Myers Chapter 1

### hindsight bias

the tendency to believe, after learning an outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon)

### overconfidence

the tendency to be more confident than correct, to overestimate the accuracy of one's beliefs and judgments

### critical thinking

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

### theory

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

### operational definition

a statement of the procedures (operations) used to define research variables. For example, human intelligence may be operationally defined as what an intelligence test measures

### 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

### case study

research method that involves an intensive investigation of one or more subjects in hopes of revealing universal principles

### survey

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

### false consensus effect

the tendency to overestimate the extent to which others share our beliefs and behaviors

### random sample

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

### naturalistic observation

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

### stratified random sample

a sample from selected subgroups of the target population in which everyone in those subgroups has an equal chance of being included in the research

### correlation coefficient

a statistical measure of the extent to which two factors vary together, and thus of how well either factor predicts the other; ranges from -1 to +1

### 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). (Also called a scattergram or scatter diagram.)

### positive correlation

A correlation where as one variable increases, the other also increases, or as one decreases so does the other. Both variables move in the same direction.

### negative correlation

the relationship between two variables in which one variable increases as the other variable decreases

### 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.

### placebo

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.

### placebo effect

experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which is assumed to be an active agent

### 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

### experimental condition

the condition of an experiment that exposes participants to the treatment, that is, to one version of the independent variable

### control condition

the condition of an experiment that contrasts with the experimental condition and serves as a comparison for evaluating the effect of the treatment

### random assignment

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

### independent variable

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

### dependent variable

The experimental factor that is being measured; the variable that may change in response to manipulations of the independent variable

### descriptive research

has the purpose of observing and recording behavior; case studies, surveys, and naturalistic observations

### correlational research

the study of the natural relationship between two variables such that systematic changes in the value of one variable are accompanied by systematic changes in the other; allowing us to predict the value of one variable from the other

### mean

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

### standard deviation

a measure of variability that describes an average distance of every score from the mean

### statistical significance

a calculation central to inferential statistics that describes the likelihood that the results of a study happened by chance

### normal curve

the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes; most scores fall near the average, and fewer and fewer scores lie near the extremes