UC Riverside

The changed-trace and multiple-trace theories of interference are tested in a set of six experiments. The changed-trace hypothesis attributes interference to a rewriting of an initial memory trace. The multiple-trace hypothesis attributes interference to a competition between separate memory traces. Experiments 1 and 2 replicated the modified recognition test used by Chandler (1989, 1991) and provide support for the changed-trace hypothesis due to the strong evidence of retroactive interference, but lack of evidence for proactive interference. The rest of the experiments modify the basic paradigm by changing the type of stimuli (Experiments 3 and 4 introduce words as stimuli instead of images) and the number of presentations of stimuli (Experiments 5 and 6 increase the number of times the interfering stimuli are shown). These changes resulted in evidence for both proactive and retroactive interference. Proactive interference was found in the experiments that used a modified version of Chandler's methodology, supporting the multiple trace hypothesis. If a memory trace is changed, proactive interference will not occur. The lack of evidence for proactive interference in the original task could be due to a recency effect and a large difference in the strength of the original memory trace as compared to the strength of the memory trace for the interfering information.