Chapter 1. What Are IV and DV?

1.1 Introduction

Cognitive Tool Kit
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What are IV and DV ?

What does the word “experiment” mean to you? To experiment is to change something and see what happens. To experiment with a recipe is to add or remove an ingredient and see how it alters the taste. To experiment with clothing might be to combine colors or styles in a way you haven’t before and see how they look. Even in a scientific experiment, you manipulate or change something and see what happens. Anything that can change is called a variable. For example, people can be of different heights, so height is a variable. The variable you change is called the independent variable or IV. Adding or removing an ingredient is the independent variable in the recipe example. The new color or style is the independent variable in the clothing example. But a scientific experiment is not useful if you can’t see what happens when you change this independent variable, so you measure another variable. The variable you measure to see what happens as a result of manipulating the independent variable is called the dependent variable or DV.

Here is an example of a cognitive psychology experiment studying memory: A researcher is interested in whether longer studying leads to longer retention. So, one group of participants is given a list of words to study for 5 minutes. A second group is given the same list of words but allowed 10 minutes to study the list. For each group, there was a break of 20 minutes before they were asked to write down as many words from the list as they could remember. The independent variable in this experiment is the time the participants were given to study the word list. The dependent variable is the number of words from the list the participants were able to write down correctly.

1.2 Experiment Setup

1.3 Instructions

Instructions

In this exercise, you will conduct three short experiments and then be presented with data. Your job will be to identify the independent and dependent variables in the experiments from the instructions and the data presentation in the quiz at the end of each experiment. These experiments are shortened versions of full experiments that are part of the Cognitive Tool Kit. At least one of these experiments will have two independent variables.

1.4 Experiment

Begin Experiment

1.5 Results

Results

1.6 Quiz

Quiz

Question 1.1

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1
Incorrect.
Correct.
The independent variable is the value that is changed by the experimenter. In this case, this experiment manipulated the match between the color and the word, so this is the independent variable.

Question 1.2

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1
Correct.
Incorrect.
The dependent variable is the value the experimenter collects to indicate how you performed in the experiment. In this case, the most important variable measured was how fast you responded to the images displayed. So the correct answer is reaction time.

Question 1.3

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1
Correct.
Incorrect.
The independent variable is the value that is changed by the experimenter. In this case, this experiment manipulated the delay of the arrow after the letters were removed, so this is the independent variable.

Question 1.4

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1
Correct.
Incorrect.
The dependent variable is the value that the experimenter collects to indicate how you performed in the experiment. In this case, the most important variable measured was how many letters you recalled correctly, which we turned into the percentage correct. So the correct answer is accuracy.

Question 1.5

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1
Correct.
Incorrect.
The independent variable is the value that is changed by the experimenter. In this case, this experiment manipulated the angle of rotation between the two figures, so this is the independent variable.

Question 1.6

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Correct.
Incorrect.
The dependent variable is the value the experimenter collects to indicate how you performed in the experiment. In this case, the most important variable measured was how fast you responded to the images displayed. So the correct answer is reaction time.