Two-dimensional recall: Immediate identification of clusters in episodic and semantic memory

To show the organization of recall, items that are remembered together can be written on the same line of a two-dimensional (2D) grid. Such 2D recall does not induce the clustering it reveals. Two-dimensional recall on all trials is essentially the same as standard sequential free recall followed by unexpected 2D recall. The clustering in standard free recall is shown by identifying clusters that emerge in 2D recall. Clustering increases until most of recall is clustered. Two-dimensional recall shows that the number of clustered items increases more rapidly than the number of clusters, and that most of the increasing recall during learning is due to the increasing number of extra items recalled as part of a cluster.