SKILLED PERFORMANCE, PRACTICE, AND THE DIFFERENTIATION OF SPEED-UP FROM AUTOMATIZATION EFFECTS - EVIDENCE FROM 2ND-LANGUAGE WORD RECOGNITION

Practice on cognitive tasks, in general, and word recognition tasks, i n particular, will usually lead to faster and more stable responding. We present an analysis of the relationship between observed reductions in performance latency and latency variability with respect to whethe r processing has merely become faster across the board or whether a qu alitative change, such as automatization, has taken place. The coeffic ient of variability (CV) - the standard deviation of response time div ided by the mean latency - is shown to be useful for this purpose. A c ognitive interpretation of the CV is given that relates it to issues o f skill development. Data from second language learners' word recognit ion performance and from a simple detection task are presented which c onfirm predictions drawn from this interpretation of the cognitive sig nificance of the CV. Initial improvement in a second language word rec ognition task was interpreted as involving more efficient controlled p rocessing, which later gave way to automatization. The implications of this index of skill are discussed in relation to second language deve lopment and the general issue of automaticity of processing components in cognitive skills.