How the N-Back Test Works:
- Squares flash in a 3×3 grid, each showing a colored number
- You must compare the current stimulus with the one that appeared N trials back in the sequence
- Press Space (or click the grid) when there's a match according to your selected match type
- In 2-Back, compare current with 2 trials back; in 3-Back, 3 trials back, etc.
Match Types:
- Color Only: Match color (ignore number and position)
- Number Only: Match number (ignore color and position)
- Color + Number: Match BOTH color AND number (ignore position)
- Position Only: Match grid position (ignore color and number)
- Position + Color: Match position AND color (ignore number)
- Position + Number: Match position AND number (ignore color)
- Position + Color + Number: Match all three features
Important: The square's position on the grid is randomized unless you select a Position mode. Non-position modes test memory for visual features (color/number) independent of spatial location.
Scoring Terms:
- Hit: Correctly pressed when there was a match
- Miss: Failed to press when there was a match
- False Alarm: Pressed when there was no match
- Correct Rejection: Correctly withheld response when there was no match
- Premature: Pressed during the blank interval between stimuli
Target Accuracy is calculated as Hits / (Hits + Misses). This measures how well you detected actual matches.
Avg Response Time shows the average reaction time for correct hits only (false alarms are not included).
Performance Rating considers your accuracy, false alarm rate, and premature responses to give an overall assessment.
History: Recent sessions are numbered newest-first (Session 1 = most recent). Sessions with zero targets are not saved.