PSY 1003: Lecture 4: Nature, Nurture, & Human Diversity

Genes

the biochemical units of heredity that make up the chromosome; small segments of DNA capable of synthesizing proteins

• humans have around 20,000

• can be active (provide code for our body’s building blocks: proteins) or inactive

Chromosomes

threadlike structures made of DNA molecules that contain the genes

• humans have 46 (23 matching pairs), each from one biological parent and the other half from the other biological parent

Cells

where chromosomes are housed within the nuclei

• many different types (i.e. skin, blood, nerve, etc.)

Genetic Expression

process by which proteins are made based off of the “instructions” provided by genes

• When encoded information in a gene is turned into a kind of function (i.e., environmental factors can influence which genes are expressed)

Identical (Monozygotic) Twins

individuals who developed from a single fertilized egg that split in two, genetically identical organisms

Fraternal (Dizygotic) Twins

individuals who developed from separate fertilized eggs; they are genetically no closer than siblings, but they shared a prenatal environment

Studying Genetics Identical vs. Fraternal Twins

Identical Twins

• share more similarities in physical attributes, personality, interests, fears, etc. compared to fraternal twins

• environment still plays a role, e.g. having access to better nutrition or speech therapy led to different outcomes for the sets twins

Studying Genetics Outside of Identical Twins

• Individuals who are raised together in the same environment do not resemble each other in personality (even biological siblings)

• Adopted— personality traits like extroversion or agreeableness have been found to be more closely aligned with their biological parents

• Study with macaque monkeys showed that babies raised by foster mothers still showed social behavior that was more similar to their biological mothers

Epigenetics

“in addition to” or “above” the genetics; tell us about how the environment influences our genome and our genetic expression

• not fixed traits—can change

• trauma, exposure to toxins, etc. can all influence us

Evolutionary Psychology

the study of evolution of behavior and the mind, using principles of natural selection

Natural Selection

the principle that inherited traits that better enable an organism to survive and reproduce in a particular environment (in competition with other trait variation) most likely be passed on to succeeding generations

• varied offspring compete for survival

• various biological and behavioral variation increase survival changes for organisms

• the offspring that survive are more likely to pass their genetics to following generations

• over time, characteristics of a population change

Mutation

a random error in gene replication that leads to a change

Humanity’s Genetic Legacy

• humanity shares a common genetic profile

• across cultures we tend to share certain predispositions—research tends to show that when faced with certain moral dilemmas people will opt for responses that ensure the survival of more people

• there are ways that our previous evolutionary makeup has prepared us for aspects of life that are not necessarily part of our current experiences

Evolutionary Explanations for Sexuality (Theory)

• women tend to be choosier than men when it comes to picking a sexual partner-related to ensuring survival of offspring; whereas men would tend to be more likely to have more sexual partners to create more offspring

• women prefer partners who are more likely to be loyal and have social or other resources, whereas men prefer partners who show signs of potential future fertility

Critiques of the Evolutionary Perspective

• natural selection plays a role in helping with survival and reproduction

• may be social consequence for conclusions drawn by evolutionary psychology research (i.e., consequences for social movements to reduce aggression)

• some behaviors are not easily explained by evolutionary perspective

• still has limitations

Social scripts

a culturally modeled guide for how to act

Experience Influences Development

• biological and environmental interact with one another to influence brain development

  Example: a research study showed that rats raised in an environment with more enrichment showed more cerebral cortex than rats in an environment without enrichment

• nature and nurture influence our synaptic connections

• various experiences strengthen these synaptic connections—sensations, movement, activity, etc.; if other pathways are not used, they become weaker (i.e., a trail that is not used)

• by puberty, synaptic pruning causes a significant loss of connections that are not used

• important to remember that brain development does not end in childhood

• neuroplasticity allows our brains to change and reorganize in response to our experiences

Influences of Parents and Peers

• parenting can influence development, but we tend to see more intense influences when children are exposed to extremes (i.e., abuse)

• parents and family environment can have an impact on academics, vocation, political affiliation, and religiosity

• there is a significant amount of peer influence during our childhood and adolescent years as we attempt to connect socially with others

Norms

certain rules or behaviors that are expected and followed in a given environment (i.e., gender norms)

Culture

the enduring behaviors, ideas, attitudes, values, and traditions shared by a group of people and transmitted from one generation to the next

Tight Culture

places with clearly defined and reliably imposed norms

Loose Culture

places with flexible and informal

Cultural & Self (Individualism vs. Collectivism)

• various cultures (in different places) are going to view this differently

• informs our human functioning

Gender Identity

how you think about yourself

Gender Expression

how you demonstrate your gender

Biological Sex

organs, hormones and chromosomes

Sexual Orientation

physical, spiritual and emotional attraction

X Chromosome

sex chromosomes found in both males and females; two X chromosomes are present in females and one X chromosome is present in males

Y Chromosome

sex chromosome that is typically found in only males; an X chromosome paired with a Y chromosome leads to the production of a male child

Testosterone

the most predominant male sex hormone (found in both males and females); contributes to development of male sex organs during fetal development, and during adolescent development, it contributes to male sex characteristics

Estrogen

sex hormones that are secreted in larger amounts in females compared to males; contributes to female sex characteristics

Intersex

a term that is used to describe someone with a combination of male and female sex characteristics

• individuals with sexual development differences have faced significant oppression over the years

• in recent years, California has dictated that surgeries or procedures to assign a particular sex to such individuals are not to be done until that person is able to give consent

Role

expectations that are put in place regarding how people in certain social positions should interact and behave

Gender Role

expectations regarding the attitudes and behaviors that are exhibited by different genders

Sexual Aggression

any physical or verbal behavior of a sexual nature that is unwanted or intended to harm someone physically or emotionally; can be expressed as either sexual harassment or sexual assault

Cisgender

when a person’s gender identity parallels to their assigned sex

Transgender

when a person’s gender identity differs from their assigned sex

Non-binary

a person who does not identify with a specific binary gender

• evidence that dates back to ancient times and civilization that shows the existence of gender-expansive individuals

Social Learning Theory

a theory that describes the process of learning certain behaviors through observation of the environment

Gender Typing

when a person acquires a role that is specifically mirroring traditional masculine or feminine gender roles

Androgyny

a mixture of traditionally feminine and masculine characteristics

The Biopsychosocial Approach

1. Biological Influences

2. Psychological Influences

3. Social-cultural influences

   • all contribute to individual development