ECC Chapter 2 PSY 218 Spring 2015.pptx

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Nature with Nurture

• _{When the human genome was mapped, it presented something}

similar to an instruction manual for humans.

• _{Changed the goal of research towards focusing which genes}

influence which characteristics.

• Leads to an increased understanding of development.

• _No_complex_{human trait is determined solely by a single}_{or multiple genes.}

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Perspectives on Nature and Nurture

• _{In studying the role of genes and the environment in development,}

there are generally four main views:

• _{1. Development is driven by nature.} • _{2. Development is driven by nurture.}

• _{3. Development is part nature, part nurture.}

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Development is Driven by Nature

• _{The idea that characteristics are innate is known as Nativism.}

• _{Preformationism – 17}

th

_{century idea that embryos are preformed.}

They are essentially miniature adults with determined anatomy and

behavior.

• _{For example, concept of “original sin” indicating that people are innately bad.}

• _{Genetic Determinism – Human qualities are genetically determined}

and unable to be altered by nature.

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Eugenics

• The general idea that through selective breeding, we could eliminate undesirable qualities while promoting more desirable traits in individuals.

• Many people supported this movement at the time.

• Led to significant problems:

• _Racism

• Forced colonization

• Sterilization.

• Still influences our educational system through IQ testing.

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Development is Driven by Nurture

• _{Environmentalists – View an individual’s characteristics as entirely the}

product of experience

• _{Viewed infant’s minds as being a tabula rasa, or blank slate, and that they} develop as a result of experience.

• _{Led to a change in the view that insanity is a result of evil possession and is,} instead, a possibly treatable illness.

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Development is Part Nature, Part

Nurture

• _{In the late 20}

th

_{century, scientists became dissatisfied with nativism}

and environmentalism.

• _{Decided to try to incorporate both views.}

• _Heritability

• _{Researchers began determining how different traits are influenced by genetic} factors.

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Development is Part Nature, Part

Nurture

• Adoption studies became prominent to determine similarities between

biological parents/children and adoptive parents/children.

• _{Family relatedness studies use blended families where children with}

different degrees of biological relatedness are raised in the same

environment to establish differences/similarities.

• _{These types of studies have shown that most human traits have some}

sort of heritable component.

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Development is Part Nature, Part

Nurture

• _{Three major criticisms of heritability studies:}

• _{1. Genetic and environmental influences work hand in hand.}

• _{2. The impact of genes may vary depending on the quality of the} environment.

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Development Results from the

Interplay of Nature and Nurture

• _{Most contemporary view of development.}

• _{Emphasizes the interaction of nature and nurture.}

• _{Often based in the works of Darwin and the theory of evolution.}

• _{Survival of the fittest} • _{Natural selection}

• _{Organisms that are “fittest” and have adapted are the most likely to survive} and pass on their characteristics. What is adaptable depends on the

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Evolution of Emotions

• _{Many theorists believe that emotion may have some developmental}

or evolutionary properties.

• _{For example, people across cultures experience 6 basic emotions:}

• _{Anger – A good motivator, generally caused by violated expectations.}

• _{Fear – Provides us with decision making skills that eliminate unnecessary risk.} • _{Disgust – Keeps us from eating spoiled/poisonous foods.}

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Development Results from the

Interplay of Nature and Nurture

• _{Most developmental scientists ascribe to the idea of Epigenesis.}

• _{Believe that development is a gradual process made complex due to the} interaction between heredity and the environment.

• _{View very little as being pre-determined.}

• _{Helped lead to the idea of stem cells as a source of developmental}

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Why can’t we have just one theory?

• Why not just pick the best theory and throw away the rest?

• _{Who determines what is the best?}

• _{For example, schools:}

• _{Some approaches may believe that only hard sciences should be taught in schools.} • _{Other approaches believe that only creative abilities should be taught.}

• Still others view that education should be a more rounded approach and find a middle ground.

• _{Which is the “correct” way to teach children that leads to them having}

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Becoming Human

• _{The study of genetics focuses on how gens make humans distinct from}

other species, as well as from each other.

• _{For example, Bipedalism (walking on two legs) is a human trait that}

results from natural selection.

• Frees up hands for key survival tasks.

• _{Some human behavior and development is dictated by our genetics.}

• _{This is called Canalization}

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Becoming Human

• _{One particular human feature is that we are born “prematurely”,}

meaning are unable to take care of ourselves and have prolonged

immature appearance and behavior for many years.

• _{We aren’t born as “small adults” like some species.}

• This may be due to our importance on socialization and prolonged immaturity promotes social attachment.

• _{Humans are also predisposed to learning and are better than most}

species at changing behavior when necessary.

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Human Diversity

• _{Human bodies are composed of trillions of cells which contain a}

nucleus with 23 pairs of chromosomes.

• _{One pair from each parent.}

• _{Chromosomes are strings of DNA containing the instructions for the} development of a human being.

