Episodic Memory
Remember and Know Test
Also called: remember/know paradigm, remember-know task, R/K procedure, remember-know-guess paradigm, recollection and familiarity task
Separate recollection from familiarity: participants say which pictures they saw and whether they remember seeing each one, just know it, or guess.
8-11 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
- 115
- Evidence grade
- C
- Registered clinical studies
- 10
What it measures
Separates recollection from familiarity in recognition memory. After a list of pictures, each test picture is answered Seen or New, and each Seen answer is marked Remember, Know or Guess.
Constructs
- Recollection
- Familiarity
- Recognition memory
- Episodic memory
Research uses
- Research on recollection and familiarity in aging, amnesia and mild cognitive impairment
- Studies of memory in schizophrenia, depression and other conditions
- Experimental research on encoding and recognition
How the paradigm works
The Remember and Know Test separates two ways of recognizing something seen before: remembering the moment it was seen (recollection) and simply knowing it was there (familiarity). Participants study a list of pictures of everyday objects, animals and simple scenes, each shown for 2 seconds after a cross. After the list, each test picture is answered Seen or New with no time limit. After Seen, the participant says whether they remember seeing it in the list, know it was there without remembering seeing it, or are guessing.
More about the paradigm
The task follows the remember/know procedure of Tulving (1985) and Gardiner (1988), with the guess option of Gardiner, Ramponi and Richardson-Klavehn (1998). The instructions say that a know answer can be as sure as a remember answer, so that remember is not read as high confidence (Migo, Mayes and Montaldi 2012). True-or-false arithmetic fills a 60-second delay between the list and the test, adjustable from 0 to 120 seconds. The standard list has 24 pictures, and the test shows them with 24 new ones; a setting gives 16 to 24. A practice of 3 pictures comes first, with a short test of those 3 and 1 new picture and feedback on Seen or New.
The pictures are 52 Noto Emoji pictures, chosen by a stated rule: none that another test in the library shows. Each session gives every picture its role at random: studied or new.
The main score is the recollection estimate: the share of studied pictures given a remember answer minus the share of new pictures given one (Yonelinas and Jacoby 1995). The familiarity estimate follows the independence remember/know method: know answers over the pictures not given a remember answer, for studied minus new pictures, also reported as d′. Hit and false alarm rates, d′, corrected recognition, the remember, know and guess rates and answer times are also reported. With 24 studied pictures, each estimate rests on few answers, so group comparisons are safer than single scores. Scores support research and do not diagnose.
Scores
- Recollection Estimate%
- Share of studied pictures answered Remember minus share of new pictures answered Remember.
- Higher means more recollection
- Familiarity Estimate%
- Know answers over pictures not answered Remember, for studied pictures minus new pictures (independence remember/know).
- Higher means more familiarity for studied pictures
- Familiarity d-Primed'
- z of the familiarity rate for studied pictures minus z for new pictures, with the log-linear correction.
- Higher means more familiarity for studied pictures
- Hit Rate%
- Share of studied pictures answered Seen.
- Higher is better
- False Alarm Rate%
- Share of new pictures answered Seen.
- Lower is better
- d-Primed'
- z(hit rate) minus z(false alarm rate), with the log-linear correction.
- Higher means better recognition
- Corrected Recognition%
- Hit rate minus false alarm rate.
- Higher is better
- Remember Rate, Studied%
- Share of studied pictures answered Remember.
- Higher means more recollection
- Remember Rate, New%
- Share of new pictures answered Remember.
- Lower is better
- Know Rate, Studied%
- Share of studied pictures answered Know.
- Context for the familiarity estimate
- Know Rate, New%
- Share of new pictures answered Know.
- Lower is better
- Guess Rate, Studied%
- Share of studied pictures answered Guess.
- Informational
- Guess Rate, New%
- Share of new pictures answered Guess.
- Informational
- Remember Share of Hits%
- Remember answers among studied pictures answered Seen.
- Informational
- Answer Time, Hitsms
- Median time to answer Seen to studied pictures.
- Context for the hit rate
- Answer Time, Correct Rejectionsms
- Median time to answer New to new pictures.
- Context for the false alarm rate
- Judgment Timems
- Median time to choose Remember, Know or Guess.
- Informational
- Anticipationscount
- Seen or New answers faster than 100 ms, left out of every score.
- Lower is better
- Pictures Testedcount
- Test pictures shown in the scored run (48 at the standard settings).
- Informational
- Delay Arithmetic Accuracy%
- Share of true-or-false arithmetic problems in the delay answered correctly.
- Context for the delay
- Delayseconds
- Seconds of arithmetic between the study list and the test.
- Informational
Use and evidence
115 papers from 2021 to 2025 name this task in their title or abstract, down 20% compared with 2016 to 2020. That ranks it 175 of 395 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 26 |
| 2024 | 15 |
| 2023 | 21 |
| 2022 | 30 |
| 2021 | 23 |
| 2020 | 24 |
| 2019 | 26 |
| 2018 | 20 |
| 2017 | 29 |
| 2016 | 44 |
| 2015 | 39 |
| 2014 | 35 |
| 2013 | 46 |
| 2012 | 33 |
| 2011 | 58 |
| 2010 | 54 |
| 2009 | 44 |
| 2008 | 62 |
| 2007 | 64 |
| 2006 | 43 |
| 2005 | 30 |
| 2004 | 37 |
| 2003 | 34 |
| 2002 | 21 |
| 2001 | 12 |
| 2000 | 17 |
Use grade C
100 to 299 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
- 1
- Papers on reliability or validity
- 21
- Registered clinical studies using it as an outcome
- 10
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 of objects, animals and simple scenes from Noto Emoji, none shown by another test: 48 for the test and 4 for practice.
