Episodic Memory
Think and No-Think Task
Also called: think/no-think paradigm, TNT task, retrieval suppression task, suppression-induced forgetting task
Measure memory suppression: picture pairs, cues to recall or keep a partner out of mind, and a final test of every pair.
15-19 minUntimed
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
- 81
- Evidence grade
- C
- Registered clinical studies
- 6
What it measures
Measures memory suppression. Participants learn picture pairs, then see one picture of a pair and either bring its partner to mind or keep it out of mind; a final test compares memory for the suppressed pairs with pairs left alone.
Constructs
- Memory suppression
- Inhibitory control of memory
- Episodic memory
- Intrusive memories
Research uses
- Research on intrusive memories in anxiety, depression and post-traumatic stress
- Research on memory control across the lifespan
- Individual-difference studies of inhibitory control
How the paradigm works
The Think and No-Think Task measures memory suppression: whether repeatedly keeping a memory out of mind makes it harder to recall later. Participants learn pairs of pictures. They then see the first picture of some pairs again and again, in a colored frame. A green frame means bring the partner picture to mind; a red frame means keep the partner out of mind, without looking away and without thinking of something else instead. A third set of pairs is learned but never shown in between, and serves as the baseline.
More about the paradigm
The task follows Anderson and Green (2001) and the standard procedure of Nardo and Anderson (2024), with picture pairs. Each pair is studied for 3 seconds. In test-feedback cycles, the participant says whether they remember each partner, picks it from four pictures if they do, and then sees the pair again; the cycles repeat, up to three, until half the pairs are recalled in one cycle. In the think and no-think part each cue shows for 3 seconds, followed by a report of whether its partner came to mind: never, briefly or often (Levy and Anderson 2012). Each cue appears 8 times, adjustable to 12, twice per block, with a rest between blocks. The final test asks about every pair, the baseline pairs included, with no feedback; the instructions now ask for every partner, red-frame pairs too. One question at the end asks whether the participant brought a red-frame partner to mind on purpose. The standard has 6 pairs in each condition; a setting gives up to 8. The session takes about 15 to 19 minutes.
The pictures are 52 emoji from Noto Emoji, everyday objects and animals that no other test in the library shows, joined into 26 pairs of unrelated things by a stated rule: 24 pairs in three sets of 8 and 2 practice pairs. Each session gives the three sets the Think, No-Think and Baseline roles by one of three rotations, so every set serves in every condition. A pair counts as recalled when the participant says they remember the partner and then picks it from four partners of the same condition.
The main score is suppression-induced forgetting: baseline recall minus no-think recall. Recall in each condition, the same scores over the pairs learned before the think and no-think part, and the intrusion reports (how often a no-think partner came to mind, and how fast that declined) are also reported. With the original cues, no-think pairs are typically recalled about 8 percentage points less often than baseline pairs, over more than 2,000 young adults in published and laboratory studies (Anderson and Huddleston 2012); an online replication with words found no effect (Wiechert et al. 2023). Group comparisons are safer than single scores, which rest on 6 to 8 pairs per condition. Scores support research and do not diagnose.
No norms are applied to this task. Suppression-induced forgetting is a difference between conditions with no better direction, so sessions are not ranked against other people. Use the scores for raw analysis and within-study comparison.
Scores
- Suppression-Induced Forgetting%
- Share of baseline pairs recalled minus share of no-think pairs recalled.
- Positive when suppressed pairs were recalled less often; no better direction
- Retrieval Facilitation%
- Share of think pairs recalled minus share of baseline pairs recalled.
- Positive when pairs recalled during the task were recalled more often later
- Recall, Think%
- Share of think pairs reported as remembered and then chosen correctly in the final test.
- Higher means better memory for these pairs
- Recall, No-Think%
- Share of no-think pairs reported as remembered and then chosen correctly in the final test.
- Lower than baseline means suppression-induced forgetting
- Recall, Baseline%
- Share of baseline pairs reported as remembered and then chosen correctly in the final test.
- The reference for the other conditions
- Suppression-Induced Forgetting, Learned Pairs%
- Baseline minus no-think recall over the pairs recalled in the last learning cycle.
- Positive when suppressed pairs were recalled less often; no better direction
- Remembered Reports%
- Share of final-test pairs whose partner the participant reported remembering.
- Context for the recall scores
- Choice Accuracy%
- Share of choices, made after a remembered report, that picked the right partner of four.
- Higher means the reports were reliable
- Intrusion Rate%
- Share of no-think trials after which the partner was reported to have come to mind briefly or often.
