Working Memory
Spatial N-Back Task
Also called: location n-back, visuospatial n-back, spatial 1-back and 2-back
Measure working-memory updating for places: a square moves among eight places, and participants press when it returns to where it was one or two squares back.
9-11 minTimed: desktop or laptop with a mouse or trackpad
Free to start: 10 free participants per account, then $0.99 per participant for academic research, or any yearly plan. Preview any test free after you sign up.
- Papers, 2021 to 2025
- 32
- Evidence grade
- C
- Registered clinical studies
- 15
What it measures
Measures working memory updating for places. A square appears in one of eight places, one every 3 seconds, and participants press the spacebar when it is in the same place as the square 1 or 2 back, at levels fixed before the session.
Constructs
- Working memory updating
- Spatial working memory
- Interference control
- Sustained attention
Research uses
- Working memory research in aging and neurological conditions
- Brain imaging and EEG studies of working memory load
- Within-study comparison of memory load effects
How the paradigm works
The spatial n-back task measures working memory updating for places: keeping track of where things were as new ones arrive. A white square appears in one of eight places around a cross, one square every 3 seconds, each for half a second. The participant presses the spacebar when the square is in the same place as the one n squares back: the one just before it at 1-back, two before it at 2-back. Every other square needs no press.
More about the paradigm
The n-back began with Kirchner (1958) and became one of the most used working memory tasks in brain imaging, where tracking locations is one of its main forms (Carlson et al. 1998; Owen et al. 2005). The timing and blocks here follow Jaeggi and colleagues (2010): each square shows for 500 ms, the next one starts 3 seconds after it, a press counts from the square's start until the next square, and each block has 20 + n squares with 6 matches. The standard session runs 1-back and then 2-back, three blocks each, and each level starts with a short practice with feedback after every square. A setting adds 3-back and another sets two to four blocks at each level. The levels are fixed before the session and never change with performance.
Every block is drawn from the session's seed. Matches fall at random places after the first n squares, and no other square is in the same place as the one n back. A square that repeats the place of a square 1 to 3 back at another distance (a lure) is not controlled; each one is recorded, and their false alarm rate is reported, because lures draw extra false alarms, most of all in older adults (Schmiedek, Li and Lindenberger 2009).
The main score is d-prime at 2-back: how well matches are told apart from other squares, from hits and false alarms with the log-linear correction (Hautus 1995). Each level also gets its hit rate, false alarm rate, d-prime and median response time to matches. Misses and false alarms are reported apart, as Meule (2017) recommends, because the two kinds of error have different correlates. The drop in d-prime from 1-back to 2-back, the lure false alarm rate and anticipations (presses under 100 ms) are also given. N-back scores correlate only weakly with complex span scores (Kane et al. 2007; Redick and Lindsey 2013), so the two kinds of task are not interchangeable. Scores support research and do not diagnose.
Scores
- 2-Back d-Primed'
- Sensitivity on the 2-back blocks: z(hit rate) minus z(false alarm rate), each rate with the log-linear correction.
- Higher is better
- 1-Back d-Primed'
- The same on the 1-back blocks.
- Higher is better
- 3-Back d-Primed'
- The same on the 3-back blocks, when the setting runs them.
- Higher is better
- 2-Back Hit Rate%
- Matches pressed for at 2-back, out of all 2-back matches.
- Higher is better
- 2-Back False Alarm Rate%
- Other squares pressed for at 2-back, out of all other 2-back squares.
- Lower is better
- 2-Back Median Hit Timems
- Median time from a 2-back match's start to the press.
- Lower is faster
- 2-Back Hitscount
- Matches pressed for at 2-back.
- Higher is better
- 2-Back False Alarmscount
- Other squares pressed for at 2-back.
- Lower is better
- 1-Back Hit Rate%
- Matches pressed for at 1-back, out of all 1-back matches.
- Higher is better
- 1-Back False Alarm Rate%
- Other squares pressed for at 1-back, out of all other 1-back squares.
- Lower is better
- 1-Back Median Hit Timems
- Median time from a 1-back match's start to the press.
- Lower is faster
- 1-Back Hitscount
- Matches pressed for at 1-back.
- Higher is better
- 1-Back False Alarmscount
- Other squares pressed for at 1-back.
- Lower is better
- d-Prime Dropd'
- 1-back d-prime minus 2-back d-prime: the cost of the added load.
- Informational
- Lure False Alarm Rate%
- Presses on squares that repeat the place of a square 1 to 3 back at a distance other than n, out of those squares.
