It is a popular behavior that people can search for “more information” at will on the web. The “more information” option is one of the most important different characteristics between online and traditional setting. Two experiments were conducted to explore the possible effects on the information processing process when the options of “more information” are provided. Information Display Board (IDB) technique of process tracing research was applied in two experiments. There were 4 improvements to the IDB in this study:1.Subjects could respond consecutively along with more options for “more information”; 2.Two new dependent indexes were defined to IDB: the redundancy rate and repeat rate; 3. In some former domestic IDB design, the cells no longer shut down once they were clicked open, then in this study the cells would be closed as soon as new cells were clicked open. 4. Recorded the number of clicks and click-time of each cell in each board. Subjects were required to make purchase decisions from several USB flash disks and PPT wireless presenters presented on the IDB. The tasks were designed on the computer by the VB software. In Experiment 1, the option of “more information” was presented on one group of the information boards, then was not presented on the other group. Each subject completed two groups of information boards. Six dependent indexes were contrasted between the two groups. 68 undergraduates and graduates in shanghai completed Experiment 1. The results showed:1. over half of subjects chose to see more information; 2. the search time and depth reduced significantly when they had the choice for more information; 3. there was significant interaction between “whether can choose for more information or not” and the product type on the depth of search. Subjects who chose “more information” in Experiment 1 needed continue to complete the Experiment 2. The original board (stage 1, 4×7 matrix) in Experiment 1 would add either more products or more properties of products according to subjects’ choice. The new boards were formed (stage 2, 4×14 matrix or 8×7 matrix) in which subjects also could make decision immediately or choose to see more information, forming the ultimate boards (stage 3, 8×14 matrix). Subject must make the final decision on the ultimate board. 64 subjects completed Experiment 2. Choice behaviors were recorded separately in the three stages. The effects of search stage, product type, and choice route(4×7to4×14to8×14 or 4×7to8×7to8×14 ) on dependent indexes were analysed by MANOVA in SPSS. The results showed: 1.over 50% subjects demanded more information in each stage. 2. the average of repeat rate was about 32%; 3.search stage had main effect on number of clicks, time of search, depth of search, compensation index, and redundancy rate;4. there was significant interaction between search stage and choose route on variability of search. These results suggest that the information processing processes would be more selective when more information can be available.