Hidden objects have to be searched by opening closed boxes that are shown at different locations on the computer screen. The set size (i.e., number of to be searched boxes) can be varied and different error scores can be computed that are argued to measure specific working memory processes (i.e., the number of within-search and between-search errors). The Box Task also has a developer’s mode in which new stimulus displays can be designed for use in tailored experiments. The Box Task also comes with a standard set of stimulus displays (including practice trials, as well as stimulus displays with 4, 6 and 8 boxes) for which reference data can be used (based on the performance of 185 healthy individuals). The raw data can be analyzed easily and the results of different participant can be aggregated into one spreadsheet for further statistical analyses.