IB Psych Unit 1 Test 😊

stratified sampling

A sampling method where the population is divided into meaningful subgroups (strata) based on a specific characteristic (e.g., age, gender, income), and random samples are proportionally selected from each stratum to ensure representation of all groups.

self selected sampling

A non-random sampling method where individuals volunteer to participate in a study, often in response to an advertisement or invitation, which can introduce bias due to participant motivation.

random sampling

A sampling method where every member of the population has an equal chance of being selected, helping to reduce bias and increase the generalizability of the results.

opportunity sampling

A non-random sampling method where participants are selected based on availability and willingness at the time of the study, making it quick and convenient but potentially biased.

Reactivity

A change in a participant’s behavior caused by their awareness of being observed or studied, which can affect the validity of the results.

Carryover effects practice effect, fatigue effect

When participation in one condition of a study influences behavior in a subsequent condition.

Improved performance in later tasks due to repeated exposure or learning from earlier tasks.

Worsened performance in later tasks due to tiredness, boredom, or loss of concentration over time.

Demand characteristics-social desirability effect,screw you effect 

Cues in a study that lead participants to guess its purpose and change their behavior accordingly.

When participants respond in a way they think is more socially acceptable or favorable, rather than being truthful.

When participants deliberately act against the perceived aim of the study to sabotage or resist the research.

placebo

nocebo

A harmless, inactive treatment given to control groups to test the effect of the real treatment, often producing positive effects due to expectations.

A negative effect or symptom caused by a person’s negative expectations or beliefs about a harmless treatment or situation.

IV

The variable that the researcher manipulates or changes to observe its effect on the dependent variable.

DV

The variable that is measured or observed to assess the effect of the independent variable.

True experiment

A study where the researcher manipulates the independent variable and randomly assigns participants to conditions to establish cause-and-effect relationships.

Quasi experiment

A study that examines the effect of an independent variable without random assignment, often using pre-existing groups, making causal conclusions less certain.

Independent samples strengths + limitations

• Reduces practice and carryover effects since participants are only in one condition.

• Simple to implement and avoids order effects.

• Requires more participants than repeated measures designs.

• Individual differences between groups can affect results, potentially increasing variability.

Repeated measures strengths + limitations

• Controls for individual differences because the same participants take part in all conditions.

• Requires fewer participants, increasing efficiency.

• Risk of carryover effects like practice, fatigue, or boredom that can influence results.

• Participants may guess the study purpose, increasing demand characteristics.

Cofounding variable

An outside factor that varies alongside the independent variable, potentially influencing the dependent variable and confusing the results.

Controlled variables

Factors that are kept constant throughout an experiment to prevent them from affecting the outcome.

CARDUD

A checklist acronym to help evaluate research studies:

• Confidentiality

• Access

• Responsibility

• Debriefing

• Understanding (informed consent)

• Deception

It ensures ethical standards are met in psychological research.

Holism

The approach that studies behavior or phenomena as a whole, emphasizing that the whole is more than the sum of its parts.

Reductionism

The approach of breaking complex behaviors or phenomena down into simpler components or causes for easier study and understanding.

Determinism Biological + Environmental

The belief that behavior is caused by factors beyond free will.

• Behavior is controlled by genetics, brain structures, or biochemical processes.

• Behavior is shaped by external factors like upbringing, learning, or culture.

Universalism

The idea that certain psychological principles or behaviors apply to all people, regardless of culture or individual differences.

Relativism 

The view that psychological principles or behaviors are influenced by and vary across different cultures or contexts, so they aren’t universally applicable.

BIAS OVERALL

RESPONSIBILITY OVERALL

CAUSALITY

PERSPECTIVE

Internal Validity

External validity

Construct validity