- Lower is better
- Missescount
- Matches with no press at or after 100 ms, at every level.
- Lower is better
- Anticipationscount
- Presses under 100 ms after a square appeared, counted as neither hits nor false alarms.
- Lower is better
- Squares Showntrials
- Test squares recorded in the scored run.
- Under 90% of the planned squares is invalid
Use and evidence
32 papers from 2021 to 2025 name this task in their title or abstract, down 6% compared with 2016 to 2020. That ranks it 294 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 8 |
| 2024 | 3 |
| 2023 | 7 |
| 2022 | 8 |
| 2021 | 6 |
| 2020 | 3 |
| 2019 | 4 |
| 2018 | 7 |
| 2017 | 11 |
| 2016 | 9 |
| 2015 | 5 |
| 2014 | 4 |
| 2013 | 2 |
| 2012 | 8 |
| 2011 | 5 |
| 2010 | 4 |
| 2009 | 2 |
| 2008 | 4 |
| 2007 | 1 |
| 2006 | 2 |
| 2005 | 6 |
| 2004 | 2 |
| 2003 | 3 |
| 2002 | 3 |
| 2001 | 0 |
| 2000 | 1 |
Use grade D
30 to 99 papers from 2021 to 2025.
Evidence grade C
At least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies.
- Papers on test-retest reliability
- 0
- Papers on reliability or validity
- 7
- Registered clinical studies using it as an outcome
- 15
How the grades work
Use: A is 1,000 or more papers from 2021 to 2025, B 300 to 999, C 100 to 299, D 30 to 99 and E fewer than 30. Evidence: A means at least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome; B, at least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers; C, at least 2 test-retest papers, 30 reliability or validity papers or 3 registered clinical studies; D, little published measurement evidence found. The counts measure use. They include every paper that names the task in its title or abstract. Grades describe the published research on this task, not ConductCognition's version of it.
Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Places
- Eight places around a central cross, the outer cells of a 3 by 3 grid drawn by code. One white square at a time.
- Timing
- Each square for 500 ms; the next square starts 3,000 ms after it. A press counts from the square's start until the next square and does not end the trial.
- Rule
- Press the spacebar when the square is in the same place as the one n squares back; nothing otherwise.
- Levels
- 1-back, then 2-back (standard; 3-back added as a setting), in that order. Levels are fixed before the session and never change with performance.
- Blocks
- Three blocks at each level (standard; two to four), each of 20 + n squares with 6 matches at seeded places after the first n squares.
- Practice
- 10 + n squares with 3 matches before each level, each followed by 800 ms of feedback. Each test block ends with the share of matches pressed for.
- Score
- 2-back d-prime, from hits and false alarms with the log-linear correction. Hit and false alarm rates, d-prime and median hit time at each level, the drop from 1-back to 2-back and lure false alarms.
Squares that repeat a place at a distance other than n are not controlled; each is recorded. Presses under 100 ms count as anticipations, neither hits nor false alarms.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: spatial_nback_test from the scored run, press when the square is in the same place as n squares back (6 of every 20 + n) and withhold otherwise, at every level run. Fewer than 90% of the planned squares invalidates. Responding mainly on non-matches invalidates; not separating matches is flagged. Missed matches are the measure: only a run of misses covering half the matches (minimum 8) is flagged and withholds the percentile. Responses under 100 ms follow the timed-test rule.
Why these rules
The hit rate is half of d-prime, the primary measure. Responses concentrated on trials that needed none (one-sided Fisher exact test, p < .05) mean the instructions were reversed and invalidate; responses that do not separate the two trial types are flagged. Missed targets are what this test measures, so missed responses never invalidate on their own. A session with no responses is invalid. An unbroken run of misses covering at least half the response trials (minimum 8) may mean the participant stopped, so the session is flagged and its percentile withheld. Responses under 100 ms follow the timed-test rule. The 90% completion limit is a ConductScience choice.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Highest n-back level | 2 | 2 to 3 |
| Blocks at each level | 3 | 2 to 4 |
Yearly plans can change settings within these limits. Free and pay-as-you-go studies use the standard settings.
Need a setting this test does not have?
