The effect of verbal labeling in a serial position short term memory task was investigated. Forty female college students were given 16 trials each. Eight trials involved only central items which had to be recalled. The other eight trials involved both central and incidental items. Half of the subjects verbalized the names of the central items as they were presented. Verbalization was found to decrease short term memory performance. There was no effect of one versus two stimuli per card. The authors feel that these results supplement the past research in this area and support a view that with age the use of rehearsal strategies becomes increasingly dominant. Consequently, labeling inhibits the use of more efficient processing. This paper comprises a report in "Development of Language Functions, a Research Program-Project (Study M: Development of Selective Attention Abilities)." (DO)