hindsight bias
the tendency to believe, after learning an outcome-- including a psychological research finding-- that one would have foreseen it. ( I knew it all along phenomenon)
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 and predicts observations.
hypothesis
a testable prediction, often implied by a theory; testing the hypothesis helps scientists to test the theory.
operational definition
a statement of the procedure (operations) used to define research variables. For example, intelligence may be operationallly defined as what an intelligence test measures.
replication
repeating an experiment, often with different participants and in different situations, to see whether the basic finding extends to other people and circumstances.
case study
an observation technique in which 1 person is studied in depth in the hope of revealing things that are true to us all.
survey
a technique for ascertaining the self-reported attitudes or behaviors of people,
usually conducted by questioning a representative, random sample of them
false consensus effect
the tendency to overestimate the extent to which others share our beliefs & behaviors.
population
consists of all the members of a group being studied.
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 or control the situation.
correlation coefficient
a statistical measure that indicates the extent to which 2 factors vary together, and thus how well one factor can be predicted from the other.
positive correlation
the frequency of a variable increases as the other does.
negative correlation
the frequency of a variable decreases as the other increases.
scatterplot
a depiction of the relationship between 2 variables by means of a graphed cluster of dots.
illusory correlation
the false perception of a relationship between 2 events when none exists.
experiment
a research straegy in which a researcher directly manipulates 1 or more factors (independent variables) in order to observe their effect on some behavior or mental process (the dependent variable); they can make it possible to establish cause-effect relat
placebo
an inert substance or condition that is administered as a test of whether an experimental participant, who mistakenly thinks a treatment is in effect, behaves the same as he or she would if the treatment were actually present.
double-blind procedure
a control procedure in which neither the experimenter nor the research participants are aware of which condition is in effect. Used to prevent experimenters' and participants' expectations from influencing the results of an experiment.
placebo effect
any effect on behavior caused by a placebo.
experimental condition
type of condition in an experiment in which participants are exposed to the independent variable being studied.
control condition
type of conditions in an experiment in which the treatment of interest, or independent variable, is withheld so that comparison to the experimental condition can be made.
random assignment
the procedure of assigning participants to the experimental & control conditions by chance in order to minimize preexisting differences between the groups.
independent variable
variable of an experiment that is the factor being manipulated and tested by the investigator.
dependent variable
variable of an experiment that is the factor being measured by the investigator.
mode
the most frequently occurring score in a distribution; the simplest measure of central tendency to determine.
mean
the arithmetic average of a distribution, obtained by adding the scores and then diving them by the number of scores
median
middle score in a distribution--- is the score that falls at the 50th percentile, cutting a distribution in half.
range
the difference between the highest and lowest scores in a distribution
standard deviation
the average amount by which the scores in a distribution deviate around the mean. Because it is based on every score in the distribution, it is a more precise measure of variation than the range.
statistical significance
A statistical criterion for rejecting the assumption of no difference in a particular study