Decision Making
Effort Discounting Task
Also called: cognitive effort discounting, COG-ED, effort-based decision task
Measure how much mental effort lowers the value of a reward, with n-back levels named by color, adjusting choices against the 1-back and a subjective value for each level.
7-9 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
- 373
- Evidence grade
- B
- Registered clinical studies
- 46
What it measures
Measures how much mental effort lowers the value of a reward. Participants learn the n-back at 1, 2 and 3 back, each level named by a color, then choose between redoing the 1-back for fewer points and redoing a harder level for 640 points. Adjusting choices give the subjective value of each harder level.
Constructs
- Cognitive effort cost
- Motivation
- Working memory
Research uses
- Motivation and apathy research
- Aging research
- Within-study group comparison
How the paradigm works
The effort discounting task measures how much mental effort lowers the value of a reward. Participants first do the n-back at 1, 2 and 3 back. Letters appear one at a time every 2 seconds (a 500 ms cross, then the letter for 1,500 ms), and participants press the spacebar when a letter matches the one N letters back. Each level is named by a color drawn at random for the session. It starts with 10 practice letters with feedback after each one, then a block of 30 letters with 10 matches, followed by the share of matches caught. A study can run levels up to 2 or 4 back and 1 to 3 blocks per level.
More about the paradigm
Participants then make six choices for each harder level, in a random interleaved order: redo the 1-back for an adjusting number of points, or redo the harder level for 640 points. The 1-back offer starts at 320 points and moves by half the previous step after each choice, up after a harder choice and down after an easier one (160, 80, 40, 20, 10 and 5 points). The offer after the sixth step is the indifference point. The 1-back offer is on each side of the screen equally often. By default one choice is then picked at random and played out as one more block of the chosen task, so every choice counts. The points are not money.
The main score is the mean subjective value of the harder levels. A level's subjective value is its indifference point divided by 640: 1 means the harder level was worth as much as the 1-back, and values near 0 mean the participant gave up almost all the points to avoid it. The subjective value of each level, the area under the subjective value curve, the share of harder choices, n-back accuracy, d' and response time at each level, and choice time are also given. The procedure follows Westbrook, Kester and Braver (2013), who found that subjective value fell as the level rose, that older adults discounted effort more than younger adults, and that the area under the curve predicted Need for Cognition scores. The scores support research and do not diagnose.
Scores
- Mean Subjective Value%
- Mean subjective value of the harder levels: each level's indifference point divided by the 640 points offered for it.
- Higher means less discounting of effort
- Area Under the Curve%
- Area under the subjective value curve across the harder levels, by trapezoids. With the standard 2 and 3 back it equals the mean subjective value.
- Higher means less discounting of effort
- Subjective Value, 2-Back%
- Indifference point for the 2-back divided by 640.
- 1 means the 2-back was worth as much as the 1-back
- Subjective Value, 3-Back%
- Indifference point for the 3-back divided by 640.
- 1 means the 3-back was worth as much as the 1-back
- Subjective Value, 4-Back%
- Indifference point for the 4-back divided by 640, when the study runs it.
- 1 means the 4-back was worth as much as the 1-back
- Harder Choices%
- Share of choices for the harder level.
- Higher means more choices of effort
- N-Back Accuracy%
- Share of letters answered correctly in the blocks before the choices, all levels together.
- Higher is better
- Match Response Timems
- Mean time to press for a match in the blocks before the choices.
- Lower is faster
- Choice Timems
- Mean time to make a choice.
- Shows how long choices took
- Early Pressescount
- Presses under 100 ms after a letter appeared, counted as no press.
- Lower is better
- Play-Out Accuracy%
- Share of letters answered correctly in the block played out after the choices.
