Unit 0 - Scientific Foundations of Psychology - AP Psychology

Operational Definition

Clear, precise, quantifiable definition of your variables — allows replication and collection of reliable data

Qualitative Data

Descriptive data (eye colors)

Quantitative Data

Numerical data (Ideal for statistics)

Directionality Problem

Which direction does the correlation go? (Depression causes low self-esteem, low self-esteem causes depression)

3rd Variable Problem

Different variable is responsible for relationship (ice cream & murder)

Positive Correlation

Variables increase & decrease together

Negative Correlation

One variable increases as the other variable decreases

Independent Variable

Purposefully altered by researcher to look for effect

Experimental Group

Received the treatment

Control Group

Placebo, baseline

Dependent Variable

Measured variable, dependent on independent variable

Placebo Effect

Any observed effect on behavior that is caused by the placebo

Double-Blind Experiment

Experiment where neither the participants nor the experimenter are aware of which condition people are assigned

Single-Blind Experiment

Experiment in which only participants are blind to which condition people are assigned

Confounding Variable

Error/flaw in study that is accidentally introduced

Random Assignment

Assigns participants to either control or experimental group at random - increases chance of equal representation among groups

• ALLOWS you to say cause/effect

Naturalistic Observation

Observes people in their natural settings

• Adv: Real world validity

• Disadv: No cause/effect

Case Study

Studies one person in great detail

• Adv: Collects lots of info

• Disasv: No cause/effect

Meta-analysis

Combines multiple studies to increase sample size and examine effect sizes

Descriptive Statistics

Shows shape of the data

Mean

Average (use in normal distribution)

Median

Middle # (used in skewed distribution)

Mode

Occurs most often in a data set

Bimodal distribution

Has two modes, usually indicates good/bad scores

Negatively Skewed Distribution

Mean is to the left, mode is to the right

Positively Skewed Distribution

Mean is to the right, mode is to the left

Range

Distance between smallest and biggest #

Standard Deviation

Average amount the scores are spread from the mean (bigger # = more spread)

Inferential Statistics

Establishes significance (meaningfulness)

Statistical Significance

Results not due to chance (smaller # = better)

Effect Size

Data has practical significance (bigger = better)

Confidentiality (ethical guidelines)

Names & info kept secret

Informed Consent (ethical guidelines)

Must agree to be part of study

Informed Assent (ethical guidelines)

Minors AND their parents must agree

Debriefing (ethical guidelines)

Must be told the true purpose of the study (done after for deception)

No harm (ethical guidelines)

No mental nor physical harm

Surveys

Usually turned to correlation, subject to self report bias

Social desirability (Surveys)

People lying to look desirable/good

Wording effects (Surveys)

How you frame the question can impact your answers

Random Sample

Method for choosing participants for your study — everyone has a chance to take part, increases generalizability

Representative Sample

Sample mimics the general population

Convenience Sample

Select participants on availability — less representative & less generalizability

Sampling Bias

Sample isn’t representative, due to convenience sampling

Cultural norms

Behaviors of a particular group can influence research results

Experimenter/participant bias

Experimenter/participant expectations can influence the outcome

Cognitive bias

Bias in thinking/judgement

Confirmation bias (cognitive)

Only searching for info that supports pre-existing beliefs

Hindsight Bias (cognitive)

Thinking you could’ve known the outcome “all along”

Overconfidence (cognitive)

Overestimate our knowledge/abilities

Hawthorne effect (cognitive)

People changing behavior when watched