largely unconscious purpose of protecting and maximizing the number of genes we leave to posterity can explain sex differences in mating preferences.
Compared to other animal species, human beings develop very slowly, remaining immature adn requiring others' nurturance and protection for many years. Modern evolutionary theorists view this long period of immaturity as a necessary evolutionary adaptation.
ANOTHER EVOLUTIONARY VIEWPOINT: ALTRUISM: a selfless concern for the welfare of others that is expressed through prosocial acts such as sharing, cooperating, comforting others, or helping.
Criticisms of evolutionary theory: very hard to test. (Just so stories...an explanation that sounds plausible and in fact may be true but is not supported by any conclusive evidence. They are also impossible to falsify!) Evolutionary theorists are also criticized as being RETROSPECTIVE: EXPLAINING WHAT HAS ALREADY HAPPENED BUT NOT WHAT WILL LIKELY HAPPEN IN THE FUTURE.
Behavioral geneticists claim that most behavioral attributes are the end product of a long and involved interplay between hereditary predispositions and environmental influences. Even attributes such as physical stature that seem to have a very strong hereditary component are often modified in important ways by environmental influences.
DIFFERENCE BETWEEN ETHOLOGISTS AND MODERN EVOLUTIONARY THEORISTS AND BEHAVIORAL GENETICISTS: evolutionary viewpoints study inherited attributes that characterize ALL members of a species. behavioral geneticists focus on the biological bases for VARIATION among members of a species. Behavioral geneticists seek to learn what makes us DIFFERENT from one another.
CONTEXTUAL MODEL: VIEW OF CHILDREN AS ACTIVE ENTITIES WHOSE DEVELOPMENTAL PATHS REPRESENT A CONTINUOUS, DYNAMIC INTERPLAY BETWEEN INTERNAL FORCES (NATURE) AND EXTERNAL INFLUENCES (NURTURE)
Development is not piecemeal but HOLISTIC - humans are biological, cognitive, and social creatures and each of these components of "self" depends in part on changes that are taking place in other areas of development.
Today's developments largely reject Arnold Geusell...but many till believe that biological influences play a significant role in human development......especially in ETHOLOGY.
ETHOLOGY can be traced back to Charles Darwin....and modern ethology arose from work of Konrad Lorenz and Niko Tinbergen....European zoologists.
VYGOTSKY believed infants are born with a few elementary mental functions - attention, sensation, perception, and memory - that are eventually transformed by the culture into new and more sophisticated mental processes that he called HIGHER MENTAL FUNCTIONS.
Each culture provides its children TOOLS OF INTELLECTUAL ADAPTATION that permit them to use their basic mental functions more adaptively. TOOLS OF INTELLECTUAL ADAPTATION: B Vygotsky's term for methods of thinking and problem-solving strategies that children internalize from their interactions with more competent members of society.
CHRONOSYSTEM: in ecological systems theory, changes in the individual or the environment that occur over time and influence the direction development takes.
Ecological theorists don't believe in using the laboratory contexts. They argue that by observing transactions between developing persons and their ever changing NATURAL settings will we ever understand how individuals influence and are influenced by their environments.
Proponents of evolutionary perspectives have already contributed importantly to our discipline by reminding us that every child is a biological creature who comes equipped with a number of adaptive, genetically programmed characteristics.
Ethological notion: Infants are inherently sociable creatures who are quite capable of promoting and sustaining social interactions form the day they are born. This viewpoint differs from that of behaviorists who portray the newborn as a tabula rasa.
SOCIAL INFORMATION PROCESSING THEORY: social-cognitive theory stating that the explanations we construct for social experiences largely determine how we react to those experiences. THESE THEORISTS DEPICT HUMAN BEINGS AS ACTIVE PROCESSORS OF SOCIAL INFO WHO ARE CONSTANTLY GENERATING EXPLANATIONS OR CAUSAL ATTRIBUTIONS.
CAUSAL ATTRIBUTIONS: conclusions drawn about the underlying causes or our own or another person's behavior. These theorists propose that children's impressions of themselves, other people and their social experiences will change, becoming much deeper adn more abstract as they become better at inferring the reasons that people behave as they do. BUT unlike Piaget... these theorists view the course as a continuous, incremental process that is NOT at all stagelike.
ETHOLOGY: the study of the bioevolutionary bases of behavior and development.
ARNOLD GEUSELL: believed was that children development is largely a matter of biological maturation. How parents raised their kids was of little importance.
EMPATHIC CONCERN: a measure of the extent to which an individual recognizes the needs of others and is concerned about their welfare. The capacity for empathy may be innate and there are biological bases for INDIVIDUAL differences in empathic concern. Identical twins who have been living apart for many years still resemble each other on measures of empathic concern whereas fraternal twins not so much.
Aspects of the home environment that all family members share don't contribute much to the development of personality.
Vygotsky believed that important discoveries that children make occur within the context of cooperative dialogues between a skillful tutor who models the activity and gives verbal instructions and a pupil who seeks to understand the tutor's instruction and internalizes this info.
