The Scientific Method

Scientific Instruments

Accurate, precise

interobserver agreement

Agreement between observations of two or more independent observers.

Nonscientific (everyday) Concepts

Ambiguous, with surplus meanings

Nonscientific (everyday) Reporting

Biased, subjective

Nonscientific (everyday) Observation

Casual, uncontrolled

Scientific Concepts

Clear definitions, operational specificity

Scientific Attitude

Critical, skeptical

We use the term concepts to refer to relationships

among things or events, as well as to their characteristics

Scientific General approach

Empirical

Nonscientific (everyday) Instruments

Inaccurate, imprecise

Nonscientific (everyday) General approach

Intuitive

Nonscientific (everyday) Measurement

Not valid or reliable

Scientific Observation

Systematic, controlled

Scientific Hypotheses

Testable

Scientific Reporting

Unbiased, objective

Nonscientific (everyday) Attitude

Uncritical, accepting

Nonscientific (everyday) Hypotheses

Untestable

Scientific Measurement

Valid and reliable

in scientific reporting, observers must guard against

a tendency to draw inferences too quickly

Scientific instruments are

accurate and precise

One problem of an operational definition there is nothing to prevent us from giving a construct

another operational definition

Scientists seek to determine whether any differences in their observations of the dependent variable

are caused by the different conditions of the independent variable

Dependent variables are measures of behavior used to

assess the effects of independent variables

Operational definitions facilitate communication

at least among those who know how and why they are used

An operational definition explains a

concept solely in terms of the observable procedures used to produce and measure it

We use the term concepts to refer to things

both living and inanimate

Scientists gain the greatest control when they

conduct an experiment

The study of "concepts" is so important in psychological science that researchers refer to concepts by a special name

constructs

The accuracy of an instrument is determined by

calibrating it, or checking it with another instrument known to be true

everyday observations are not always made

carefully or systematically

testable hypotheses have

clearly defined concepts (operational definitions), are not circular, and refer to concepts that can be observed

A construct is

concept or idea

One way in which a scientist gives meaning to a construct is by

defining it operationally

The measures of behavior that are used to assess the effect (if any) of the independent variables are called

dependent variables

One type of scientific measurement, physical measurement, involves

dimensions for which there is an agreed-upon standard and an instrument for doing the measuring

operational definitions are not always meaningful

does performance on one test compare to performance on other tasks that are commonly accepted as measures of the construct

reliability of a measurement is

indicated by its consistency

In a sense, the human observer is the

instrument for psychological measurement

illusory correlation

is our tendency to perceive a relationship between events when none exists.

In an experiment, scientists

manipulate one or more factors and observe the effects of this manipulation on behavior

In most psychological research, however, the measurements do

not involve physical dimensions

clear communication of constructs occurs when

operational definitions are used

Measurements can be made at varying levels of

precision

independent variable two levels often represent the

presence and the absence of some treatment, respectively

agreement among a number of observers provides the basis for

psychological measurement

Scientists use two types of measurements to

record the careful and controlled observations that characterize the scientific method

in an experiment

researchers manipulate independent variables to determine their effect on behavior

One way to determine whether a report is unbiased is to

see if it can be verified by an independent observer

The scientific method is empirical and requires

systematic, controlled observation.

A hypothesis is a

tentative explanation for a phenomenon

Clear, unambiguous communication of ideas requires

that we clearly define our concepts

validity refers to

the "truthfulness" of a measure

the condition in which the treatment is absent is called

the control condition

Accuracy refers to

the difference between what an instrument says is true and what is known to be true

The condition in which the treatment is present is commonly called

the experimental condition

a major strength of using operational definitions is that

they help to clarify communication among scientists about their constructs

We use the term concepts to refer to events

things in action

In the simplest of studies, the independent variable has

two levels

Scientific reporting is

unbiased and objective

Scientific reporting seeks to be

unbiased and objective

physical and psychological measurement should be

valid and reliable

One possible basis for the illusory correlation bias is that

we are more likely to notice events that are consistent with our beliefs than events that contradict our beliefs

To determine whether a different procedure or test yields a new definition of a construct

we would have to seek additional evidence

When scientists report their findings, they seek to separate what they have observed from

what they conclude or infer on the basis of these observations

events should be described in sufficient detail

without including trivial and unnecessary minutiae

a literal description in reporting

would not be appropriate