Science Practice Vocabulary (ALL TERMS)

experiment

a research method where scientists change one factor while controlling everything else and randomly assign participants to groups, allowing them to determine cause and effect

experimental group

the group of participants who receive the treatment or intervention being studied, allowing researchers to measure its effects

control group

the group of participants who do not receive the treatment, serving as a comparison to show what would happen without the intervention

random assignment

placing participants into different groups using a random method (like flipping a coin) so that each group is similar at the start, which helps researchers determine what truly causes changes in results

double-blind study

a research procedure where neither the participants nor the researchers know who receives the real treatment, preventing expectations from influencing results

independent variable

the factor that a researcher controls and changes on purpose to test its effect (think: 'I' control it)

confounding variable

an uncontrolled factor that could affect the results, making it unclear whether the independent variable or this other factor caused the observed changes

dependent variable

the outcome that researchers measure to see if it was affected by the changes made (think: it 'depends' on what the researcher did)

descriptive statistics

a broad category of methods for summarizing and organizing data from a sample, as opposed to making inferences about a larger population

frequency histogram

a bar graph where the height of each bar shows how many times a particular score or value appears in a data set

mode

the most frequently occurring score(s) in a distribution

mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores

median

the middle score in a distribution; half the scores are above it and half are below it

skewed distribution

a representation of scores that lack symmetry around their average value, typically caused by outliers or extreme scores pulling the distribution in one direction

range

the difference between the highest and lowest scores in a distribution

standard deviation

number showing the typical distance of scores from the mean—tells you if data points are tightly grouped or widely spread

normal curve (distribution)

a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (about 68 percent fall within one standard deviation of it) and fewer and fewer near the extremes

inferential statistics

a broad category of statistical methods that allow researchers to draw conclusions about populations based on sample data and test hypotheses

statistical significance

a measure indicating that the results of a study are probably real and not just due to random chance or luck

placebo effect

a change in symptoms or behavior that occurs simply because a person believes they are receiving treatment, even when the treatment has no real therapeutic effect

experimenter bias

when a researcher's expectations about a study's outcome unintentionally affect how they conduct the experiment or interpret the results

placebo

an inactive substance or fake treatment given to participants in a study, designed to look identical to the real treatment being tested

single-blind study

a research procedure where participants don't know which group they're in, but the researchers do know, helping reduce participant bias

quasi-experiment

a study comparing groups that already exist naturally rather than using random assignment, which limits the ability to prove causation

frequency distribution

an organized display showing how often each score or value appears in a data set, arranged to reveal patterns

measures of variation

a category of statistics (such as range and standard deviation) used to describe how spread out or different scores are in a data set

measures of central tendency

a category of statistics (such as mean, median, and mode) used to identify the typical or most representative score in a data set

bimodal distribution

a data pattern that has two different scores that appear most frequently, creating two peaks when graphed

percentile rank

a score's position in a group expressed as the proportion of people who scored lower, ranging from 0 to 100

p-value

a number between 0 and 1 that tells researchers how likely it is that their results happened by random chance rather than because of what they were testing

effect size

any measure of the strength or importance of a relationship between two variables; indicates the practical significance of a research finding

regression toward the mean

the tendency for extreme scores or performances to be closer to average when measured a second time, simply due to natural variation

psychology

the scientific discipline that studies behavior and mental processes using systematic research methods

psychodynamic perspective

the view that behavior is influenced by unconscious thoughts, hidden conflicts, and childhood experiences that people aren't fully aware of

cognitive perspetive

the view that behavior is influenced by how people process information, including how they perceive, remember, think, and solve problems

behavioral Perspective

the view that behavior is shaped by environmental consequences like rewards and punishments, as well as by observing and imitating others

humanist perspective

the view that behavior is driven by each person's potential for growth and self-fulfillment, emphasizing free will, personal choice, and inherent goodness

biological Perspective

the view that behavior is influenced by genetics, brain chemistry, hormones, and the nervous system

socio-cultural perspective

the view that behavior is shaped by cultural values, social norms, and the immediate social context in which people live

evolutionary perspective

the view that behavior patterns exist because they helped our ancestors survive and reproduce, passing advantageous traits to future generations

biopsyhosocial perspective

the view that behavior results from biological, psychological, and social-cultural factors interacting together

clinical psychologist

a mental health professional who diagnoses and treats psychological disorders through therapy and assessment, but cannot prescribe medication

clinical psychiatrist

a medical doctor who specializes in mental health and can diagnose psychological disorders, prescribe medication, and provide treatment

