Trial Files
This option gives you complete control over stimulus selection across trials and participants. To enable this, in the stimuli tab of your experiment, select trials > upload_file_when_creating_batch. Then, when you've created a version for this experiment, and are creating a participant batch, it will have an entry for "trial file" corresponding to the relevant task. Here you select a "tsv" (Tab Separated Values) file. See below for details on the format. You can make such a file in a spreadsheet like Microsoft Excel, Google Sheets or LibreOffice Calc, by selecting "export as > TSV" or similar. Another way would be to generate the file in matlab or python (pandas is a useful library for this). Note: this feature currently is not yet fully supported for the Multiple Arrangements task. Contact us if you could use some help generating the file.
Example trials file
These are contents for an example file with 4 columns, the first column is the participant ID and the last 3 columns are for three stimuli. Since there are two unique participant IDs ("a" and "b"), this file would create two participant slots. Both participants will have two trials prepared, with 3 stimuli per trial. The participant ID can correspond to a "token" passed in the entry URL, but if you don't use tokens, it can be any arbitrary value. Make sure that the separator between columns is a TAB not spaces.
a moon star comet
a sun planet nebula
b planet nebula moon
b star sun comet