N Back working memory task, coded with the help of the Matlab Psychtoolbox. A number of difficulty levels included.

There are two main functions:

n_back_task_full()

n_back_task_training()

In both functions the subject sees a series of colored rectangles and has to decide (by a press of the space button) whether the current rectangle matches the one that was shown N steps before. Number of difficulty levels, and number of color sequences within difficulty level can be specified and a break can be taken after each series.

Several difficulty levels are included (from 2 to 5 steps back) and 8 color series are included per difficulty level. Each color series includes a sequence of 36 + n rectangles. The color series are generated such that within each series there a 12 matches and 12 lures (lures are rectangles which have matching colors to a rectangle before, but with a wrong offset in steps).

The task has been utilized as a collateral to a decision making experiment and shows a robust deterioration of performance across difficulty levels (dprime analysis within subject).

• make background white
• add some explanation to task
• automate generation of sequences (specification of difficulty level, number of items and number of sequences within difficulty level)
• allow for read-in of arbitrary pictures instead of colored rectangles generated by psychtoolbox