General Learning Outcome #1

By: Rafal Zerebecki & Nada Abdel-Hamid

Biological Principles of Analysis

3 Principles that define the biological level on analysis

- Behavior can be innate because it is genetically based.

- Animal research can provide insight into human behavior.

- There are biological correlates of behavior.

Understanding Genetics Approximately 20,000-25,000 genes

Inheritance- Genes and their DNA are passed down from parents to offspring.

Inheritance of DNA plays a key role in human behavior.

Inherited genes are building blocks for complex behaviors (intelligence, criminal behavior, depression).

Individuals have a genetic predisposition towards a certain behavior; however, the behavior may not be revealed unless properly stimulated by the environment

Diathesis-Stress model- illustrates the complexity of forming direct single cause-and-effect relationships between genes and behavior.

Behavior Can Be Innate...

1st Principle- Behavior can be innate because it is genetically based.

Innate= born with You can be born with certain behaviors because they

are based upon your inherited genes.

Nature vs Nurture Debate Can be studied through twin research (together vs

separated), family studies (in-depth of specific family), adoption studies (child vs adopted mother vs biological mother).

An example: Twin Studies

Twin Studies Two types of twins: monozygotic (MZ) and

dizygotic (DZ). MZ twins= one egg; genetically identical (same sex and look very similar). DZ twins=two eggs; not identical and are not any closer genetically than regular siblings (can be different sexes).

If characteristics are inherited, then genetically identical twins should be most similar

An example: Twin Studies Cont. Minnesota Twin Study (Bouchard et al. 1990)

Identical twins raised apart vs. identical twins raised together (most cross-cultural study to date).

Each twin completed approx. 50hrs. of testing and interviews

Concluded that 70% of intelligence can be attributed to genetic inheritance. 30% contributed to some other factors.

Criticism Relied on media coverage to recruit participants No control to establish frequency of contact between

twins before study “Equal environment assumption”

An example: Family Studies A child inherits half of its genes from the mother

and half from the father. Siblings share 50% genes between one

another(excluding MZ twins) Grandparents share 25% with grandchildren First cousins share 12.5% w/ each other

Can be assumed that concordance rates, or correlation found, will increase as heritability increases.

An example: Adoption Studies Allows for the most direct comparison of genetic

and environmental influences of behavior. Adopted children share no genes with the adopted

parent However, they share 50% with natural parent

Could be assumed that if genetics influence behavior the most, then the child will correlate more to natural parent than the adopted parent, despite being raised with the adopted parent and vice versa.

Scarr and Weinberg (1977) and Horn et al (1979)

Focused on parents who raised both adopted and natural children

Found no significant IQ correlation

2nd Principle: Animal Research Can...

Animal research can provide insight into human behavior.

We could study animals that are closely related to humans (chimpanzees) to argue and support certain theories on human behavior.

Number of common behaviors with animals Mate selection, love of mother for offspring,

and self-preservation Facial expressions w/ apes

An example... Tetsuro Matsuzawa (2007)

Examine spatial memory in young chimps. Humans made many errors while chimps showed

great potential. Argued that chimps have better spatial memory

because of an adaptation required for the recollection of food resources.

Memory skills of both chimpanzees and humans have adapted to become most suitable for the respective environments in which they live.

3rd Principle: There are biological... There are biological correlates of behavior

There should be a link between a specific biological factor, such a hormone, and a specific behavior.

Some hormones... Adrenaline- flight or fight response Cortisol- Arousal Testosterone- Development, emotion

Steroids increase testosterone, which increases emotions and development.

explains typical increase in aggression and progressive, quick muscular developments.