COLLABORATIVE LEARNING: The process of learning or acquiring new skills that occurs as novices participate in activities under the guidance of a more skillful tutor.
TRAITS: a dispositional characteristic that is stable over time ndn across situations.
Attribution theorists argue that to view someone as exhibiting a train, the perceiver must first: 1. judge the actor's behavior to be internally caused, rather than attribute it to situational constraints, and then: 2. inver that this internal cause in reasonably stable over time and across situation.
Some anti evolutionary theorists believe that cultural learning experiences quickly overshadow innate evolutionary mechanisms in shaping human conduct and character.
Beginning another viewpoint! Theory #2....BEHAVIORAL GENETICS: BIOLOGICAL BASES FOR INDIVIDUAL DIFFERENCES. THEORISTS HAVE ASKED THE QUESTION - Are there specific abilities, traits, and patterns of behavior that depend very heavily on the particular combination of genes that an individual inherits, and if so, are these attributes likely to be modified by one's experiences? Those that believe this way are BEHAVIORAL GENETICISTS....
It may be possible to prevent the onset of most genetically influenced disorders if we 1. learn about the environmental triggers that precipitate these disturbances 2. strive to develop interventions or therapeutic techniques that will help high risk individuals to maintain their emotional stability in the face of environmental stress.
Behavioral geneticists believe that our genes may actually influence the kinds of environments we are likely to experience in 3 ways: 1. Passive genotype/Environmental Correlations: The notion that the rearing environments that biological parents provide are influenced by the parent's own genes and hence are correlated with the child's own genotype. ie: children of athletic parents may come to enjoy athletic pursuits for BOTH hereditary adn environmental reasons, and the influences of heredity and environment are tightly intertwined. 2. EVOCATIVE GENOTYPE/ENVIRONMENT CORRELATIONS: the notion that our heritable attributes affect other's behavior toward us and thus influence the social environment in which development takes place. Reactions of other people to the child are environmental influences that play an important role in shaping that child'e personality. 3. ACTIVE GENOTYPE/ENVIRONMENT CORRELATIONS: the notion that our genotypes affect the types of environments that we prefer and seek out. ENVIRONMENTS CHILDREN PREFER AND SEEK OUT WILL BE THOSE THAT ARE MOST COMPATIBLE WITH THEIR GENETIC PREDISPOSITIONS. Virtually ALL siblings other than identical twins should become much less similar over time as they emerge from the relatively similar rearing environments parents impose during the early years. But with identical twins - even if raised apart should be similar in some respects if their their identical genes cause them to seek out and to prefer similar activities adn experiences.
Theory #3 ECOLOGICAL SYSTEMS THEORY: Urie Bronfenbrenner's Ecological Systems Theory: model emphasizing that the developing person is embedded in a series of environmental systems that interact with one another and with the person to influence development....also called BIOECOLOGICAL THEORY. BRONFENBRENNER SAYS: the developing person is said to be at the center of and embedded in several environmental systems, ranging from immediate settings such as family to more remote contexts such as the broader culture. Each of these systems interacts with the others and with the individual to influence development in important ways.
Bronfenbrenner's contexts for Development: 1: MICROSYSTEM: the immediate settings that the person actually encounters; the innermost of his environmental layers, or contexts. (family, day care, preschool, youth groups etc; each person influences and is influenced by all other persons in the system) 2: MESOSYSTEM: the interconnections among an individual's immediate settings, or microsystems. The second of Bronfenbrenner's environmental layers, or contexts. (connections among homes, schools and peer groups.) 3: EXOSYSTEM: social systems that children and adolescents do not directly experience but that may nonetheless influence their development; 4. MACROSYSTEM: the larger cultural or subcultural context in which development occurs;
Theorizing about attributional processes can be traced to Fritz Heider.....
IN SUM....social information-processing theorists contend that the implications of our experiences for our social conduct and personality development depend not so much on what these experiences are a on the attributions we make about them.
SEPARATED IDENTICAL TWINS: Separated identical twins can be different and yet so similar because of ACTIVE GENE INFLUENCES.
IN SUM: Scarr and McCartney believe that : 1. People with different genotypes are likely to evoke different responses from others and to select different environmental niches for themselves. 2. The responses they evoke and the niches they select depend to no small extent on the particular individuals, settings, and circumstances they encounter. genotypes and environments interact to produce developmental change and variations in developmental outcomes.
CONSISTENCY SCHEMA: attributional heuristic implying that actions that a person consistently performs are likely to be internally caused.
IN SUM: Younger children do not think about traits in teh same ways that older ones do. They believe that many traits will change, becoming more positive with age.
The time frame for sensitive periods are less rigid than those of critical periods. It is possible for development to occur outside of a sensitive period but then it is much more difficult to foster.
IN SUM: ethologists clearly acknowledge that we are heavily influenced by our experiences. Yet they are quick to remind us that we are inherently biological creatures whose inborn characteristics affect the kinds of learning experiences we are likely to have.
