It's a puzzle all right: the hippocampus and food hoarding.

Although evidence for local over-citing is strong, our results do not reveal whether researchers in one region are more to blame than the other. This is because it is impossible to judge what an unbiased rate of citation for European or North American papers should be [5]. For example, if North Americans truly produced better science, the signature of over-citing in that part of the world would be justified, and the European bias would then be a sign of parochial practices (and vice versa). Notwithstanding such a possibility, however, the strength of geographical over-citing still raises concerns that both sides of the Atlantic could be engaging in parochial citation practices. It is particularly alarming that differences do not diminish for older papers that should have had more time to become known by both Americans and Europeans regardless of who originally published the work. Of course, for empirical studies, differences could, to some extent, reflect acceptable patterns of local citing because they concern local natural history. Yet, theoretical papers (defined as no original data presented in the paper) published between 1984 and 2002 showed similar fates (Figure 1d; nZ59 for Ecology, nZ42 for Journal of Animal Ecology). However, in theoretical papers published in Journal of Animal Ecology, significant geographical overciting is, intriguingly, replaced by papers ofEuropean origin being citedmoreby researchers onboth sides of theAtlantic. Our results, together with those reported in [5], suggest