Executive Function
Thought Suppression Task
Also called: white bear task, white bear paradigm, white bear experiment, thought suppression paradigm, ironic effects of thought suppression
Try not to think of a white bear: people press each time the thought comes, before, during and after trying. Measures reported thoughts and their rebound.
11-13 minUntimed
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
- 7
- Evidence grade
- C
- Registered clinical studies
- 1
What it measures
Asks people to try not to think of a white bear. Over three quiet periods, before, during and after trying, they press each time the thought comes. Every count is the person's own report.
Constructs
- Thought suppression
- Mental control
- Intrusive thoughts
- Self-report of thoughts
Research uses
- Research on mental control and intrusive thoughts
- Research on worry and rumination
- Research on the ironic effects of trying not to think
How the paradigm works
The Thought Suppression Task asks what happens when people try to keep a thought out of mind. In the first experiment of this kind (Wegner, Schneider, Carter and White 1987), people spoke their stream of thought aloud and rang a bell when a white bear came to mind. Told to try not to think of one, they still reported it more than once a minute, and they reported it more often afterward than people who had been asked to think of it from the start.
More about the paradigm
This version runs three quiet periods in a fixed order: free thinking, trying not to think of a white bear, then free thinking again. The standard length is 3 minutes each, set before the session; a setting allows 1 to 5 minutes for the suppression period and for the free-thinking periods. In all three, the person presses the space bar, or taps one large button on a touch screen, each time they think of a white bear or the words come to mind. Only the time of each press is saved: nothing is spoken and no microphone is used. The screen shows the same short reminder throughout and never names the thought, so the screen is not itself a reminder. Two questions at the end ask how hard the person tried and how often they reported the thought. In a control group, the middle period is free thinking too.
The main score is the press rate during the suppression period, in presses per minute with the page on view. The rebound effect is the rate after that period minus the rate before it, the within-person form of the rebound (Wang, Hagger and Chatzisarantis 2020). All of these are the person's own reports. The screen cannot see a thought, so a low count can mean few thoughts or few reports, and the scores describe what was reported. Counts can rise in a later period with no suppression at all, so a study that wants to claim a rebound should compare a suppression group with a control group. Rebound effects are small across studies (d = 0.19 in Wang and colleagues 2020), and instructions that merely allow the thought may show less of it than instructions to think of it (Merckelbach and colleagues 1991; Rassin and colleagues 2005), so scores are best used to compare groups. Scores support research and do not diagnose.
Scores
- Press Rate During Suppressionscore
- Presses per minute in the middle period, where the person tried not to think of a white bear; free thinking in a control group. The person's own report.
- Higher means the person reported the thought more often while trying not to have it
- Rebound Effectscore
- Press rate after the middle period minus the rate before it. The person's own report.
- Positive means more reports after than before; compare with a control group
- Change During Suppressionscore
- Press rate in the middle period minus the rate before it. The person's own report.
- Negative means fewer reports while trying than before
- Press Rate Beforescore
- Presses per minute in the first free-thinking period.
- The person's reported baseline
- Press Rate Afterscore
- Presses per minute in the last free-thinking period.
- Reported thoughts after the middle period
- Presses Beforecount
- Presses counted in the first period.
- Informational
- Presses During Suppressioncount
- Presses counted in the middle period.
- Informational
- Presses Aftercount
- Presses counted in the last period.
- Informational
- Effort Reportedscore
- The person's answer to how hard they tried not to think of a white bear: 1 not at all, 4 very hard. Empty in a control group.
- Shows how the person says they went about it
- Reporting Reportedscore
- The person's answer to how often they reported the thought: 1 almost never, 4 every time.
- Shows how far the person says the counts are complete
- Suppression Period Runflag
- 1 when the middle period asked for suppression, 0 in a control group.
- Informational
- Anticipationscount
- Presses within 100 ms of a period's start or of the last press counted, left out of every count.
- Lower is better
- Periods Completedcount
- Periods that ran to their end.
- Informational
- Time With the Page Hiddenseconds
- Seconds of the periods with the page out of view, when no press could be made.
- Lower is better
Use and evidence
7 papers from 2021 to 2025 name this task in their title or abstract, down 53% compared with 2016 to 2020. That ranks it 465 of 495 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 3 |
| 2024 | 3 |
| 2023 | 0 |
| 2022 | 1 |
| 2021 | 0 |
| 2020 | 3 |
| 2019 | 2 |
| 2018 | 1 |
| 2017 | 5 |
| 2016 | 4 |
| 2015 | 6 |
| 2014 | 3 |
| 2013 | 3 |
| 2012 | 3 |
| 2011 | 4 |
| 2010 | 2 |
| 2009 | 4 |
| 2008 | 2 |
| 2007 | 4 |
| 2006 | 5 |
| 2005 | 8 |
| 2004 | 3 |
| 2003 | 1 |
| 2002 | 1 |
| 2001 | 2 |
| 2000 | 1 |
Use grade E
Fewer than 30 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
- 2
- Papers on reliability or validity
- 8
- Registered clinical studies using it as an outcome
- 1
Note on the counts: the phrases leave out a questionnaire about thought suppression, which is not this task.
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 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Periods
- Three quiet periods in a fixed order: free thinking, trying not to think of a white bear, then free thinking again. Suppression 3 minutes (standard; 1 to 5) and each free-thinking period 3 minutes (standard; 1 to 5), set before the session.
