Executive Function
Reward and Interest Task
Also called: overjustification effect, undermining effect, free-choice paradigm, stopwatch task
Measure whether points for success change the wish to keep playing. Count the rounds of a stopwatch game people choose to play in free time after rounds with or without points.
7-9 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
- 45
- Evidence grade
- C
- Registered clinical studies
- 0
What it measures
Measures how points for success change the wish to keep playing. Participants stop a stopwatch at 5.00 seconds, with or without points, then have free time in which they may play on for no points, read or wait. The main score is the number of rounds played in the free time.
Constructs
- Intrinsic motivation
- Free-choice persistence
- Reward undermining (overjustification)
- Interest
Research uses
- Motivation research
- Behavioral economics
- Educational psychology
How the paradigm works
A reward for doing a task can change how much a person wants to do it once the reward is gone. Participants play a stopwatch game: a watch starts by itself, and they stop it as close to 5.00 seconds as they can with the space bar or a Stop button. A stop within 50 ms either side is a success. After 3 practice rounds come 20 scored rounds, with 10 points for each success in the points condition and no points in the other. Then 3 minutes of free time follow: participants may play more rounds for no points, read four short articles or wait, and the next part starts by itself. Two ratings of the game, interest and enjoyment on 1 to 6 scales, end the task.
Scores
- Free-Time Roundscount
- Rounds of the game started in the free time after the last block, including one cut short when the free time ended.
- Compare groups or blocks
- Free-Time Playingseconds
- Seconds spent playing in that free time.
- Informational
- Free-Time Readingseconds
- Seconds spent reading the articles in that free time.
- Informational
- Played in Free Time0/1
- 1 when at least one round was played in that free time.
- Informational
- First Free-Time Roundseconds
- Seconds from the start of that free time to the first round; null when none was played.
- Informational
- Baseline Free-Time Roundscount
- With two blocks, rounds played in the free time after the block without points; null with one block.
- Informational
- Change in Free-Time Roundscount
- Free-time rounds after the last block minus those after the first; null with one block. Negative values mean less play after the second block.
- Compare groups
- Interest Ratingscore
- How interesting the game was, from 1 (not at all) to 6 (very).
- Informational
- Enjoyment Ratingscore
- How much playing was enjoyed, from 1 (not at all) to 6 (very much).
- Informational
- Success Rate%
- Share of the last block's rounds stopped within the success window.
- Informational
- Mean Stop Errorms
- Mean distance of the last block's stops from 5.00 seconds.
- Informational
- Points Wonpoints
- Points from successes in rounds with points.
- Informational
- Scored Roundscount
- Scored rounds recorded in all blocks.
- 20 standard
- Watch Ran Outcount
- Scored rounds in which the watch ran to 10 seconds without a stop.
- 0 expected
- Stops Under 100 mscount
- Stops within 100 ms of the watch starting.
- 0 expected
- Check Correct0/1
- 1 when the check question on when a round is a success was answered correctly.
- 1 expected
Use and evidence
45 papers from 2021 to 2025 name this task in their title or abstract, down 26% compared with 2016 to 2020. That ranks it 376 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 11 |
| 2024 | 9 |
| 2023 | 9 |
| 2022 | 9 |
| 2021 | 7 |
| 2020 | 8 |
| 2019 | 13 |
| 2018 | 14 |
| 2017 | 13 |
| 2016 | 13 |
| 2015 | 12 |
| 2014 | 13 |
| 2013 | 8 |
| 2012 | 6 |
| 2011 | 9 |
| 2010 | 12 |
| 2009 | 7 |
| 2008 | 8 |
| 2007 | 5 |
| 2006 | 4 |
| 2005 | 8 |
| 2004 | 6 |
| 2003 | 2 |
| 2002 | 5 |
| 2001 | 3 |
| 2000 | 2 |
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
- 2
- Papers on reliability or validity
- 14
- Registered clinical studies using it as an outcome
- 0
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.
Note on the counts: many papers are workplace and classroom studies.
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 8 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Game
- A stopwatch to stop at 5.00 seconds with the space bar or a Stop button. A stop within 50 ms either side is a success; the window is a setting from 20 to 150 ms.
- Rounds
- 3 practice rounds, then 20 scored rounds (10 to 40). In the points condition each success earns 10 points; in the other, no points.
- Free time
- 3 minutes (1 to 8) after the rounds: play more rounds for no points, read 4 short articles or wait. It ends by itself.
