involved in response evaluation—deciding whether the answer is correct or incorrect. Activity in this region increases when the probability of an error is higher. Theories There are several theories used to explain the Stroop effect, which are commonly known as "race models". This is based on the underlying notion that both relevant and irrelevant information are processed in parallel, but that they "race" to enter the single central processor during response selection. They are: Processing speed This theory, also called Relative Speed of Processing Theory, suggests there is a lag in the brain's ability to recognize the color of the word since the brain reads words faster than it recognizes colors. This is based on the idea that word processing is significantly faster than color processing. In a condition where there is a conflict regarding words and colors (e.g., Stroop test), if the task is to report the color, the word information arrives at the decision-making stage before the color information which presents processing confusion. Conversely, if the task is to report the word, because color information lags after word information, a decision can be made ahead of the conflicting information. Selective attention The Selective Attention Theory suggests that color recognition, as opposed to reading a word, requires more attention. The brain needs to use more attention to recognize a color than to encode a word, so it takes a little longer. The responses lend much to the interference noted in the Stroop task. This may be a result of either an allocation of attention to the responses or to a greater inhibition of distractors that are not appropriate responses. Automaticity This theory is the most common theory of the Stroop effect. It suggests that since recognizing colors is not an "automatic process" there is hesitancy to respond, whereas, in contrast, the brain automatically understands the meanings of words as a result of habitual reading. This idea is based on the premise that automatic reading does not need controlled attention, but still uses enough attentional resources to reduce the amount of attention accessible for color information processing. Stirling (1979) introduced the concept of response automaticity. He demonstrated that changing the responses from colored words to letters that were not part of the colored words increased reaction time while reducing Stroop interference. Parallel distributed processing This theory suggests that as the brain analyzes information, different and specific pathways are developed for