“…For example, when a target letter is flanked in irrelevant locations by instances of a letter from the same set, responses typicaIly are faster when the flanker and target identities correspond in terms of the response that each indicates than when they do not (see, e.g., Eriksen & Eriksen, 1974). This effect, known as the Eriksen flanker effect, has been shown to persist with little change in magnitude across four sessions of approximately 300 trials each (Proctor & Fober, 1988). Also, the Stroop effect for color naming, in which naming of the ink color ofa form is slowed when the form speIls an irrelevant color word, has been shown to decrease with practice but not to disappear (see, e.g., Clawson et aI., 1995;Stroop, 1935Stroop, /1992, as has a version of the Stroop effect in which reading location words (left, right, up, down) was slowed when they were printed inside irrelevant arrows that pointed in conflicting directions (Shor, Hatch, Hudson, Landrigan, & Shaffer, 1972).…”