PRIVATE SPEECH: Vygotsky's term for the subset of a child's verbal utterances that serve a self-communicative function and guide the child's activities.
INNER SPEECH: internalized private speech; covert verbal thought.Vygotsky believes that children's mind, skills, and personalities develop as they: 1. take part in cooperative dialogues with skilled partners on tasks that are within their Zone of Proximal development and 2.incorporate what skillful tutors say to them into what they say to themselves.
3. SHARED ENVIRONMENTAL INFLUENCES (SE): an environmental influence that people living together share and that should make these individuals SIMILAR to one another. SE = 1 - (H + NSE) SHARED ENVIRONMENTAL INFLUENCES ON A TRAIT EQUAL 1 (the total variation for that trait_ minus the variation attributable to genes (H) and nonshared environmental influences (NSE).
INTROVERSION/EXTROVERSION: the opposite poles of a personality dimension: introverts are shy and anxious around others, adn tend to withdraw from social situations; extroverts are highly sociable adn enjoy being with others. Introversion/extroversion shows about the same moderate level of heritability as IQ does.
Theories and worldviews: MECHANISTIC MODEL: VIEW OF CHILDREN AS PASSIVE ENTITIES WHOSE DEVELOPMENTAL PATHS ARE PRIMARILY DETERMINED BY EXTERNAL (ENVIRONMENTAL) INFLUENCES.
ORGANISMIC MODEL: VIEW OF CHILDREN AS ACTIVE ENTITIES WHOSE DEVELOPMENTAL PATHS ARE PRIMARILY DETERMINED BY FORCES FROM WITHIN THEMSELVES.
SCHIZOPHRENIA: a serious form of mental illness characterized by disturbances in logical thinking, emotional expression, and interpersonal behavior.
PEOPLE DO NOT INHERIT BEHAVIORAL DISORDERS; INSTEAD THEY INHERIT THE PREDISPOSITIONS TO DEVELOP CERTAIN ILLNESSES OR DEVIANT PATTERNS OF BEHAVIOR. Even when a child's family history suggests that such a genetic predisposition may exist, it usually takes one or more very stressful experiences to trigger a disorder.n
ZONE OF PROXIMAL DEVELOPMENT: Vygotsky's term for the range of tasks that are too complex to be mastered alone but can be accomplished with guidance and encouragement from a more skillful partner.
SCAFFOLDING: process by which an expert, when instructing a novice, responds contingently to the novice's behavior in a learning situation so that the novice gradually increases his or her understanding of a problem.
HERITABILITY: the amount of variability in a trait that is attributable to hereditary factors.
SELECTIVE BREEDING EXPERIMENT: a method of studying genetic influences by determining whether traits can be bred in animals through selective mating.
METHODS OF STUDYING HEREDITARY INFLUENCES: 1. SELECTIVE BREEDING 2. FAMILY STUDIES
SELECTIVE BREEDING: (RAT MAZE EXPERIMENT) "maze-bright and "maze-dull" rats.
Behavioral geneticists David Rowe adn Robert Plomin said: The aspects of environment that contribute most heavily to personality are NONSHARED ENVIRONMENTAL INFLUENCES...influences that make individuals DIFFERENT from each other. To the extent that siblings are NOT treated aloke by parents, they will experience different environments which will increase the likelihood that their personalities will differ.
SUM: the family environment DOES contribute importantly to personality, but not simply because it has a standard effect on all family members that makes them alike. When it comes to the shaping of many other basic personality traits, it is the NONSHARED experiences people have - in concert with genetic influences - that contribute most to their phenotypes.
Theory #1.......Another movement know as MODERN EVOLUTIONARY THEORY are also interested in specifying how natural selection might predispose us to develop adaptive traits, motives and behaviors....except that evolutionary theorists make different assumptions about the workings of evolution than ethologists do.
The ethological notion that preselected adaptive behaviors are those that ensure survival of the INDIVIDUAL. Modern evolutionary theorists argue that preselected, adaptive motives and behaviors are those that ensure the survival and spread of the INDIVIDUAL'S GENES!
HOLISTIC PERSPECTIVE: a unified view of the developmental process that emphasizes the interrelationships among the physical/biological, mental, social, and emotional aspects of human development.
The holistic perspective is the dominant theme of human development.
As social speech is translated into private speech and ultimately into inner speech the culture's preferred methods of thinking and problem solving work their way from the language of competent tutors into the child's own thinking.
VYGOTSKY HAS PROVIDED A VALUABLE SERVICE BY REMINDING US THAT BOTH COGNITIVE GROWTH AND SOCIAL DEVELOPMENT ARE: 1. MUCH LESS UNIVERSAL THAN SOME THEORISTS CONTEND AND 2. ARE BEST UNDERSTOOD WHEN STUDIED IN THE CULTURAL AND SOCIAL CONTEXTS IN WHICH THEY OCCUR.
