This is an input gated version of the classic dual n-back in which two disks – lime and orange – and both audio letters and visually presented numbers – are streamed at the same time.
Depending on the two you are instructed to attend to you ignore the other two.
In the examples shown here, in the upper panel, your task is to attend to the lime disk and audio letters (as instructed), ignoring the orange disk and numbers. The responses for 2-back matches are shown in grey (‘F’ and ‘L’ keys).
In the bottom panel, your task is to attend to the orange disk and the numbers (in the orange disk) – ignoring the lime disk and the audio letters. The matches are shown in grey (‘F’ and ‘L’ keys).