Atlas MCAT Course
Psychological & Social Foundations → Social Structure, Inequality, Health, & Research Methods
Social Structure, Inequality, Health, & Research Methods
The systems layer.
01The idea
Social structure refers to the stable patterns that organize society: institutions (education, healthcare, economy), roles and statuses, and norms and rules.
This explains why similar individuals can have very different outcomes.
THREAD · Constraints over choices
02Build the model
AStratification and inequality: unequal distribution of life chances
| Form | What it involves |
|---|---|
| Socioeconomic status (SES) | Income, education, occupation |
| Race/ethnicity | Social categories with real consequences |
| Gender | Roles and expectations embedded in institutions |
| Age | Cohort effects and life-course position |
BPoverty: absolute vs. relative
Absolute poverty is the inability to meet basic needs. Relative poverty is deprivation compared to societal standards. Relative poverty is especially important for stress, social exclusion, and health disparities.
CSocial mobility: movement within the structure
Intragenerational mobility happens within one lifetime; intergenerational mobility happens across generations. Barriers to mobility include unequal education access, network effects, and wealth accumulation differences.
DSocial determinants of health: why health is unequal
Health outcomes reflect more than biology. Major determinants: SES, education, neighborhood environment, access to care, and discrimination and chronic stress.
EStress, inequality, and health
Chronic exposure to stressors increases allostatic load, dysregulates physiological systems, and increases disease risk. Stressors include financial insecurity, discrimination, and environmental hazards.
FEpidemiology: studying health in populations
Epidemiology examines incidence (new cases over time) and prevalence (total existing cases).
Each design trades cost, bias, and causal inference strength.
GDemography: population patterns over time
Key metrics: birth rate, death rate, fertility rate, and migration rate.
HCulture: shared meaning systems
Culture includes beliefs, values, norms, and symbols. It shapes health behaviors, influences help-seeking, and defines stigma and illness meaning. Ethnocentrism is judging others by one’s own standards; cultural relativism is understanding practices in context.
IDeviance and social control
Deviance is the violation of norms; social control is the set of mechanisms enforcing conformity. Sanctions may be formal (laws, policies) or informal (approval, shaming). Deviance is context-dependent, not inherent.
JResearch methods: how knowledge is generated
| Term | Meaning |
|---|---|
| Independent variable (IV) | Manipulated or categorized |
| Dependent variable (DV) | Measured outcome |
| Confounder | Third variable influencing both |
| Reliability | Consistency |
| Validity | Accuracy |
Experimental studies use random assignment and support causal inference; observational studies show association in a real-world context.
Common biases: selection bias, recall bias, observer bias, and social desirability bias.
Statistics (conceptual): correlation ≠ causation; statistical significance means unlikely by chance; practical significance means real-world impact. Interpret results in context, not in isolation.
KEthics: constraints on research
Core principles: informed consent, confidentiality, beneficence, and justice. Ethics protect participants and data integrity.
03See the connections
The lesson names these links itself. Read the map left to right.
Structure
- Institutions, roles, norms
- Stratification and mobility
Health
- Social determinants
- Chronic stress, allostatic load
Evidence
- Epidemiology and demography
- Research design, bias, ethics
Next: foundational psychologists.
04Reason with it
Four questions. Answer in your head first, then choose. You’ll see the reasoning either way.
Think first.
Researchers compare people who already have a disease with people who don’t, and look back at past exposures. What design is this?
Think first.
A scale gives the same wrong weight every time. How would you describe it?
Think first.
Two equally hard-working people end up with very different incomes because of different schools and networks. Which idea explains this best?
Think first.
Why does random assignment strengthen causal claims?
05MCAT lens
The MCAT emphasizes
Structure constrains options and distributes resources
Health disparities are systemic, not random
Study design determines how strong a causal claim can be
Correlation ≠ causation; reliable ≠ valid
06Common traps
Trap 1: Health outcomes are mostly individual choices
Misconception
Health disparities are systemic.
Correct model
Social determinants shape risk.
Trap 2: Randomization removes all bias
Misconception
It reduces confounding.
Correct model
Other biases can remain.
Trap 3: A reliable measure must be valid
Misconception
Consistency isn’t accuracy.
Correct model
A measure can be reliable but invalid.
07Dependency check
Can you reconstruct this concept without looking at the page? You should now be able to reason through:
Why similar individuals have different outcomes
Check against 01 and 02 · A: structure distributes resources.
How social conditions affect biology
Check against 02 · D and E: determinants and allostatic load.
How study designs differ
Check against 02 · F: snapshot, forward, backward.
Why randomization and validity matter
Check against 02 · J: confounding, reliability, validity.
If something feels unclear, the missing idea is usually thisIndividual behavior occurs within structures that constrain options and distribute resources.
08Remember
REMEMBER · if you keep only a few things
- Structure constrains options and distributes resources.
- Stratification is reproduced by institutions.
- Health disparities are systemic.
- Chronic stress → allostatic load → disease risk.
- Cross-sectional: snapshot. Cohort: forward. Case–control: backward.
- Reliable ≠ valid; correlation ≠ causation.
09Forward hook
With the systems layer in place, it helps to know which thinkers framed each model.
Which psychologist goes with which explanatory lens?
That leads to foundational psychologists.
Next lessonFoundational Psychologists→