- Lower means better control of unwanted memories
- Intrusion Rate, First Appearance%
- Intrusion rate on each no-think cue's first appearance.
- Starting level of intrusions
- Intrusion Rate, Last Appearance%
- Intrusion rate on each no-think cue's last appearance.
- Final level of intrusions
- Intrusion Slopescore
- Decline in the no-think intrusion rate per block, as a share of the first block's rate (proportionalized slope, sign reversed).
- Positive when intrusions declined over repetitions
- Think Recall During Task%
- Share of think trials after which the partner was reported to have come to mind.
- Close to 1 when think instructions were followed
- Missed Reportscount
- Think and no-think trials with no report within 2 seconds.
- Lower is better
- Learning Recall%
- Share of pairs recalled in the last learning cycle, before the think and no-think part.
- At least 0.5 meets the learning criterion
- Learning Cyclescount
- Test-feedback cycles run, 1 to 3.
- Informational
- Reported Deliberate Recall0/1
- 1 when the participant said they brought a red-frame partner to mind on purpose.
- 1 makes the suppression score hard to read
- Anticipationscount
- Final-test answers faster than 100 ms; their pairs are left out of every score.
- Lower is better
- Pairs Testedcount
- Pairs in the final test, not counting the two warm-up pairs (18 at the standard settings).
- Informational
Use and evidence
81 papers from 2021 to 2025 name this task in their title or abstract, up 62% compared with 2016 to 2020. That ranks it 203 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 22 |
| 2024 | 17 |
| 2023 | 13 |
| 2022 | 17 |
| 2021 | 12 |
| 2020 | 13 |
| 2019 | 8 |
| 2018 | 10 |
| 2017 | 8 |
| 2016 | 11 |
| 2015 | 13 |
| 2014 | 13 |
| 2013 | 14 |
| 2012 | 17 |
| 2011 | 11 |
| 2010 | 7 |
| 2009 | 15 |
| 2008 | 7 |
| 2007 | 13 |
| 2006 | 9 |
| 2005 | 2 |
| 2004 | 1 |
| 2003 | 0 |
| 2002 | 0 |
| 2001 | 0 |
| 2000 | 0 |
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
- 12
- Registered clinical studies using it as an outcome
- 6
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.
- Pictures
- 52 emoji pictures from Noto Emoji in 26 pairs: 3 sets of 8 pairs and 2 practice pairs. Each session gives the sets the Think, No-Think and Baseline roles by one of 3 rotations.
- Learning
- Each pair studied for 3,000 ms with a 1,000 ms gap (6 pairs per condition, standard; 6 to 8). Then up to 3 test-feedback cycles: say whether you remember the partner, pick it from 4 pictures, then see the pair for 2,000 ms, until half the pairs are recalled in one cycle.
- Think and no-think
- Each Think and No-Think cue 8 times (standard; 8 to 12), 2 per block, for 3,000 ms in a solid green frame (think of the partner) or a dashed red frame (keep it out of mind), after a 500 ms cross. No more than 3 of one condition in a row.
- Reports
- After each cue: did the partner come to mind? Never, briefly or often, within 2,000 ms.
- Final test
- Every pair, Baseline pairs included, after 2 warm-up pairs: say whether you remember the partner, then pick it from 4 partners of the same condition. No time limit and no feedback.
- Practice
- 4 cues without reports, a question on what a red frame asks, then 4 cues with reports.
Most think/no-think studies use words and spoken recall. Here the pairs are pictures and recall is a report checked by a 4-picture choice, so values may differ from published ones.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: think_no_think_test and think_no_think_test_choice from the scored run, one question per critical pair and a four-picture choice after each Yes. Choice accuracy significantly below chance (one-sided exact binomial, p < .05, chance 25%) invalidates; accuracy not above chance over 10 or more choices is flagged. One position on 90% of choices invalidates when accuracy is not above chance. Choices under 200 ms on at least half of 4 or more choices invalidate. No pair reported as remembered invalidates. A learning cycle below the 50% criterion, a reported deliberate recall of a red-frame partner and more than 25% missed reports are flagged; the first two withhold the percentile. A hidden tab withholds the percentile.
