It's a Jungle in There: How Competition and Cooperation in the Brain Shape the Mind by David A. Rosenbaum Page A

performance. The concept is accepted in this field as widely as forces are accepted in physics. For response competition to be completed—for one response rather than another to be finally performed—the alternative response must be inhibited and the selected response must excited (or activated).
    Is there is contradiction between saying, as I did earlier in this chapter, that the bottleneck for attention is in response selection and that response competition can be directly observed? If response selection is where the bottleneck exists, shouldn’t you see perfectly quiet muscles for the hand that’s supposed to stay still?
    The answer depends on what you mean by a response. If you mean muscle movements or electromyographic activity, then it’s incorrect to say that an attentional bottleneck exists for response selection. On the other hand, if by response competition you mean the instrumental outcome of physical movements, then there’s no problem. Battles are waged when decisions must be reached about which outcome should prevail in the external environment. When cars jostle for positions as they approach toll booths, the outcomes they’re vying for are getting through the toll booths before the next cars do. The desire for such victories accounts for the jostling in the approach lanes. Seeing the jostling doesn’t mean there isn’t a bottleneck. There’s a bottleneck, to be sure, as every impatient driver and every impatient passenger knows.
    By this way of thinking, studying jostling for position, whether on the approach to the George Washington Bridge or in the muscles of the two hands of people performing flankers tasks, lays bare the battles that go on prior to response selection. In Chapter 7 , which will be concerned with motor control, I will provide more evidence for this jostling, manifested by the hands, eyes, and other effectors when movements are prepared or performed.
Automaticity
    When people press one button for one stimulus or another button for another stimulus, they generally make their responses based on learning. Over the course of learning, stimulus-response connections become automatic.This has both an upside and a downside. The upside is that if the response that’s called for by a stimulus is the response that’s automatically activated by the stimulus, the response can occur very quickly, with little or no deliberation. The downside is that if the response that’s needed is
not
the one that a stimulus calls for, things can get nasty.
    In this connection, consider the Stroop task. 27 If you’re a participant in a Stroop task, your responsibilities sound innocent enough. You’re told, “When you see a word portrayed in green, yell ‘Green’; when you see a word portrayed in red, yell ‘Red’; and likewise for other colors. Just call out the color of the word’s print.”
    “OK,” you say. “Sounds simple enough. Let’s go.”
    One word after another appears on the screen and you yell out the ink colors without much trouble. “Fox” appears in green and you yell out “green.” “Chair” appears in red and you yell out “red.” “Book” appears in blue and you shout out “blue.” You beam at how quickly you respond, at how clever you are.
    Then “Green” is shown in red. Your color-naming time skyrockets and, to make matters worse, you say something like, “Gree…red!” In another trial, “Blue” is shown in green and, again, not only do you slow down, but you say something screwy like “Bl…green.”
    What causes the problem? To say “red” when you see “Green” requires inhibition of your automatic response. To say “green” when you see “Blue” also takes inner censoring. You need to suppress the automatic response that you’re on the verge of producing. 28
    For this effect to be shown—the Stroop effect, named for the person who invented this task—the participant must be a skilled reader. If the participant doesn’t have the strong