Hindsight bias

the tendency to believe, after learning an outcome, that one would have predicted it

Hypothesis

testable prediction about the relationship between variables, often used to guide research

Operational definition

precise description of how variables will be measured or changed in a study, allowing others to replicate it

Replication

repeating a study using the same procedures to verify the original results are reliable

Survey

research tool that asks people to self-report their attitudes, beliefs, or behaviors, typically through questionnaires or interviews

Sampling bias

flaw in how participants are selected that results in a sample that doesn't accurately represent the population

Population

the entire group a researcher wants to learn about and draw conclusions about

Random sample

a sample in which every member of the population has an equal chance of being selected, reducing bias

Informed consent

an ethical principle that research participants be told enough to enable them to choose whether they wish to participate

Debriefing

the explanation of a study given to participants after it ends, including its true purpose and any deceptions used, to ensure they leave fully informed

American Psychological Association (APA)

professional organization representing psychologists in the United States

Informed Assent

The agreement of someone not able to give legal consent to participate, such as children

Deception

misleading participants about the study's true purpose or what happens to them, which must be revealed during debriefing

Confederate

An actor recruited by the researcher to "play the role" of a participant in the study

Confidentiality

protecting participants' privacy by keeping their information private and secure and not revealing their identities without permission

Anonymous

protecting the identities of the people involved in a study by changing or omitting their names or other identifying characteristics

Institutional Review Board (IRB)

a group that reviews psychological research and decides whether it meets ethical guidelines

Protection from harm

during a research study, participants should not experience negative physical or psychological effects they wouldn't typically experience

Overconfidence

tendency to overestimate our knowledge and abilities

Confirmation bias

tendency to search for information that supports our beliefs and to ignore or distort contradictory evidence

Falsifiability

ability to test whether a theory could be proven wrong through evidence

Peer review

process by which the procedures and results of a study are evaluated by other scientists who are in the same field or who are conducting similar research

Convenience sample

using respondents readily accessible to the researcher

Representation of participants

sample that accurately represents the studied population

Generalizability

extent to which research findings from a sample can be applied to the broader population

Self-report bias

bias when people report their behavior inaccurately

Social desirability bias

tendency to respond to questions in a socially desirable manner

Qualitative Research

research focused on describing experiences and behaviors through detailed observations and interviews, typically reported in words rather than numbers

Structured interview

research procedure in which all participants are asked to answer the same questions

Quantitative research

research that uses numerical measurements and math to study variables and test hypotheses

Likert scales

rating system that measures attitudes, opinions, or behaviors by asking respondents to choose from a range of answer options (i.e. strongly agree to strongly disagree)

Wording effects

when a specific wording used in a question affects how respondents answer the question

Case study

in-depth investigation of a single individual or group to understand complex behaviors or rare conditions

Naturalistic observation

recording behavior in naturally occurring situations without trying to manipulate and control the situation

Correlation

statistical relationship between two variables that indicates how they relate to each other, but does not involve manipulation or prove causation

Correlation coefficient

numerical value between -1 and +1 that indicates the strength and direction of the relationship between two variables

Scatterplot

graph that represents the relationship of two variables in correlational studies

Meta analysis

statistical method that combines results from multiple studies on the same topic to determine whether a finding holds up across studies

Positive correlation

correlation where both variables move in the same direction

Negative correlation

correlation where variables move in opposite directions

Directionality problem

in correlational research, the inability to determine which variable causes changes in the other, since correlation doesn't prove causation

Third variable problem

when two correlated variables are both actually caused by a hidden third factor not considered in the study, creating a misleading relationship between them