Ch. 2: Methods in Psychology

dogmatists

people who thought the best way to understand illness was to develop theories of the body’s functions

dogmatism

tendency to cling to one’s beliefs

empiricists

people who thought the best way to treat illness was to examine sick people

empiricism

belief that accurate knowledge can be acquired through observation, core of science

scientific method

procedure for using empirical evidence to establish facts

theory

idea of how something works

hypothesis

falsifiable prediction made by a theory

empirical method

set of rules and techniques for observation

operational definition

description of property in measureable terms

construct validity

extent to which the thing being measured adequately characterizes the property

power

ability of operational definition to detect presence of differences or changes in magnitude of property

reliability

ability of operational definition to detect absence of differences or changes in magnitude of property

demand characteristics

participants behavior is shifted toward what they think someone else wants or expects

naturalistic observation

gathering scientific information by unobtrusively observing people in their natural environments

privacy

remove identification information about participants on forms so that they feel more willing to tell the truth

unawareness

use forms of deception to mask intention of study

observer bias

researcher’s expectations influence what they believe they observed

double-blind study

study where neither the researcher nor the participant knows how the participants are expected to behave

frequency distribution

graphic representations showing number of times in which measurement of property takes on each value

mean

average value of all measurements, affected by outliers

median

value in the middle of all measurements

mode

most frequent observed value

range

largest data value - smallest data value, sensitive to extreme values

variability

extent to which measurements in a frequency distribution differ from one another

standard deviation

how measurements in a certain distribution differ from the mean

variables

properties that can have more than one value

correlation

relationship between variables in which variations in the value of one variable are synchronized with variations in the values of the other

correlation coefficient

strength of correlation

natural correlation

correlations we observe in the world around us

third-variable problem

correlation between two variables cannot be taken as evidence of a casual relationship between them because a third variable could be causing them both

experimentation

method for establishing the casual relationship between variables

manipulation

technique for determining the casual power of a variable by actively changing its value

independent variable

variable that is manipulated

dependent variable

variable that is measured

self-selection

problem that occurs when anything about a participant determines the value of the independent variable to which the participant was exposed

random assignment

procedure that assigns participants to conditions by chance

random sampling

a technique for selecting participants that ensures every member of a population has an equal chance of being included in the sample

population

all members of the group you are testing

sample

partial collection of group drawn from the same population

case method

procedure for gathering scientific information by studying a single individual

internal validity

attribute of an experiment that allows it to establish causal relationships

external validity

attribute of an experiment in which variables have been operationally defined in a representative way

replication

an experiment that uses the same procedures as a previous experiment but with a new sample from the same populationc

critical thinking

asking ourselves if we have biases that influenced results and if we have the whole truth

Institutional review board (IRB)

governing body that monitors psychological research involving human participants