Devices and languages
- Timed test: participants need a desktop or laptop with a mouse or trackpad. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Spatial N-Back Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Kirchner, 1958; Jaeggi et al., 2010), with the standard settings (highest n-back level: 2; blocks at each level: 3). The main score was 2-back d-prime (sensitivity on the 2-back blocks: z(hit rate) minus z(false alarm rate), each rate with the log-linear correction).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Kirchner, W. K. (1958). Age differences in short-term retention of rapidly changing information. Journal of Experimental Psychology, 55(4), 352-358. https://doi.org/10.1037/h0043688The n-back task.
- Jaeggi, S. M., Studer-Luethi, B., Buschkuehl, M., Su, Y.-F., Jonides, J., & Perrig, W. J. (2010). The relationship between n-back performance and matrix reasoning: Implications for training and transfer. Intelligence, 38(6), 625-635. https://doi.org/10.1016/j.intell.2010.09.001500 ms items 3 seconds apart, a press window to the next item, blocks of 20 + n with 6 matches, three blocks per level.
- Carlson, S., Martinkauppi, S., Rämä, P., Salli, E., Korvenoja, A., & Aronen, H. J. (1998). Distribution of cortical activation during visuospatial n-back tasks as revealed by functional magnetic resonance imaging. Cerebral Cortex, 8(8), 743-752. https://doi.org/10.1093/cercor/8.8.743A visuospatial n-back at increasing loads.
- Owen, A. M., McMillan, K. M., Laird, A. R., & Bullmore, E. (2005). N-back working memory paradigm: A meta-analysis of normative functional neuroimaging studies. Human Brain Mapping, 25(1), 46-59. https://doi.org/10.1002/hbm.20131Location monitoring as one of the main forms of the n-back.
- Schmiedek, F., Li, S.-C., & Lindenberger, U. (2009). Interference and facilitation in spatial working memory: Age-associated differences in lure effects in the n-back paradigm. Psychology and Aging, 24(1), 203-210. https://doi.org/10.1037/a0014685Lures draw extra false alarms, most of all in older adults.
- Hautus, M. J. (1995). Corrections for extreme proportions and their biasing effects on estimated values of d'. Behavior Research Methods, Instruments, & Computers, 27(1), 46-51. https://doi.org/10.3758/BF03203619The log-linear correction.
- Meule, A. (2017). Reporting and interpreting working memory performance in n-back tasks. Frontiers in Psychology, 8, 352. https://doi.org/10.3389/fpsyg.2017.00352Reporting misses and false alarms separately.
- Redick, T. S., & Lindsey, D. R. B. (2013). Complex span and n-back measures of working memory: A meta-analysis. Psychonomic Bulletin & Review, 20(6), 1102-1113. https://doi.org/10.3758/s13423-013-0453-9N-back and complex span scores correlate weakly.
Source papers
- Jaeggi SM, Studer-Luethi B, Buschkuehl M, Su YF, Jonides J, Perrig WJ (2010). The relationship between n-back performance and matrix reasoning: implications for training and transfer. Intelligence, 38(6):625-635.Paradigm source, Young adults
- Owen AM, McMillan KM, Laird AR, Bullmore E (2005). N-back working memory paradigm: a meta-analysis of normative functional neuroimaging studies. Human Brain Mapping, 25(1):46-59.Paradigm source, Adults
Questions
How long does the Spatial N-Back Task take?
About 9 to 11 minutes, as listed in the test library.
What device does a participant need?
Timed test: participants need a desktop or laptop with a mouse or trackpad. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
2-Back d-Prime, 1-Back d-Prime, 3-Back d-Prime, 2-Back Hit Rate, 2-Back False Alarm Rate, 2-Back Median Hit Time, 2-Back Hits, 2-Back False Alarms, 1-Back Hit Rate, 1-Back False Alarm Rate, 1-Back Median Hit Time, 1-Back Hits, 1-Back False Alarms, d-Prime Drop, Lure False Alarm Rate, Misses, Anticipations and Squares Shown. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Spatial N-Back Task used in research?
32 papers from 2021 to 2025 name it in their title or abstract, down 6% compared with 2016 to 2020. That ranks it 294 of 395 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Spatial N-Back Task have?
In the published research, 0 papers report its test-retest reliability and 15 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Which settings can a researcher change?
Highest n-back level (2 to 3) and blocks at each level (2 to 4). Settings can be changed on yearly plans; free and pay-as-you-go studies use the standard settings.
Which languages can participants use?
Participants can take this test in English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese. English is on every plan, and the other languages come with yearly plans. Have a native speaker read the machine-translated text before launch.
Is this a clinical test?
No. ConductCognition is for research use only. It runs, scores and exports the test; clinical interpretation is outside the platform.
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