Intro to Psych: Genes, Epigenetics, and the Environment

Nurture

suggests that a person’s growth is determined by their upbringing, education, and culture rather than inherent biological factors (resonates with philosophical empiricism)

Nature

suggests that our genetic makeup and inherited traits from our parents determine our growth (resonates with nativism)

Myths about the Human Mind

• heritable traits cannot be changed (genes are not fate)

• raising children similarly results in similar adult personalities (similarity is also based on genes)

The nature versus nurture debate is a way of thinking about the origins of human behavior that keeps us from understanding the origin of human behavior? Why is this so?

Due to the complex interactions in humans, they are interwined, its not as either/or choice

Genes 

the major units of hereditary transmission

Degree of Relatedness

the probability that individuals share genes

• helps to reveal the importance of environmental and genetic influences

Heritability

a measure of the variability of a trait among individuals that can be accounted for by genetic influences

• 0=genes do not contribute to individual differences

• 1=indicates that genes are the only cause of individual differences

Chromosomes

large strands of genes/DNA

RNA

protein molecules produced by the the DNA in our chromosomes

• communicates a copy of the DNA code to cells that produce proteins

Monozygotic (identical twins)

the most genetically related people, share 100% of the same DNA

Dizygotic (faternal twins)

share 50% of the same DNA, the same as a normal pair of siblings

Epigenetics

explores how the environment determines gene expression

Epigenetic Marks

the ways in which gene expression is chemically modified by the environment

DNA Methylation (Epigenetic Mark)

a methyl group added to a segment of DNA can turn off a gene

Histone Modification

when DNA wraps itself around proteins called histones

• if a histone’s shapes changes, the transcription of the genetic code can be altered (turning genes off or on)

What sort of life experiences can change the epigenetic tags with which you were born?

Life experiences like diet, physical activity, stress, and exposure to environmental toxins

What sorts of life choices can modify the epigenetic tags that can be passed on to your children?

Life choices like diet, stress, physical activity, and exposure to toxins

Ontogeny

the biological development of an individual organism from its conception to death, encompassing its entire lifespan

Phylogeny

the evolutionary history and relationships among species or groups of organisms, showing how they are related through common ancestors and divergence over time

Cerebral Laterality

the anatomical and functional asymmetry between the left and right cerebral hemispheres

(no function is 100% lateralization)

Vision for Cerebral Lateralization

Left: better at recognizing words and letters

Right: better at recognizing faces, emotions, and geometrical patterns

Hearing for Cerebral Lateralization

Left: better at interpreting spoken language

Right: better at analyzing other sounds like music

Memory for Cerebral Lateralization

Left: better at processing verbal memory and finding meaning in memories

Right: better at processing nonverbal memory and recalling perceptual aspects of memories

Skills

Left: speech, reading, writing, and arithmetic

Right: spatial reasoning, rotating objects in the mind, discerning distance or direction

Split Brain

sever between the corpus callosum

• prevents communication across the hemispheres

• so one hemisphere can complete one task while the other completes another

Electroencephalography (EEG)

detects the electrical activity of large groups of neurons in the surface layer of the cortex using electrodes that stick to the skin

Function of the EEG

to examine the brain’s electrical brain activity when individuals who are awake engage in a variety of psychological functions

Drawbacks of EEG

• does not indicate the precise location of where activity occurs

• does not record activity of neurons in brain structures deeper than the cortex

Structural Brain Imaging

allows us to create images of the brain’s structure and anatomy

Computerized axial tomography scans (CAT)/(CT)

a series of X-rays combined to create three-dimensional images; each X-ray is a somewhat fuzzy image of a slice of the brain along one plane

Magnetic Resonance Imaging (MRI)

uses a strong magnetic field to create high resolution images, only shows soft tissues

Diffusion Tensor Imaging (DTI)

an MRI adapted to image long myelinated axons in the white matter pathways connecting brain regions to coordinate accomplishments

Functional Brain Imaging

provides information about neural activity in different brain regions

Position Emission Tomography (PET)

shows the area of the brain most active during a particular cognitive task by detecting changes in blood flow

Functional Magnetic Resonance Imaging (fMRI)

shows which brain regions are most active during a cognitive task by detecting areas using the greatest amount of oxygen

• can localize changes in brain activity across briefer periods than PET

Transcranial Magnetic Stimulation (TMS)

delivers a magnetic pulse that passes through the skull and can briefly affect the cerebral cortex’s neural activity (which deactivates neurons for a short period of time)

Explain the difference between CT, MRI, fMRI, EEG, and PET

• CT uses X-rays

• MRI uses magnets and radio waves

• PET uses a radioactive tracer

• EEG uses electrodes on the scalp

• fMRI measures blood flow and oxygenation