- Higher is better
Use and evidence
373 papers from 2021 to 2025 name this task in their title or abstract, up 79% compared with 2016 to 2020. That ranks it 67 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 112 |
| 2024 | 88 |
| 2023 | 64 |
| 2022 | 59 |
| 2021 | 50 |
| 2020 | 57 |
| 2019 | 51 |
| 2018 | 49 |
| 2017 | 27 |
| 2016 | 24 |
| 2015 | 24 |
| 2014 | 28 |
| 2013 | 19 |
| 2012 | 14 |
| 2011 | 13 |
| 2010 | 9 |
| 2009 | 10 |
| 2008 | 2 |
| 2007 | 1 |
| 2006 | 5 |
| 2005 | 4 |
| 2004 | 1 |
| 2003 | 0 |
| 2002 | 2 |
| 2001 | 0 |
| 2000 | 0 |
Use grade B
300 to 999 papers from 2021 to 2025.
Evidence grade B
At least 8 test-retest papers, and either 5 registered clinical studies or 150 reliability or validity papers.
- Papers on test-retest reliability
- 14
- Papers on reliability or validity
- 54
- Registered clinical studies using it as an outcome
- 46
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.
- Letters
- One every 2 seconds: a 500 ms cross, then the letter for 1,500 ms. Press the spacebar for a match.
- Levels
- 1 to 3 back (standard), or up to 2 or 4 back, each named by a color drawn from the session's seed.
- Practice
- 10 letters with feedback after each one, before each level.
- Blocks
- 1 block per level (standard, 1 to 3) of 30 letters with 10 matches, then the share of matches caught.
- Choices
- 6 per harder level, interleaved: redo the 1-back for an adjusting offer, or the harder level for 640 points.
- Offers
- The 1-back offer starts at 320 points and moves by 160, 80, 40, 20, 10 and 5 points, up after a harder choice and down after an easier one.
- Play-out
- One choice picked at random and done once more as a block of the chosen task (standard; can be turned off).
Westbrook and colleagues paid participants, asked for a response to every letter and gave three longer runs per level. This version uses the library's n-back, with a press only for matches, one block of 30 letters per level and points that are not money.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: effort_discounting_choice from the scored run, one per choice. Choices have no correct answer, so accuracy is not judged against chance. Choosing the same screen side on at least 90% of 12 or more choices invalidates, as do answers under 200 ms on at least half the choices. A familiarization block with no spacebar press is flagged for review.
Why these rules
There is no correct option to compare with chance, so accuracy is not judged against chance. The 1-back offer is on the left in half the choices and on the right in the others, so choosing by side alone means the offers were not read. A subjective value prices the effort of a level the participant has just done; a block of letters with no press at all suggests that level was not attempted. 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. A hidden tab lets a block of letters run without the participant, so a percentile is withheld after one.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Highest n-back level | 3 | 2 to 4 |
| Blocks per level | 1 | 1 to 3 |
| Play out one choice | On | On or off |
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 Effort Discounting Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Westbrook, Kester & Braver, 2013), with the standard settings (highest n-back level: 3; blocks per level: 1; play out one choice: On). The main score was mean subjective value (mean subjective value of the harder levels: each level's indifference point divided by the 640 points offered for it).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Westbrook, A., Kester, D., & Braver, T. S. (2013). What is the subjective cost of cognitive effort? Load, trait, and aging effects revealed by economic preference. PLoS ONE, 8(7), e68210. https://doi.org/10.1371/journal.pone.0068210
Source papers
- Westbrook A, Kester D, Braver TS (2013). What is the subjective cost of cognitive effort? Load, trait, and aging effects revealed by economic preference. PLoS ONE, 8(7):e68210.Paradigm source, Adults
Questions
How long does the Effort Discounting Task take?
About 7 to 9 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?
Mean Subjective Value, Area Under the Curve, Subjective Value, 2-Back, Subjective Value, 3-Back, Subjective Value, 4-Back, Harder Choices, N-Back Accuracy, Match Response Time, Choice Time, Early Presses and Play-Out Accuracy. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Effort Discounting Task used in research?
373 papers from 2021 to 2025 name it in their title or abstract, up 79% compared with 2016 to 2020. That ranks it 67 of 395 test families in the ConductCognition test census (use grade B). Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Effort Discounting Task have?
In the published research, 14 papers report its test-retest reliability and 46 registered clinical studies use it as an outcome (evidence grade B in the ConductCognition test census).
Which settings can a researcher change?
Highest n-back level (2 to 4), blocks per level (1 to 3) and play out one choice (On or off). 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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