Effects of centrality on retrieval of text-based concepts.

Four experiments examined the effect of centrality on retrieval time using a wide range of testing conditions. Subjects read passages containing concepts that were rated as central, moderately central, or peripheral to a passage, and then were asked to retrieve those concepts. Experiment 1 used a probe recognition task that contained foils that were unrelated to the passage, and it was found that central concepts were recognized more quickly than peripheral concepts. In Experiment 2, the foils were passage related, resulting in a much larger recognition advantage of central concepts over peripheral concepts. Experiment 3 used a speeded-recall task. Again central concepts were recalled more quickly than less central concepts. Experiment 4 ruled out a simple strength argument. The results of all four experiments are discussed in terms of text being represented as an integrated network. Within this network, central concepts are more interconnected, providing additional access routes that facilitate retrieval.