Biological Approach Flashcards
(41 cards)
Natural selection.
Individuals who adapt best to their environment will have a greater chance of survival and reproduction, therefore they pass on their traits to their offspring.
Adaptation
When species develop characteristics that make them more competitive in their environment.
Who came up with the social competition hypothesis?
Price (1994)
Evolutionary Psychology
Genes that carry reproductive and survival advantages are passed down through natural selection.
Social Competition Hypothesis
- views depression as an “involuntary subordinate strategy” that evolved to reduce aggression and enhance survival in competitive situations
- reduced motivation and social withdrawal when there is no benefit
- resource holding potential: ability to win influences whether individuals adopt attack or subordinate self-esteem strategy.
Evaluating Social Competition Hypothesis
Strengths:
- Explains higher depression rates in females due to greater parental investment.
- Supported by animal research (e.g., Raleigh et al., 1984).
- Depressed individuals often avoid competition more than others (Kupferberg et al., 2016).
Limitations: - Implies treatment through social hierarchy adjustment, which may be impractical.
- Overlooks cognitive and biochemical aspects of depression.
- Lacks concrete evidence on the role of behavior in inclusive fitness.
Raleigh et al
Aim: Explore the relationship betwen social status and seratonin (associated with depression symptoms).
Method:
-: Researchers formed groups of three male monkeys, three female monkeys, and their offspring.
Observation: Adult males were observed for at least 5 months and categorized as dominant or submissive based on an observation schedule.
- a natural change occurred where a previously submissive monkey became dominant, and the former dominant monkey became submissive.
- Serotonin levels were measured before and after the hierarchy changes using blood samples.
Findings/Evaluation of Raleigh et al:
- Seratonin levels increased in those that became dominant, decreased in those that became submissive.
- Lower S levels are correlated with depression, social withdrawal, etc..
- those that have lower S levels tend to avoid conflict, increased survival and reproductive success.
- it eliminates the limitation of bidirectional ambiguity as it uses a pre-test/post-test design.
- limited generalizability to humans as does not predict human social outcomes.
- does not adress cognitive or sociocultural
Pathogen Host Defense Hypothesis:
the depressive symptoms that increase the risk for depression also increase immunity to infectious diseases. A gene for neuropeptide Y (stress NP), makes it more difficult for individuals to cope with stress, making the immune system activated and increasing inflammation response.
Raison et al
Aim: To test if genes associated with depression are also associated with higher immunity.
Method:
- Gave infliximab (anti-inflammatory drug) to depressed patients.
Findings:
- those who showed higher levels of inflammation, drug reduced depressive symptoms.
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Behavioral Genetics
Understanding how both genetics and the environment contribute to individual variations in human behavior.
Diathesis Stress Model
Psychological theory that explains behavior as a genetic pre-disposition that is expressed as a result of life experiences.
Monozygotic Twins
- Identical Twins that develop from one fertilized egg.
Concordance Rate
The probability that the same trait will be present in a pair of twins.
Dizygotic Twins
Twins that developed from two fertilized eggs.
Limitations to twin studies:
- twins are vary rarely raised apart»_space; difficult to isolate environmental as a variable.
- Equal environment fallacy (not similar).
- Twins are not representative of the general population.
Family Studies Evaluation:
- more representative of the general population.
- limit the overall genetic variability of the sample.
- more controlled than studies of unrelated people.
- difficult to obtain reliable data that goes back many generations (most data in kinship studies is anecdotal data).
Weissman et al (for genetics):
A: To study the potential genetic nature of MDD.
M: 161 grandchildren, their parents, and grandparents including families with a high or low risk of depression.
- 20-year longitudinal study
- Conducted interviews with the parents and childrens.
- Data was collected by clinicians blind to past diagnoses, children were observed by a child psychiatrist and a psychologist.
F:
- High rates observed in granchildren with two gens of MDD.
- 60% of grandchildren showed signs of psychiatric disorders (anxiety disorders esp).
- Increased risk of psych disorders if both grands and parents had a history of depression.
- higher depression rates in parents showed higher rates of mood disorders in children.
if parent was depressed but grands had no history > no impact on grandchildren.
Why are animal models used?
1) Shorter Lifespan + Shorter generation time > observing variables’ effects
2) Provide a better understanding than examining brain lesions in patients (damaged, change in structure to compensate for damage).
3) Animal behavior can be studied in. controlled environment.
Importance of animal models:
- Scientists can create ‘‘animal models’’ by specific endophenotype, or genetic markers, which are related to certain behaviors. > helps scientists understand the biochemical and genetic factors that may lead to depression.
Critsicim of Animal models
1) Different animal pysiology + Highly controlled environment»_space; Low external validity.
2) Inability of animals to verbally communicate their feelings > Researchers must observe behavior > researcher bias > lower reliability.
LeDoux (The Important role of animal models, particularly lesions):
A: To understand wat happens to the brain during a fear response.
F: He determined that the amygdala played an important role in the fear response by lesioning in rats.
- Proposed that there are two paths a fear response can take (low path, when the visual thalamus sends a message to the amygdala when seeing something fearful) (High path, the thalamus’ visual message passes through the visual cortex and the hippocampus to interpret its meaning, the amgydala lowers blood pressure if it is not perceived as a threat).
Brady (1958):
A: The effect of stress on business executives.
M: - Allocated to one of two conditions (executive or yoked).
- Monkeys received an electric shock every 20 seconds for 6 hours over 3 weeks.
- The executive monkey could pull a lever to stop the shock, but the yoked money was caged and could not.
F:
- The executive monkeys developed ulcers and died, no negative effects were shown in the yoked monkeys.
- Increased stomach acid as a result of stress led to the ulcers.
E:
- They were not randomly allocated.
- Highly unethical
- lacks external validity.
The 1966 USA Animal Welfare Act
- Animal dealers must be registered and licensed.
- Lab animals must be overseen by a vet + someone not associated with the facility.
- Committee must asses animal care treatment & practices + ensure that alternatives to animal use in are used when possible.