Why these rules
The wrong pictures on offer are partners from the same condition, so a guess is right one time in four: Accuracy significantly below chance (one-sided exact test, p < .05) cannot come from guessing; it means the response mapping was reversed or the task was not followed (Slick, Sherman and Iverson 1999 treat below-chance forced-choice performance as definite response bias). Chance-level accuracy can be a real result in impaired participants, so it is only flagged. One option on at least 90% of answered trials, when the correct options are balanced and accuracy is not above chance, means the answers did not depend on the items (the task counterpart of long-string responding in surveys; Curran 2016). The right picture's position is balanced across pairs. An answer under 200 ms is faster than a simple visual reaction, so it cannot reflect the item. Following response-time effort screening for untimed tests (Wise and Kong 2005), the session is invalid only when at least half the answers are that fast. The effect needs pairs that were learned and partners that were kept out of mind (Nardo and Anderson 2024): pairs not learned to the criterion, or partners recalled on purpose, which removes the effect (Anderson and Huddleston 2012), make the score hard to read, so these are flagged. A session with no pair remembered has no recall to compare. The effect itself, which may be zero or negative, is never judged. A hidden tab lets the study, delay or response timers run without the participant, so a percentile is withheld after one.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Pairs per condition | 6 | 6 to 8 |
| Appearances of each cue | 8 | 8 to 12 |
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
- Untimed test: runs on desktops, laptops, tablets and phones. Participant devices
- Languages: English, Spanish, French, German, Italian, Portuguese (Brazil), Chinese (Simplified) and Japanese.
- Available on: Every plan, including the free plan.
- No percentile. Scores and quality flags only. How norms work
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Think and No-Think Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Anderson & Green, 2001), with the standard settings (pairs per condition: 6; appearances of each cue: 8). The main score was suppression-induced forgetting (share of baseline pairs recalled minus share of no-think pairs recalled).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Anderson, M. C., & Green, C. (2001). Suppressing unwanted memories by executive control. Nature, 410(6826), 366-369. https://doi.org/10.1038/35066572
- Nardo, D., & Anderson, M. C. (2024). Everything you ever wanted to know about the Think/No-Think task, but forgot to ask. Behavior Research Methods, 56(4), 3831-3860. https://doi.org/10.3758/s13428-024-02349-9The standard procedure, timing and scores.
- Levy, B. J., & Anderson, M. C. (2012). Purging of memories from conscious awareness tracked in the human brain. Journal of Neuroscience, 32(47), 16785-16794. https://doi.org/10.1523/JNEUROSCI.2640-12.2012The never, briefly or often report and the intrusion slope.
- Gagnepain, P., Henson, R. N., & Anderson, M. C. (2014). Suppressing unwanted memories reduces their unconscious influence via targeted cortical inhibition. Proceedings of the National Academy of Sciences, 111(13), E1310-E1319. https://doi.org/10.1073/pnas.1311468111Picture partners recalled, then confirmed by a choice.
Source papers
- Anderson MC, Green C (2001). Suppressing unwanted memories by executive control. Nature, 410(6826):366-369.Paradigm source, Adults
- Nardo D, Anderson MC (2024). Everything you ever wanted to know about the Think/No-Think task, but forgot to ask. Behavior Research Methods, 56(4):3831-3860.Paradigm source, Adults
- Levy BJ, Anderson MC (2012). Purging of memories from conscious awareness tracked in the human brain. Journal of Neuroscience, 32(47):16785-16794.Paradigm source, Young adults
- Stramaccia DF, Meyer AK, Rischer KM, Fawcett JM, Benoit RG (2021). Memory suppression and its deficiency in psychological disorders: a focused meta-analysis. Journal of Experimental Psychology: General, 150(5):828-850.Paradigm source, Adults
Questions
How long does the Think and No-Think Task take?
About 15 to 19 minutes, as listed in the test library.
What device does a participant need?
Untimed test: runs on desktops, laptops, tablets and phones. The browser must be Chrome, Edge, Firefox or Safari.
What scores does it produce?
Suppression-Induced Forgetting, Retrieval Facilitation, Recall, Think, Recall, No-Think, Recall, Baseline, Suppression-Induced Forgetting, Learned Pairs, Remembered Reports, Choice Accuracy, Intrusion Rate, Intrusion Rate, First Appearance, Intrusion Rate, Last Appearance, Intrusion Slope, Think Recall During Task, Missed Reports, Learning Recall, Learning Cycles, Reported Deliberate Recall, Anticipations and Pairs Tested. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Think and No-Think Task used in research?
81 papers from 2021 to 2025 name it in their title or abstract, up 62% compared with 2016 to 2020. That ranks it 203 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 Think and No-Think Task have?
In the published research, 0 papers report its test-retest reliability and 6 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Does it report a percentile?
No. Scores and quality flags only.
Which settings can a researcher change?
Pairs per condition (6 to 8) and appearances of each cue (8 to 12). 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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