This study investigated the effects of interface tools and learner cognitive styles on performance in searches for information within a hypermedia database. The subjects, 75 students in a university English as a Second Language (ESL) program, were blocked for field dependence and assigned to four treatments which differed by the search tool available. The subjects searched "EarthQuest," a social studies and science hypermedia database, for facts to answer practice and posttest questions on science topics. Field-independent subjects had significantly better achievement than field-dependent subjects in both the index/find and map treatments but not in the browser or all tools treatments. The active engagement, transfer of concepts to new contexts, and high information processing demands that accompany effective use of the index, find, and map tools may explain the greater achievement by field independents. The interface design and instructional use of hypermedia databases should reflect the range of cognitive styles of users. (Contains 20 references.) (Author/JLB)