The basic experimental task consisted of memorization of a list of consonants followed by positionally probed recall of a single item. Immediately after presentation of a list, a positional probe was presented indicating the serial position (SP) of the requested item. Response latency was the main dependent measure. Previous studies with this paradigm have shown that if many trials are run in close succession, the latency for the most recent SP is smaller than that for the first SP, whereas the reverse is found when trials are given in relative isolation. The hypothesis is tested that this effect reflects a buildup of proactive interference (PI) over successive trials. Subjects received strings of six closely spaced trials, and the effect of successive trials on RT was measured. In line with the common findings on PI in short-term recall, the main effect of PI occurred at the second trial of a string, without any clear effect at later trials. Hence, the relatively strong recency effect as observed with many closely spaced trials seems not to be due to PI but to a more aspeciftc change in resource allocation to the various parts of the list.