1. The Characteristics of an Experimental Hypothesis
The Inductive Model
The Deductive Model
Combining Induction and Deduction
Building on Prior Research
Serendipity and the Windfall Hypothesis
Intuition
When All Else Fails
Searching the Research Literature

2. What is a hypothesis?
A hypothesis is an explanation of a relationship between two or more variables.
The Characteristics of an Experimental Hypothesis

3. What is an experimental hypothesis?
An experimental hypothesis is a tentative explanation of an event or a behavior. It is a statement that predicts the effect of an independent variable on a dependent variable. For example, cognitive behavior therapy (CBT) produces less relapse than antidepressants.
The Characteristics of an Experimental Hypothesis

4. What is an nonexperimental hypothesis?
A nonexperimental hypothesis predicts how variables (events, traits, or behaviors) might be correlated, but not causally related.
For example, red-haired patients receive less relief from pain medication than blonde patients.
The Characteristics of an Experimental Hypothesis

5. Why must a hypothesis be a synthetic statement?
When we state a hypothesis, we then gather data that either support or contradict it.
For this reason, a hypothesis must be capable of being true or false, which is a property of synthetic statements.
The Characteristics of an Experimental Hypothesis

6. What is testability and why is it important?
An experimental hypothesis is testable when it can be assessed by manipulating an IV and measuring the results on the DV.
Without testability, we cannot evaluate the validity of a hypothesis.
The Characteristics of an Experimental Hypothesis

7. Why should hypotheses be parsimonious?
Parsimony means that we prefer a simple hypothesis over one requiring many supporting assumptions. A simple hypothesis allows us to focus our attention on the main factors that influence our dependent variable.
The Characteristics of an Experimental Hypothesis

8. Explain the inductive model of formulating a hypothesis.
Induction is reasoning from specific cases to general principles to form a hypothesis. Researchers use inductive reasoning to construct theories by creating explanations that account for empirical data (observations).
The Inductive Model

9. How can we build a theory using induction?
Scientists can use the results of extensive experiments designed to test hypotheses to construct a theory that unifies their findings.
The Inductive Model

10. Explain the deductive model of formulating a hypothesis.
Deduction is reasoning from general principles to specific predictions. This approach is used to test the assumptions of a theory.
The Deductive Model

11. How can researchers combine induction and deduction?
Develop propositions using induction by examining specific cases. Then, make predictions using deduction.
Walster et al. formulated equity theory based on specific observations (induction) and then tested predictions from this theory (deduction).
Combining Induction and Deduction

12. What is the most useful way to develop a hypothesis?
Review research that has already been published. Both experimental and nonexperimental studies can prove helpful.
Building on Prior Research

13. How does a review of prior experiments help us develop a hypothesis?
A review of prior experiments helps in five ways:
Identifies questions that have not been conclusively answered or addressed at all
Suggests new hypotheses
Identifies additional variables that could mediate an effect
Building on Prior Research

14. How does a review of prior experiments help us develop a hypothesis?
Identifies problems other researchers have experienced
Helps avoid duplication of prior research when replication is not intended
Building on Prior Research

15. How does serendipity help develop fruitful hypotheses?
A scientist who is open to unexpected results and who is sufficiently informed can understand the significance of unexpected findings.
However, a dogmatic scientist would be less likely to “see” or appreciate the significance of serendipitous events.
Serendipity and the Windfall Hypothesis

16. What is intuition?
Intuition is knowing without reasoning, or unconscious problem-solving. Intuition guides what we choose to study in an experiment.
Intuition must be directed by our literature review.
Intuition

17. What are helpful strategies for developing experimental hypotheses?
Three promising strategies are:
(1) Read an issue of a psychology journal
(2) Observe how people behave in public places
(3) Choose a real-world problem and try to identify its cause.
When All Else Fails

18. What is the purpose of the Introduction section of an APA-format paper?
The Introduction section provides a selective review of research findings related to the research hypothesis.
This section identifies which questions have not been definitively answered by previous studies and helps show how your experiment advances knowledge in this area.
Searching the Research Literature

19. Explain the value of a meta-analysis?
A meta-analysis can provide helpful information about your topic. A meta-analysis is not an experiment, but rather a statistical analysis of many similar studies.
Searching the Research Literature

20. Explain the value of a meta-analysis?
A meta-analysis measures the average effect size of an independent variable across studies that share similar methodologies. This statistical procedure helps establish the strength and external validity of a causal relationship.
Searching the Research Literature