Psychology: Chapter 1

confounding variable

a factor other than the independent variable that might produce an effect in an experiment

scatterplot

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)

correlation

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

experiment

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

random sample

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

operational definition

a statement of the procedures (operations) used to define research variables ex: human intelligence may be operationally defined as "what an intelligence test measures"

correlation coefficient

a statistical index of the relationship between two things (from -1 to +1)

survey

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

hypothesis

a testable prediction, often implied by a theory

population

all the cases 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]

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

theory

an explanation using an integrated set of principles that organizes observations and predicts behaviors or events

case study

an observation technique in which one person is studied in depth in the hope of revealing universal principles

random assignment

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

confounding variables

by using *random assignment*, researchers are able to control for ___________ which are other factors besides the independent variable(s) that may influence research results

how are correlational research methods conducted?

collect data on two or more variables; no manipulation

double-blind procedure

controls for the placebo effect; neither researchers nor participants know who receives the real treatment

how are descriptive research methods conducted?

do case studies, naturalistic observations, or surveys

what are the weaknesses of the correlational research method?

does not specify cause and effect

placebo effect

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

random assignment

helps minimize preexisting differences between experimental and control groups

random sampling

helps researchers generalize from a small set of survey responses to a larger population

experimental group

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

control group

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

how are experimental research methods conducted?

manipulate one or more factors; use random assignment

what are the weaknesses of the descriptive research method?

no control of variables; single cases may be misleading

what is manipulated in the correlational research method?

nothing

what is manipulated in the descriptive research method?

nothing

naturalistic observation

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

replication

repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances

what are the weaknesses of the experimental research method?

sometimes not feasible; results may not generalize to other contexts; not ethical to manipulate certain variables

independent variable

the experimental factor that is manipulated; the variable whose effect is being studied

what is manipulated in the experimental research method?

the independent variable(s)

dependent variable

the outcome factor; the variable that may change in response to manipulations of the independent variable

hindsight bias (I-knew-it-all-along phenomenon)

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

critical thinking

thinking that does not blindly accept arguments and conclusions; rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions

what is the basic purpose of the correlational research method?

to detect naturally occurring relationships; to assess how well one variable predicts another

what is the basic purpose of the experimental research method?

to explore cause and effect

what is the basic purpose of the descriptive research method?

to observe and record behavior