The Characteristics of an Experimental Hypothesis The Inductive Model The Deductive Model Combining...

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

What is a hypothesis?

The Characteristics of an Experimental Hypothesis

A hypothesis is an explanation of a relationship between two or more variables.

What is an experimental hypothesis?

The Characteristics of 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.

What is an nonexperimental hypothesis?

The Characteristics of an Experimental 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.

Why must a hypothesis be a synthetic statement?

The Characteristics of an Experimental Hypothesis

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.

What is testability and why is it important?

The Characteristics of an Experimental Hypothesis

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.

Why should hypotheses be parsimonious?

The Characteristics of an Experimental Hypothesis

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.

Explain the inductive model of formulating a hypothesis.

The Inductive Model

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).

How can we build a theory using induction?

The Inductive Model

Scientists can use the results of extensive experiments designed to test hypotheses to construct a theory that unifies their findings.

Explain the deductive model of formulating a hypothesis.

The Deductive Model

Deduction is reasoning from general principles to specific predictions. This approach is used to test the assumptions of a theory.

How can researchers combine induction and deduction?

Combining 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).

What is the most useful way to develop a hypothesis?

Building on Prior Research

Review research that has already been published. Both experimental and nonexperimental studies can prove helpful.

How does a review of prior experiments help us develop a hypothesis?

Building on Prior Research

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

How does a review of prior experiments help us develop a hypothesis?

Building on Prior Research

Identifies problems other researchers have experienced

Helps avoid duplication of prior research when replication is not intended

How does serendipity help develop fruitful hypotheses?

Serendipity and the Windfall Hypothesis

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.

What is intuition?

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.

What are helpful strategies for developing experimental hypotheses?

When All Else Fails

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.

What is the purpose of the Introduction section of an APA-format paper?

Searching the Research Literature

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.

Explain the value of a meta-analysis?

Searching the Research Literature

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.

Explain the value of a meta-analysis?

Searching the Research Literature

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.