- Report
- The space bar, or one large button on a touch screen, each time the person thinks of a white bear or the words come to mind. The time of each press is saved. The screen shows no count and never names the thought.
- Practice
- 3 presses, each noted on the screen, before the first period. No thought is named in it.
- Control group
- A setting makes the middle period free thinking too, so a study can compare a group that tried with a group that did not.
- Questions
- After the last period: how hard the person tried, and how often they reported the thought, each on 4 steps.
- Scores
- Presses per minute during suppression, the main score; the rebound, presses per minute after suppression minus before it; and the rate and count in each period. Every score is the person's own report.
The screen cannot see a thought, so every score is what the person reported, and a low count can mean few thoughts or few reports. Wegner and colleagues (1987) had people speak their thoughts aloud and ring a bell, and compared groups in two orders. Here nothing is spoken or recorded, and each person is compared with their own first period, the within-person form that Wang and colleagues (2020) describe. Counts can rise in a later period with no suppression, so a study that wants to claim a rebound should run the control group. Rebound effects are small across studies, and instructions that merely allow the thought, as here, may show less of it than instructions to think of it. Compare groups rather than reading one person's score. The scores support research and do not diagnose.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: thought_suppression_period from the scored run, one row per period with the time of each press. The screen cannot see a thought, so no press is right or wrong, accuracy is not judged against chance, and any number of presses is accepted. Fewer periods than planned invalidates. No press in any period, more than 30 presses a minute in a period, the page hidden for at least a tenth of the periods, and an answer at the end that the person did not try or almost never pressed are each flagged for review.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. Every score is the person's own report, so the rule judges only whether the procedure ran and how the presses were given, never what they say about the person. A person may truly have no such thought, so no press at all is only flagged. Time with the page hidden is time in which no press could be made. 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 |
|---|---|---|
| Suppression period (minutes) | 3 | 1 to 5 |
| Free-thinking periods (minutes) | 3 | 1 to 5 |
| Middle period | Try not to think of it (standard) | Try not to think of it (standard), Free thinking (control group) |
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 Thought Suppression Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Wegner, Schneider, Carter & White, 1987), with the standard settings (suppression period (minutes): 3; free-thinking periods (minutes): 3; middle period: Try not to think of it). The main score was press rate during suppression (presses per minute in the middle period, where the person tried not to think of a white bear; free thinking in a control group).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Wegner, D. M., Schneider, D. J., Carter, S. R., & White, T. L. (1987). Paradoxical effects of thought suppression. Journal of Personality and Social Psychology, 53(1), 5-13. https://doi.org/10.1037/0022-3514.53.1.5The white bear task: reporting a thought while trying not to have it, and the rebound after.
- Wang, D., Hagger, M. S., & Chatzisarantis, N. L. D. (2020). Ironic effects of thought suppression: A meta-analysis. Perspectives on Psychological Science, 15(3), 778-793. https://doi.org/10.1177/1745691619898795The within-person form, with baseline, suppression and rebound periods, and the size of the effects.
- Rutledge, P. C., Hancock, R. A., & Rutledge, J. H. (1996). Predictors of thought rebound. Behaviour Research and Therapy, 34(7), 555-562. https://doi.org/10.1016/0005-7967(96)00021-6A within-person study of rebound.
- Merckelbach, H., Muris, P., van den Hout, M., & de Jong, P. (1991). Rebound effects of thought suppression: Instruction-dependent? Behavioural and Cognitive Psychotherapy, 19(3), 225-238. https://doi.org/10.1017/S0141347300013264Instructions that allow the thought, as in the free-thinking periods here.
- Rassin, E., Muris, P., Jong, J., & de Bruin, G. (2005). Summoning white bears or letting them free: The influence of the content of control instructions on target thought frequency. Journal of Psychopathology and Behavioral Assessment, 27(4), 253-258. https://doi.org/10.1007/s10862-005-2405-9How the wording of the comparison period changes reported thoughts.
Source papers
- Wegner DM, Schneider DJ, Carter SR, White TL (1987). Paradoxical effects of thought suppression. Journal of Personality and Social Psychology, 53(1):5-13.Paradigm source
- Wang D, Hagger MS, Chatzisarantis NLD (2020). Ironic effects of thought suppression: A meta-analysis. Perspectives on Psychological Science, 15(3):778-793.Paradigm source
Questions
How long does the Thought Suppression Task take?
About 11 to 13 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?
Press Rate During Suppression, Rebound Effect, Change During Suppression, Press Rate Before, Press Rate After, Presses Before, Presses During Suppression, Presses After, Effort Reported, Reporting Reported, Suppression Period Run, Anticipations, Periods Completed and Time With the Page Hidden. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Thought Suppression Task used in research?
7 papers from 2021 to 2025 name it in their title or abstract, down 53% compared with 2016 to 2020. That ranks it 465 of 495 test families in the ConductCognition test census (use grade E). Source: ConductCognition test census 0.22.0, counted 2 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Thought Suppression Task have?
In the published research, 2 papers report its test-retest reliability and 1 registered clinical study uses 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?
Suppression period (minutes) (1 to 5), free-thinking periods (minutes) (1 to 5) and middle period (Try not to think of it (standard), Free thinking (control group)). 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.
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