Wrapping Up Biological Basis of Behavior

AP PSYCHOLOGY

Tuesday, November 1

THURSDAY’S TEST

100 multiple choice questions ≈ 75 from Biological Basis of Behavior (Modules 9-14)≈ 10 from Research Methods and Statistics (Module 4-8)≈ 5 from History and Approaches (Modules 1 -3)≈ 10 from Cognition (Modules 31 - 36)

1 Free Response Question worth 30 points

For the genetics and evolution sections, focus on the vocabulary from the reading guides. I will limit that section to no more than 10 questions on the test and will make sure that they come from the reading that was assigned.

THURSDAY’S EXTRA CREDIT PROJECT

Your homework on Thursday after the test is an optional extra credit project. You will have three choices and will only be allowed to complete one.

You will be able to earn up to 30 points extra credit in the “Unit Tests” category of your grade. By the end of the semester, this will work out to about 6% for this category. However, just completing the project will not earn the points. They will be graded based on quality and accuracy.

BRAIN PLASTICITY

Keep in mind that (1) severed neurons usually do not regenerate and (2) some brain functions seem preassigned to specific areas.

However the brain’s neural tissue can reorganize in response to damage.

DEFINITION: The brain’s ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.

The brain is very resilient, figuring out ways to compensate for injury. The younger one is when the injury occurs, the more functioning can be regained

BRAIN PLASTICITY

Certain functions can take over a damaged part of the brain to repurpose that part for a new function. Typically, the new function is related to its original purpose, only it is now used with another sense that has taken over that process. Touch takes over the reading function from

vision that has been lost Constraint-induced theory aims to rewire

brains and improve the dexterity of a brain-damaged child or an adult stroke victim Gaby Giffords – gunshot wound to the left-

hemisphere resulted in lost speech but she has since partly recovered her speaking ability

BROCA’S AREA

Paul Broca observed that brain damage to the left hemisphere in stroke patients resulted in expressive aphasia, or the loss of the ability to speak. In 1861, he performed an autopsy on the brain

of a patient, nicknamed Tan, who had lost the capacity to speak although his mouth and vocal cords weren’t damaged and he could still understand language.

Tan’s brain showed deterioration of part of the frontal lobe of the left cerebral hemisphere, as did the brains of several similar areas.

Conclusion: the left hemisphere is typically specialized for language processing

WERNICKE’S AREA

Carl Wernicke (1874) discovered an area of the left temporal lobe that, when damaged in stroke patients, resulted in receptive aphasia, or the inability to comprehend speech.

Speech is typically fluent but is empty of content, incoherent, or does not make any sense.

SPLIT-BRAIN PATIENTS

Roger Sperry demonstrated that the two hemispheres of the brain can operate independently of each other.

Split-brain patients had their corpus callosum (nerve fibers that connect the hemispheres) severed to control their epileptic seizures. They can describe objects without deficit if presented

in the right visual field which is processed on the left, more verbal, side of the brain, but they have great difficulty drawing the image.

If the image is presented in the left field visual field which is processed on the right, more visual, side of the brain, the person can draw or choose an object, but they cannot explain it verbally.

This is called contralateral processing.

CONTRALATERAL CONTROL

The left hemisphere gets sensory messages and controls the motor function of the right half of the body.

The right hemisphere gets sensory messages and controls the motor function of the left half of the body.

BRAIN LATERALIZATION (aka Hemispheric Specialization)

Definition: The use of one region of the brain more than the other for certain functions

Through the work of Roger Sperry (1913-1994) and Michael Gazzaniga (1939 – present), it was revealed that the left and right hemispheres do not perform exactly the same functions.

Left hemisphere is specialized for verbal, mathematical, and analytical functions.

Right hemisphere is specialized for spatial, musical, and holistic functions such as identifying faces and recognizing emotional facial expressions.

BRAIN LATERALIZATION

For years in popular culture, the terms left-brained and right-brained have come to refer to personality types, with an assumption that some people use the right side of their brain more, while some use the left side more.

Scientist Carl Zimmer wrote in the Discovery magazine that “No matter how lateralized the brain can get, though, the two sides still work together”

DUAL PROCESSING

DEFINITION: The principle that information is often simultaneously processed on separate conscious and unconscious tracks.

This dual processing affects our perception, memory, attitudes, and other cognitions.

Running on automatic pilot allows our consciousness to monitor the whole system and deal with new challenges, while neural assistants automatically take care of routine business. Our unconscious parallel processing is faster

than sequential conscious processing, but both are essential.

BEHAVIOR GENETICS

HEREDITY

Definition: how the traits of parents are transmitted biologically to offspring Physical traits: height, eye color,

susceptibility to disease Behavioral traits: aggression,

intelligence, personality, psychological issues

The nucleus of each human cell contains 46 chromosomes (23 donated from each parent). Gender is based on X and Y chromosomes XX = female XY = male

Each chromosome contains genes made up of DNA Each gene can be either dominant or

recessive

HEREDITY

Genotype: the genetic makeup for a trait in an individual, which may or may not be expressed

Phenotype: the observable characteristics of genes

NATURE vs. NURTURE

Most psychologist now agree that both nature and nurture interact to influence behavior. Nature sets the possibilities for behavior Nurture determine how those possibilities will be realized Visualize a rubber band as your inherited traits, but the environment

determines how much the rubber band “stretches”.

EVOLUTION

Charles Darwin’s theory of evolution explains that gradual change in the expression of particular genes over time occurred because traits that allowed our ancestors to survive were passed on to successive generations. Example: the prevalence of

marriage rituals in human society indicates that this behavior was naturally selected because it maximized the chances that children would survive (two parents are better than one).

HERITABILITY

Heritability: a mathematical measure that indicates the amount of variation among individuals that is related to genes Only an estimate! Only applies to the

population as a whole and not to individuals High heritability means

that most of the differences among a group will be due to differences in their genes (for example, height)

TWIN AND ADOPTION STUDIES

Behavior geneticists study the expression of behavioral traits in individuals by using twin and adoption studies to investigate the influences of nature and nurture and determine heritability estimates. Schizophrenia, intelligence, and alcoholism have all be studied this

way and have show a significant level of heritability

TWIN STUDIES

Comparing identical and fraternal twins Monozygotic (identical) twins Share 100% of the same genes because they developed from a single

fertilized egg Greater likelihood of developing schizophrenia that fraternal twins or

siblings Traits shared by monozygotic twins raised apart are considered to have

high heritability: intelligence, personality, interests, fears, and talents Traits that they differ on are considered to have low heritability

Dizygotic (fraternal) twins Share 50% of the same genes because they developed from two

separate fertilized eggs and are not more genetically similar to each other than to their other siblings

ADOPTION STUDIES

Determining if individuals are more similar to their biological or adoptive parents Traits shared with biological parents = higher heritability Intelligence, personality, and susceptibility to specific mental illnesses

Traits shared with adoptive parents are more influenced by the environment Morals, religious affiliations, and attitudes