This study compared the rapid word processing abilities of groups of students in college, fourth grade, second grade, and kindergarten to see if there is a developmental pattern in such skill development, and to see if phonics training should emphasize either letters and the orthographic rules that create words or letter clusters (common words) that are learned as perceptual units through reading experience. Subjects indicated whether a target letter appeared in a display consisting of three, four, or five letter words, pseudowords, and nonwords; the target letter was present in half the trials. The pattern of results obtained for the kindergarten students was different from the results for the other age groups; kindergarten pupils showed no different mean response times for words, pseudowords, or nonwords, while all other groups showed ordered response times that increased from words to pseudowords to nonwords. These results are taken as further evidence of the importance of orthographic regularity and phonics in beginning reading instruction. (Discussion following presentation of the paper is included.) (RL)