• DNA is composed of four chemical basis.

• _Adenine • Thiamine

• Guanine

• Cytosine.

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Human Diversity

• _{A segment of a chromosome that determines what types of proteins}

are created by our bodies are known as genes.

• _{3,000 base pairs in length.}

• _{The 23 pairs of chromosomes we inherit from our parents is called}

our genotype.

• _{This is the biochemical information that is unique to you.}

• _{Our observable characteristics are known as our phenotype.}

• _{Often depends on experience and environment}

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Human Diversity

• _{Genetic information is passed on between cells during mitosis and}

meiosis.

• _{Mitosis – a cell divides and makes two identical copies of itself}

• _{Occurs throughout your body during development and adulthood.} • _{New tissue growth, wound healing, etc.}

• _{Genetic information is copied without changes.}

• _{Meiosis – a reproductive cell divides and makes two gametes}

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Human Diversity

• _{During meiosis “crossing over” shuffles the genes found on each}

chromosome.

• _{Each gamete has a unique combination of alleles not found in the parental cell.}

• Allele = a copy (version) of a particular gene.

• _{Example: a gene for eye color may have multiple alleles (brown, blue).}

• _{During fertilization gametes combine.}

• _{Each gamete has 23 chromosomes, one copy of every gene.}

• When egg + sperm combine, the daughter cell will have 46 chromosomes.

• _{One copy of each chromosome was inherited from the father, and one copy}

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Human Diversity

• _{Additive heredity}

• _{You have two different alleles for each gene (maternal, paternal).} • _{The combination of effects from both alleles produces new traits.}

• _{Example: A tall man and a short woman may produce offspring of medium} height.

• _{Dominant/recessive heredity}

• _{One allele overrides another allele, completely masking it.}

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Human Diversity

• Incomplete dominance

• One allele mostly overrides another allele.

• _{Example: A child with one brown eye allele and one green eye allele will have} hazel eyes. The brown eye allele is expressed more strongly, but some of the green eye allele is still expressed, causing a mixed phenotype.

• _{Regulator genes}

• _{Genes that do not produce a trait themselves, but control when other genes are} turned on/off.

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Human Diversity

• _{Genes are influenced by the environment.}

• _{You may have the same allele for a trait as another person, but the}

environment can affect how the trait is expressed.

• _{Example: 5-HTT is a gene that controls serotonin levels. One allele of}

5-HTT is shorter and causes low serotonin as a result. Individuals with

the short allele are more prone to depression after experiencing

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The Importance of Context

• _{The Ecological Perspective on Development}

• _{A child is “nested” within the immediate context of who they interact with.}

• Which is nested within the community

• Which is nested within the region.

• Etc..

• _Microsystems

• _{A setting in which a child interacts with others face-to-face every day.}

• Influences development in a bidirectional fashion.

• E.g., children influence teachers who then influence the child.

• Microsystem relationships are also multifaceted.

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The Importance of Context

• _Mesosystem

• _{The ways in which the microsystems are connected.}

• 2 types of connections:

• 1. Events in one setting may affect behavior of another setting.

• 2. Characteristics in one microsystem may either conflict with or reinforce the experiences in another microsystem.

• _Exosystem

• _{The contexts outside the child’s immediate, everyday experiences.}

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The Importance of Context

• _Macrosystem

• _{The “outer layer” that includes larger forces that define society at a given} point in time.

• Such as cultural values, political and economic conditions, major historical events, etc…)

• _{All of these systems must be considered when understanding}

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The Interplay between Genes and

Context

• Context plays an important role in gene expression and ultimately development.

• Under one set of a different set of conditions you conditions, the combination of eggs, milk, and flavoring leads to custard.

• Under a different set of conditions/context you can end up with a curdled mess (heating milk too high, etc…)

• _{How a person’s genotype becomes a phenotype depends on}

gene-environment interaction.

• Same as above – inherited traits lead to different characteristics in different contexts.

• For instance, there is no gene for a specific height, rather we inherit a range of possibilities.

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Gene-Environment Correlations

• _{Passive Gene-Environment Correlations}

• Results from the parent providing both the genes and the environment for the child.

• “Passive” in the sense that the child does not have to do anything, these are all passed down to the child.

• _{E.G. Children who grow up in intellectually stimulating environments probably have intelligent}

parents (who passed along their genetic intelligence).

• _{Evocative Gene-Environment Correlations}

• _{Result from the fact that genotypically different individuals elicit different responses}

from their environment.

• “Evocative” in the sense that the child evokes a response from others based on how they behave.

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Gene-Environmental Correlations

• Active Gene-Environment Correlations

• _{Occur because children select contexts that they find stimulating and rewarding.} • Also called “niche picking”.

• _{Children choose to participate in contexts that tend to strengthen the traits that} led them to select those contexts.