Signaling hierarchical and sequential organization in expository text

Four experiments tested a hypothesized function of signaling devices, namely, to communicate information about text organization. Experiments 1 and 2 compared headings that communicated the hierarchical organization of text topics with headings that did not communicate the hierarchical organization. Signaling organization led to more complete and accurate outlines of a text. Experiment 3 compared headings that communicated the sequential organization of text topics with headings than did not communicate the organization. Signaling organization led to faster text search. Experiment 4 compared headings that emphasized the sequential organization of topics with headings that emphasized their hierarchical organization. In this comparison, sequential headings led to faster search times than hierarchical headings. Together, the results of the four experiments demonstrate (a) that signals can communicate two distinct types of organizational information, and (b) those two types of organization have distinct implications for text processing.