When you click on the link below, you will be presented with the
experiment setup screen. On this screen will be the variables you can set
to define your condition. Here is a list of the variables and their
Congruent Words (color and word same)
Incongruent Words (color and word different)
XXXX Colored (string of X's
Congruent Reversed (color and word same but word
Incongruent Reversed (color and word different but word
Beginning Congruent (first two letters of the color word then x's
in congruent color)
Beginning Incongruent (first two letters of the color
word then x's in an incongruent color)
End Congruent (two x's then last
letters of word in congruent color)
End Incongruent (two x's then last
letters of word in incongruent color)
Middle Random Congruent (first and last letter in
correct position, the middle in random order in congruent color)
Middle Random Incongruent (same as above but in an
End Random Congruent (first letter in correct
position, rest of letters in random position, in congruent color)
End Random Incongruent (same as above but in an
Beginning Random Congruent (last letter incorrect
position, the rest in random position, in congruent color)
Beginning Random Incongruent (same as above but in
an incongruent color)
Word In Black Background Congruent
Word in Black Background Incongruent.
Colors to Use
Click on the check boxes to have the
colors and the corresponding words used in your experiment.
Respond to What?
Whether the participant is to respond to
the color or the word. (Set automatically and not available in
conditions XXXColored, for partial words, and when the words are not
Number of Words in Condition
The number of words that will be
displayed, from 20 to 200.
The size of the words, from 12 point to
Location of the word
Center, Left, or Right. If the
words are not centered, there is a fixation mark shown and the words are
Distance from Center
If the words are not centered, this is
the distance of the word from the center measured as a proportion of the
distance from the center to the edge of the screen. (0nly visible when
location is other than center).
Size of Background Region
If using a background color the size of
the total experimental screen that is colored. (only visible in proper
Use Prime Flash
A set of parameters that allow a colored
flash to be presented prior to the word. The flash can be congruent or
incongruent to the color of the word or string. You can also set the
duration of the flash.
After you have finished making your settings, press the Done button at the
bottom of the screen. The Stroop experiment screen will then be presented.
Press the button at the top of the page or the space bar to begin the
experiment. First a fixation mark in the middle of the screen will be
presented. It will be removed if the words are presented in the center.
When the word or string of X'x is presented, indicate the color of the stimulus.
You can do this three ways:
press the relevant button at the bottom of the screen.
press the following keys: r for red, g for green, b for blue, y for yellow
press the following keys: a for red, f for green, j for blue and ; for
The stimuli are randomly selected so you might see the same stimulus twice in
a row - there is no break so you might not see it reappear. Just press the
proper key again.
At the end of the experiment, your results will be presented, both average
reaction time and your accuracy. You can also get your trial by trial
results. Closing your results window(s) will take you back to the setup
window so you can run another experiment.