Chapter 1. Stroop Effect

1.1 Introduction

Attention is often defined as the ability to focus on one stimulus while ignoring another. We must select some small fraction of all that is going on around us on which to focus or we would be overwhelmed. You can read this screen and block out the music you are listening to, or listen to your professor and ignore what the students are saying in the row behind you. Selecting one stimulus over another is at the heart of attention. But, are there stimuli that are harder to ignore than others? J. Ridley Stroop (1935) developed a fiendish little task that demonstrates that some abilities cannot be shut off. You have been reading for many years and are probably very good at it. This skill is fundamental to success in college. If a word is presented to you, can you control whether you read that word? Try this experiment to see if you are able to shut off your need to read.

Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18, 643-662.

1.2 Experiment Setup

Figure 1.1

1.3 Instructions

You will need to press the space bar to begin the experiment. At the beginning of a set of trials, a fixation mark will appear. Please look at this mark. After it is removed, you will be presented with a stimulus. Your task will be to name the color of the stimulus as quickly and accurately as possible. You may use either the buttons on the screen or the keyboard to give your responses. The color may be in a word, some other string of letters, or it may be a box. In all cases you are to respond to the color of the word, letters, or box.

KEYBOARD Response - What Response Means

R - Red

G - Green

B - Blue

Y - Yellow

1.4 Experiment

Figure 1.2

1.5 Results

Figure 1.3

1.6 Quiz