“A paper by Anne Cleary, Anthony Ryals, and Jason Nomi in the December, 2009 issue of Psychonomic Bulletin and Review suggests one factor that leads to the experience of déjà vu. They had people study a number of drawings of scenes. Later, they were shown a number of new scenes and were asked whether they had seen them before. Some of those new scenes had a similar configuration to ones they had studied earlier, but all of the objects were different. For example, during the first phase of the experiment, people might have seen an alley between a fence and a building. Later, they might have seen an alley between a train station and a train. In this case, people often felt that the new scene was familiar, and participants often reported a strong feeling that they had seen the new scene before.”
(Source: psych-facts, via yanilavigne)