Overshadowing
A stimulus, when it is presented alone, may exert strong control over a behavior. However, if that stimulus is accompanied by another, then the control by the first stimulus may be reduced or eliminated (overshadowed) by the second stimulus.
For example, I might easily recognize my son by the cowlick in his hair. But, if he starts walking and I recognize him from his distinctive gait (rather than by the cowlick), we would say that control of recognition based on his cowlick was overshadowed by control of recognition based his gait.
Cook & Wilding (1997) have demonstrated what they call the face overshadowing effect (FOE). When participants listened to an utterance, and that utterance was accompanied by the presence of a face, then that utterance was less well remembered than the same utterance when unaccompanied by the face. In other words, the presence of the face overshadowed the utterance.
Cook & Wilding say that FOE contradicts the expectation that person recognition should combine face, voice and other information, rather than these sources interfering with each other. They suggest a possible explanation -- that a face-specific processing system exists and that this system can be dominant under many multiple recognition situations.
Similarly, it might be suggested that in the Stroop interference task that words overshadow color.
The present experiments looks at two possible overshadowing scenarios. The standard Stroop interference task will be compared to the same interference task with a face present and to the same interference task with a block of color present. The experiment is testing to see if facial overshadowing occurs, if color overshadowing occurs, and if facial overshadowing is more powerful than color overshadowing
You will see pages of words printed in color. There will be 30 total pages presented one page at a time. On each page, there will be 20 words. The layout of the words is 4 rows of 5 words per row.
Your task is to say the colors of the words to yourself as fast as you can. If you make a mistake, ignore it, and just continue with the next word. You are being timed for this task, so say the colors as fast as you can. However, make certain you say every color.
Timing begins as soon as a page of words appears. Therefore, immediately after you have read the last word, click the mouse button to stop the timer.
As soon as you click the mouse, a new page will appear. You must start reading those words as quickly as possible (clicking the mouse when you have read the last word).
At times, in addition to the words, there will be a face or a colored rectangle on the page. Ignore the face or rectangle and just say the colors of the words to yourself as fast as you can.
When you have finished all 30 pages, your results will be displayed.
The first page you will see is NOT part of the experiment. It is to allow you to adjust the size of your browser window to fit the experiment. You should be able to see all 20 words, and below the words should be a white rectangle with the words "TEST AREA". You should adjust your window so you can see the full rectangle. When you have made these adjustments, you are ready to begin the experiment. Click anywhere in the browser window to bring up the first experimental page.
This experiment can only be run with the EXPLORER Browser. When you are ready, click on the word START to begin.