1. The Scientific Method and Description
Module 5
The Scientific Method and Description

2. Scientific Method
Theory – an explanation using an integrated set of principles that organizes observations and predicts behaviors or events.
Hypothesis – a testable prediction often implied by a theory
Theory – ADHD/sugar link
Hypothesis: If a kid eats sugar, the kid will act more impulsive, distracted, and hyper
Null hypothesis – the statement that the independent variable will have no effect on the dependent variable (assumed correct until we can encounter scientific evidence to reject it)

3. Scientific Method
Operational definition – statements of the procedures used to define research variables
Determines how we measure the variables
ADHD Ex. - Impulsivity = # of times/hour calling out without raising hand
Allows for replication of study
Eliminates experimenter bias
Replication – repeating a research study usually with different participants in different situations to see whether the basic finding extends to other participants and circumstances

4. Testing and refining theories
Descriptive methods – describe behavior
Case studies, naturalistic observations, surveys/interviews
Correlational methods – associates/link certain factors (relationship between variables)
Experimental methods – manipulate variables to discover their effects (cause and effect)

5. Descriptive Research Methods
Case study – A descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles
Opportunity for insights that one could/would never attempt to gain through designing an experiment (ex) brain injuries, Genie
But: must be careful not to generalize, individual cases may be atypical
Naturalistic Observation - Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.

6. Research Methods
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
Wording effect - the results you get from a survey can be changed by your word selection.
(ex.) Do you have motivation to study hard for this course?
(ex.) Do you feel a desire to study hard for this course?
Only question randomly sampled people
Subject to dishonesty and sampling bias.

7. Populations and Samples
Population (target population)– all those in a group being studied, from which samples may be drawn.
Random sample - a sample that fairly represents a population because each member has an equal chance of inclusion.
The larger the sample the more accurate the study
Stratified sample – subgroups in the population are represented proportionally in the sample
Sampling bias – a flawed sampling that produces an unrepresentative sample
Subject bias – having more knowledge and interest in what is being studied
Volunteer bias – people who volunteer are different from people who don’t volunteer

8. Other Methods of Research
Laboratory Observation – studying behavior in a controlled situation/environment
Benefit of controlling the environment but not natural
Ultimately – general principles revealed help explain everyday behavior
Longitudinal Method – studying the same people over a long period of time
Can accurately study changes over time but people may drop out and it is time consuming
Cross-sectional Method – studying different age groups at the same time in order to understand changes that occur during the lifespan
Less time-consuming but not as accurate – variable of differing generations