2.2 TO WHAT EXTENT DOES GENETICS INFLUENCE BEHAVIOR?Back up your response with research

BEHAVIORAL GENETICS

Behavioral genetics deals with the understanding of how both genetics and the environment contribute to individual variations in human behavior.

Is a single gene responsible for complex behaviors? NO, behaviors is brought about through a series

of building blocks (genes)

DIATHESIS STRESS MODEL Diathesis stress model argues that

depression may be the result of the interactions of a “genetic vulnerability” and traumatic environmental stimuli in early childhood.

BUT…..do all siblings raised in the same environment develop depression …..? There is no single cause and effect relationship

between genes and behavior.

GENETIC RESEARCH

GENETIC RESERCH Method of Study: Correlation

How different variable may co-vary No manipulation of the variables, thus no cause

and effect can be established.

TWIN STUDIES, FAMILY STUDIES & ADOPTION STUDIES Twin Studies

Monozygotic (100%) vs dizygotic (50%) The higher the genetic relationship, the more

similar the individuals should be in the trait being inherited.

Concordance rate = correlation found in twin studies.

Family Studies More representative of the population

Adoption Studies Allow the comparison of biological and

environmental influences Not representative of the population

Criticized for selected placement

INTELLIGENCE (REFERENCE PG 54) Is intelligence inherited or is it the result of

the environment? What is intelligence? How can it be measured?

BE A THINKER: ON THE INTERNET YOU WILL FIND FREE IQ TEST. GO ONLINE AND TAKE AT LEAST THREE DIFFERENT TESTS. EACH TEST SHOULD GIVE YOU A SCORE.

1. Do you think that these tests appropriately evaluate your intelligence?

2. Do you feel that the tests were adequate? Why or why not?

3. How would you change the tests to make them reflect more accurately what you consider to be your intelligence?

RESEARCH IN INTELLIGENCE Meta-analysis: the statistical synthesis of

the data from a set of comparable studies of a problem that yields a quantitative summary of a pooled result. Example: Bouchard and McGue (1981) reviewed

111 studies of IQ correlation between siblings from research on intelligence from around the world.

Results: the closer the kinship the higher the correlation for IQ.

BOUCHARD (1990) MINNESOTA TWIN STUDY IS

A longitudinal study (1979) of MZ raised apart vs MZ raised together.

70% IQ attributed to genetic inheritance 30% IQ to other factors

Criticism of the study: Self selected sampling. Bouchard relied on the

media to recruit participants Ethical concerns about reuniting the twins No adequate control to establish frequency of

contact between twins prior to study. Cannot assume twins raised in same environment

received identical treatment.

SCARR & WEINBERG (1977) AND HORN ET AL., (1979)

ADOPTION STUDIES Adoptive children and natural biological

children raised by the one biological parent should demonstrate no difference in IQ if environment is the contributing factor in intelligence.

Researchers found no significant difference in IQ correlations Adoptive parents were wealthy, white, middle

class, high IQ Adopted children were from poor, lower class

background, with lower IQ parents.

WAHLSTEN 1997 Transferring an infant from a low-socio-

economic status to a home where parents have a higher socioeconomic status improved IQ by 12-16 points.

Enriched environment?

CONCLUDING THOUGHT ON INTELLIGENCE Is intelligence based on knowledge or the

ability to problem solve? Hainer et al. (1988)

“Less Effort Hypothesis” When problem solving (reasoning) individuals

with high IQ had lower metabolic rates than those with low IQ

Plomin and Petrill (1977) Socio-economic class appears to be an important

environmental factor in developing intelligence. “Poverty - not genetic inferiority – is key to

understanding the differences in intelligence.”

CONCLUDING THOUGHT ON INTELLIGENCECONT., The Flynn Effect

The rise in average scores of IQ tests in most parts of the world over the last century.

Neisser, 1997 documented : The average score increase by 3 points every 10

years Cause is unknown

Is it an increase in intelligence? Is it the ability to manipulate the test taking process? Does better nutrition , improved education, added

technology add to the effect? What effect does the highly visual environment have ?

SOCRATIC SEMINAR : THE NATURE OF INTELLIGENCEIB Question: To what extent does genetic inheritance influence behavior?

THE SEMINAR WILL FOCUS ON 3 QUESTIONS1. How do we define intelligence – and why does it

matter?2. To what extent is intelligence biological? (what

are the strengths and limitations of a purely biological argument?)

3. Can intelligence change over time? What are the implications for schools if we find that intelligence has a biological basis and cannot be changed?

You will use the information gathered to create a graphic organizer to answer the question: To what extent does genetic inheritance influence behavior?

2.2 WHAT ROLE DOES EVOLUTION HAVE IN BEHAVIOR?

DARWIN,(1871) “THE DESCENT OF MAN” Humans have a number of behaviors in

common with animals. Mate selection Love of mother to offspring Self-deprivation Facial expressions humans share with primates. Humans share many of the same feelings as

animals

EVOLUTION AND SPATIAL MEMORYTETSURO MATSUZAWA (2007) Do chimps have better spatial memory than

humans?

Read study

EVOLUTIONARY PSYCHOLOGY As genes mutate, those that are

advantageous are passed down through natural selection.

Evolutionary Psychologist attempt to explain how certain human behaviors explain the development of our species over time.

Natural selection does not select the behavior – it only selects the mechanisms that produces the behavior. Fessler (2006) – evolution of disgust. (pg. 58) Curtis et al., (2004) -

EXAMINING THE EVOLUTIONARY ARGUMENT – THINGS TO CONSIDER Difficult to prove empirically

susceptible to conformational bias - they see what they expect.

Little is known about behavior of early Homo sapiens

Cultural differences are often overlooked as a role in evolutionary differences.

ETHICAL CONSIDERATIONS IN RESEARCH INTO GENETIC INFLUENCES OF BEHAVIOR How will the participants privacy be

protected? What will happen to any of the genetic

material obtained from the study? Informed, written consent must be given,

with the full understanding of the aim of the research.

Confidentiality and full anonymity Protect from insurance co., employers, police

military etc. What do you do if the results show

information that can harm the participant? Misidentified paternity, adoption, genetic

disorders.