- Designs
- One block compared between study groups, or two blocks: a block without points and its free time, then the chosen condition and its free time.
- Ratings
- Interest and enjoyment of the game on 1 to 6 scales, after the last free time.
- Scores
- Rounds played in the free time (main), seconds playing and reading, the change from the first free time, both ratings and the success rate.
The game, articles and ratings are our own. Points are not exchanged for money unless the study pays for them, and the free time is announced, not hidden. Compare groups or blocks run with the same settings. Scores support research and do not diagnose. No percentile output.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: reward_interest_round from the run with the most rounds, with its free time and ratings. Whether to play in the free time has no correct answer, so neither accuracy nor a repeated choice is judged, and playing no round is a result. A run in which the watch ran out in every round is invalid. A missing free time, missing ratings and a wrong answer to the check question are flagged.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. Free-time play is what a person chooses when nothing is asked of them, so any count, 0 included, can be a real result (Deci, 1971). A run with no stop at all shows no play. Stopping the watch is timed against a visible clock, not a reaction to a stimulus, so no stop is judged too fast. A hidden tab during the free time means the person was not choosing on the page, so a percentile is withheld after one.
No percentile. Scores and quality flags only.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Points in the game | 10 points for each success (standard) | 10 points for each success (standard), No points |
| Blocks | One block, then free time (standard) | One block, then free time (standard), A block without points, then a block in the chosen condition, each followed by free time |
| Rounds per block | 20 | 10 to 40 |
| Free time (minutes) | 3 | 1 to 8 |
| Success window (ms either side of 5.00 s) | 50 | 20 to 150 |
| Payment line | Hypothetical points (standard) | Hypothetical points (standard), The study pays for points |
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 Reward and Interest Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Deci EL, 1971; Murayama K, Matsumoto M, Izuma K, Matsumoto K, 2010), with the standard settings (points in the game: 10 points for each success; blocks: One block, then free time; rounds per block: 20; free time (minutes): 3; success window (ms either side of 5.00 s): 50; payment line: Hypothetical points). The main score was free-time rounds (rounds of the game started in the free time after the last block, including one cut short when the free time ended).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Deci, E. L. (1971). Effects of externally mediated rewards on intrinsic motivation. Journal of Personality and Social Psychology, 18(1), 105–115. https://doi.org/10.1037/h0030644Free-choice period after rewarded puzzle solving, with a within-person baseline. Original game and items.
- Murayama, K., Matsumoto, M., Izuma, K., & Matsumoto, K. (2010). Neural basis of the undermining effect of monetary reward on intrinsic motivation. Proceedings of the National Academy of Sciences, 107(49), 20911–20916. https://doi.org/10.1073/pnas.1013305107A stopwatch game with performance-based reward or none, then voluntary play in a free-choice period.
- Deci, E. L., Koestner, R., & Ryan, R. M. (1999). A meta-analytic review of experiments examining the effects of extrinsic rewards on intrinsic motivation. Psychological Bulletin, 125(6), 627–668. https://doi.org/10.1037/0033-2909.125.6.627Free-choice behavior and self-reported interest as the two outcome measures.
Source papers
- Deci (1971); Murayama et al. (2010); Deci, Koestner and Ryan (1999): free-choice comparisons between rewarded and unrewarded groups.Paradigm source, Adults
Questions
How long does the Reward and Interest Task take?
About 7 to 9 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?
Free-Time Rounds, Free-Time Playing, Free-Time Reading, Played in Free Time, First Free-Time Round, Baseline Free-Time Rounds, Change in Free-Time Rounds, Interest Rating, Enjoyment Rating, Success Rate, Mean Stop Error, Points Won, Scored Rounds, Watch Ran Out, Stops Under 100 ms and Check Correct. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Reward and Interest Task used in research?
45 papers from 2021 to 2025 name it in their title or abstract, down 26% compared with 2016 to 2020. That ranks it 376 of 582 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.39.0, counted 8 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Reward and Interest Task have?
In the published research, 2 papers report its test-retest reliability and 0 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?
Points in the game (10 points for each success (standard), No points), blocks (One block, then free time (standard), A block without points, then a block in the chosen condition, each followed by free time), rounds per block (10 to 40), free time (minutes) (1 to 8), success window (ms either side of 5.00 s) (20 to 150) and payment line (Hypothetical points (standard), The study pays for points). 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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