Psychology Key Concepts: Correlation, Experiments, and Research Methods

Correlate

a measure of the extent to which two factors vary together, and thus of how well either factor predicts the other.

Variables

anything that can vary and is feasible and ethical to measure.

Scatterplots

a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation).

Illusory correlation

perceiving a relationship where none exists, or perceiving a stronger-than-actual relationship.

Regression toward the mean

the tendency for extreme or unusual scores or events to fall back (regress) toward the average.

Experiment

a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant factors.

Experimental Group

in an experiment, the group exposed to the treatment, that is, to one version of the independent variable.

Control Group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.

Randomly Assign

assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the different groups.

Double-Blind Procedure

an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.

Placebo Effect

[pluh-SEE-bo; Latin for "I shall please"] experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent.

Independent Variable

in an experiment, the factor that is manipulated; the variable whose effect is being studied.

Confounding Variable

a factor other than the factor being studied that might influence a study's results.

Dependent Variable

in an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated.

Validity

the extent to which a test or experiment measures or predicts what it is supposed to.

Hindsight Bias

I-knew-it-all-along phenomenon

Overconfidence

Humans tend to think they know more than they actually know (they tend to be more confident than actually correct).

Perceiving Order in Random Events

For most people, an unpredictable world becomes unsettling, which is why we evolved to have a built-in eagerness to make sense of the world.

The Scientific Method

At the foundation of all science is an attitude that combines curiosity, skepticism, and humility.

Constructing Theories

Usually, we use the word 'theory' referring to a mere hunch/speculation.

Theory (In science)

Explains behaviors/events by offering ideas that organize solutions.

Random Sequences

Random sequences don't usually look random.

Coin Flipping

Flipping a coin 50 times and being surprised at how there were streaks of heads and tails.

Streaks in Sports

'Hot' and 'cold' streaks in basketball shooting and baseball hitting.

Streaks in Random Sequences

In actual random sequences, streaks (repeating digits) occur more often than people think they do.

Common Sense Thinking

Overall, Hindsight bias, overconfidence and our tendency to perceive random patterns leads humans to overestimate common sense thinking and the value it holds.

Psychological Finding Example

Tell the first group, for example: 'Psychologists have found that separation weakens romantic attraction. As the saying goes, 'Out of sight, out of mind.''

WREAT

WATER

ETRYN

ENTRY

GRABE

BARGE

Face in the Moon

People could see a face in the moon.

Satanic Messages in Music

Hear Satanic messages in music.

Grilled Cheese Sandwich

See the things on a grilled cheese sandwich.

Sleep affects memory

Helps us organize countless sleep-related observations into a short list of principles.

Good sleep habits

People with good sleep habits tend to answer questions well and do well at test time.

Theory of sleep and memory

The theory that sleep could improve memory must be tested.

Operational definitions

A carefully worded statement of the exact procedures (operations) used in a research study.

Example of operational definition

Human intelligence may be operationally defined as what an intelligence test measures.

Replicate

Repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding can be reproduced.

Case studies

Among the oldest research methods, examines one individual/group in depth.

Purpose of case studies

Hope of revealing things true to all of us.

Brain damage case studies

Much of our early knowledge about the brain came from case studies of individuals who suffered particular impairments after damage to a certain brain region.

Jean Piaget's contribution

Jean Piaget taught us about children's thinking after carefully observing and questioning only a few children.

Animal intelligence studies

Studies of various animals, including only a few chimpanzees, have revealed their capacity for understanding and language.

Naturalistic observations

A descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation.

Small science

Naturalistic observations have mostly been done with pen and paper rather than fancy equipment.

Naturalistic observations on animals

Doing naturalistic observations on animals helps us understand their behavior.

The Survey

A descriptive technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.

Self-reported attitudes

Half of all Americans reported being more happy and joyful than worry and stress on the previous day.

Alien beings belief

1 in 5 people across 22 countries think that alien beings come to Earth and now they walk as humans while disguised.

Importance of religion

Around 5B people say that religion is important for their daily lives.

Wording Effects

Subtle changes to order of wording/questions can have major effects.

Aid to the needy vs. welfare

People approve of 'aid to the needy' more than 'welfare.'

Random Sampling

In everyday thinking we generalize samples that we observe (vivid cases esp).

Sampling bias

A flawed sampling process that produces an unrepresentative sample.

Population

All those in a group being studied, from which samples may be drawn. (Note: Except for national studies, this does not refer to a country's whole population.)

Random sample

A sample that fairly represents a population because each member has an equal chance of inclusion.