Working Memory
2-Back Task
Probe higher-load working-memory updating with a browser-native 2-back task suitable for remote studies.
3-4 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. Try it here first, with no account.
- Papers, 2021 to 2025
- 3,210
- Evidence grade
- A
- Registered clinical studies
- 790
What it measures
Measures working memory by requiring participants to indicate whether the current stimulus matches the one presented N items ago.
Constructs
- Working memory updating
- Executive working memory
- Cognitive load management
- Central executive function
Research uses
- Working memory capacity assessment
- Schizophrenia cognitive profiling
- ADHD working memory evaluation
- Cognitive training outcome measurement
- Aging-related working memory decline
How the paradigm works
The 2-Back task increases working memory demand by requiring participants to detect whether the current letter matches the letter shown two positions back. This higher load requires simultaneous maintenance of two recent items, continuous updating as each new stimulus arrives, and comparison against the item two steps back rather than the immediately preceding one.
More about the paradigm
The 2-Back engages the dorsolateral prefrontal cortex (DLPFC) more strongly than the 1-Back, reflecting the increased executive demands of managing a larger memory buffer. The difference in performance between 1-Back and 2-Back d-prime isolates the cost of increased working memory load, independent of basic sustained attention.
This task is one of the most widely used working memory paradigms in neuroimaging research, with well-established associations to DLPFC activation and sensitivity to working memory deficits across clinical populations.
Scores
- Overall Accuracy%
- Proportion of all trials correctly classified. Typically lower than 1-Back due to increased demand.
- Higher is better
- Hitscount
- Number of 2-back matches correctly identified.
- Higher is better
- Missescount
- Number of 2-back matches missed.
- Lower is better
- False Alarmscount
- Incorrect responses to non-match stimuli.
- Lower is better
- Correct Rejectionscount
- Non-match stimuli correctly ignored.
- Higher is better
- d-Primed'
- Signal detection sensitivity. Primary measure. Expected to be lower than 1-Back d-prime in the same individual.
- Higher is better
- Hit RTms
- Average reaction time on correct 2-back match detections.
- Lower is better
Use and evidence
3,210 papers from 2021 to 2025 name this task in their title or abstract, up 22% compared with 2016 to 2020. That ranks it 6 of 582 test families in our census. The counts cover every version of the task, so the 1-Back Task page shows the same figures. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 832 |
| 2024 | 628 |
| 2023 | 567 |
| 2022 | 586 |
| 2021 | 597 |
| 2020 | 595 |
| 2019 | 530 |
| 2018 | 547 |
| 2017 | 487 |
| 2016 | 472 |
| 2015 | 419 |
| 2014 | 423 |
| 2013 | 393 |
| 2012 | 333 |
| 2011 | 290 |
| 2010 | 256 |
| 2009 | 184 |
| 2008 | 200 |
| 2007 | 152 |
| 2006 | 125 |
| 2005 | 113 |
| 2004 | 108 |
| 2003 | 93 |
| 2002 | 66 |
| 2001 | 71 |
| 2000 | 76 |
Use grade A
1,000 or more papers from 2021 to 2025.
Evidence grade A
At least 25 papers report its test-retest reliability and at least 25 registered clinical studies use it as an outcome.
- Papers on test-retest reliability
- 104
- Papers on reliability or validity
- 649
- Registered clinical studies using it as an outcome
- 790
Measured on ConductCognition
Pooled across the studies that feed our platform norms, by device group. A figure needs 50 or more people.
No pooled figure yet.
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 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: nback_test, press on matches (about 32%) within 1.5 s. No responses at all 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.
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.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Number of trials | 48 | 30 to 80 |
| Target percentage | 0.33 | 0.2 to 0.5 |
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.
Included in these batteries
Each battery runs this test with others in a fixed order, with standard settings.
- Working Memory and Learning Battery4 tests, 19 minutes per participant
Cite and describe
Participants completed the 2-Back Task in a web browser (ConductCognition task version 1.0.1, scoring version 1.0.0; Kirchner, 1958; Jaeggi et al., 2010), with the standard settings (number of trials: 48; target percentage: 0.33). The main score was d-prime (signal detection sensitivity).
Paradigm source: Kirchner (1958); Jaeggi et al. (2010).
ConductCognition versions: task version 1.0.1, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
Source papers
- Bopp KL, Verhaeghen P (2020). Aging and n-back performance: A meta-analysis. Journals of Gerontology: Psychological Sciences, 75(2):229-240.Paradigm source, 18-79
Questions
How long does the 2-Back Task take?
About 3 to 4 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?
Overall Accuracy, Hits, Misses, False Alarms, Correct Rejections, d-Prime and Hit RT. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the 2-Back Task used in research?
3,210 papers from 2021 to 2025 name it in their title or abstract, up 22% compared with 2016 to 2020. That ranks it 6 of 582 test families in the ConductCognition test census (use grade A). Source: ConductCognition test census 0.39.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the 2-Back Task have?
In the published research, 104 papers report its test-retest reliability and 790 registered clinical studies use it as an outcome (evidence grade A in the ConductCognition test census).
Which settings can a researcher change?
Number of trials (30 to 80) and target percentage (0.2 to 0.5). 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.
Every test: the full test list.
Run this test in your next study
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