Stimulus interaction and between-trials proactive interference in monkeys.

Most theoretical accounts of proactive interference in delayed-matching-to-sample paradigms focus on processes linked to time. Two experiments questioned this exclusive focus on temporal facts. Between-trials proactive interference was studied in a situation in which the similarity of consecutive trials was varied along the dimensions of color, form, and position. All of these factors as well as the similarity of sample and test contexts contributed to memory performance. A mathematical model based on the assumptions that similarity strongly influences memory-based judgements and that overall similarity is determined by the multiplicative interaction of component dimensions gave an excellent qualitative and quantitative account of the data in both experiments. These results support a broader view of factors determining proactive interference and are inconsistent with the idea that these multiple factors can be treated as independent.