We investigated how the design of the query interface impacts stress, workload and performance during information search. Two query interfaces were used: a standard interface which looks similar to contemporary, general purpose search engines with a standard query box, and an experimental (structured) interface that was designed to slow people down when querying by presenting a series of boxes for query terms. We conducted a between subjects laboratory experiment where participants were randomly assigned to use one of the query interfaces to complete two assigned search tasks. Stress was measured by recording physiological signals and with the Short Stress State Questionnaire. Workload was measured with the NASA-TLX and log data was used to characterize search behavior. The differences in stress and search behaviors were not significant, but participants who used the structured interface rated their success significantly higher than those who used the standard interface, and reported significantly less workload.