- Study list
- 24 pictures (standard; 16 to 24), each after a 500 ms cross for 2,000 ms.
- Delay
- 60 seconds of true-or-false arithmetic (standard; 0 to 120).
- Test
- Every studied picture and as many new ones, 48 in all, answered Seen or New with no time limit. After Seen, the participant chooses Remember, Know or Guess. No more than 4 old or new pictures in a row.
- Practice
- 3 pictures, then a test of those 3 and 1 new picture with 1,500 ms of feedback on Seen or New.
- Roles
- Each session gives every picture its role at random: studied or new.
Most remember/know studies use words. Pictures are recognized well, so remember answers tend to be common; the familiarity estimate rests on the pictures not remembered.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: remember_know_test from the scored run, one Seen or New answer per picture, each Seen answer with Remember, Know or Guess, and the delay arithmetic from the same run. Seen or New accuracy significantly below chance (one-sided exact binomial, p < .05, chance 50%) invalidates; accuracy not above chance over 10 or more answers is flagged. The same answer on 90% of the pictures invalidates when accuracy is not above chance. Answers under 200 ms on at least half of 4 or more answered pictures invalidate. No arithmetic answered in the delay, or delay arithmetic at or below chance over at least 10 answers, is flagged. A hidden tab withholds the percentile.
Why these rules
Half the test pictures were studied and half are new, so guessing gives 50%: 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). 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. Remember, know and guess describe the participant's own experience and have no right answer, so they are never judged. Skipping the delay arithmetic means that part of the procedure may not have been followed. A hidden tab lets the study, delay or response timers run without the participant, so a percentile is withheld after one.
Running this test
Settings you can change
| Setting | Standard | Allowed |
|---|---|---|
| Pictures studied | 24 | 16 to 24 |
| Arithmetic delay (seconds) | 60 | 0 to 120 |
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.
- Recruiting online? See the setup guides for Prolific, Sona Systems, CloudResearch Connect and Qualtrics.
Cite and describe
Participants completed the Remember and Know Test in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Tulving, 1985; Gardiner, 1988), with the standard settings (pictures studied: 24; arithmetic delay (seconds): 60). The main score was recollection estimate (share of studied pictures answered Remember minus share of new pictures answered Remember).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Tulving, E. (1985). Memory and consciousness. Canadian Psychology, 26(1), 1-12. https://doi.org/10.1037/h0080017
- Gardiner, J. M. (1988). Functional aspects of recollective experience. Memory & Cognition, 16(4), 309-313. https://doi.org/10.3758/BF03197041
- Gardiner, J. M., Ramponi, C., & Richardson-Klavehn, A. (1998). Experiences of remembering, knowing, and guessing. Consciousness and Cognition, 7(1), 1-26. https://doi.org/10.1006/ccog.1997.0321The guess answer.
- Yonelinas, A. P., & Jacoby, L. L. (1995). The relation between remembering and knowing as bases for recognition: Effects of size congruency. Journal of Memory and Language, 34(5), 622-643. https://doi.org/10.1006/jmla.1995.1028The recollection and familiarity estimates.
- Migo, E. M., Mayes, A. R., & Montaldi, D. (2012). Measuring recollection and familiarity: Improving the remember/know procedure. Consciousness and Cognition, 21(3), 1435-1455. https://doi.org/10.1016/j.concog.2012.04.014Instructions that keep know answers apart from low confidence.
Source papers
- Tulving E (1985). Memory and consciousness. Canadian Psychology, 26(1):1-12.Paradigm source, Adults
- Gardiner JM (1988). Functional aspects of recollective experience. Memory & Cognition, 16(4):309-313.Paradigm source, Adults
- Gardiner JM, Ramponi C, Richardson-Klavehn A (1998). Experiences of remembering, knowing, and guessing. Consciousness and Cognition, 7(1):1-26.Paradigm source, Adults
- Yonelinas AP, Jacoby LL (1995). The relation between remembering and knowing as bases for recognition: effects of size congruency. Journal of Memory and Language, 34(5):622-643.Paradigm source, Adults
- Migo EM, Mayes AR, Montaldi D (2012). Measuring recollection and familiarity: improving the remember/know procedure. Consciousness and Cognition, 21(3):1435-1455.Paradigm source, Adults
Questions
How long does the Remember and Know Test take?
About 8 to 11 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?
Recollection Estimate, Familiarity Estimate, Familiarity d-Prime, Hit Rate, False Alarm Rate, d-Prime, Corrected Recognition, Remember Rate, Studied, Remember Rate, New, Know Rate, Studied, Know Rate, New, Guess Rate, Studied, Guess Rate, New, Remember Share of Hits, Answer Time, Hits, Answer Time, Correct Rejections, Judgment Time, Anticipations, Pictures Tested, Delay Arithmetic Accuracy and Delay. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Remember and Know Test used in research?
115 papers from 2021 to 2025 name it in their title or abstract, down 20% compared with 2016 to 2020. That ranks it 175 of 395 test families in the ConductCognition test census (use grade C). Source: ConductCognition test census 0.14.0, counted 31 October 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Remember and Know Test have?
In the published research, 1 paper reports its test-retest reliability and 10 registered clinical studies use it as an outcome (evidence grade C in the ConductCognition test census).
Which settings can a researcher change?
Pictures studied (16 to 24) and arithmetic delay (seconds) (0 to 120). 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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