Episodic Memory
Category Lists Task
Also called: semantic interference task, proactive semantic interference, retroactive semantic interference, category-cued recall
Measure interference between word lists: participants study two lists from the same categories and type the words they remember, with recovery after another study.
8-10 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
- 49
- Evidence grade
- C
- Registered clinical studies
- 2
What it measures
Measures recall, interference between lists and recovery with another study. Participants study two word lists from the same categories, then type the words from each.
Constructs
- Semantic interference
- Category-cued recall
- Verbal learning
- Retrieval
Research uses
- Memory and learning research
- Aging research
- Studies of proactive and retroactive interference
How the paradigm works
The Category Lists Task measures how learning a related list changes recall. Participants study two original lists drawn from the same three categories, with category names shown during study and recall. Each list is studied and recalled twice; the first list is then recalled again. This sequence separates initial interference, improvement after restudy and recall of the earlier list after the competing one.
More about the paradigm
The task uses 12 words per list, typed category recall and original items in eight languages. The published semantic-interference procedure informs the sequence, while these materials and administration are our own. Proactive cost compares A2 with B1; recovery compares B2 with B1; retroactive cost compares A2 with A3. A contrast is reported only when both stages are complete. Intrusions retain the distinction between the competing list, another category and words outside the test lists.
Scores
- Proactive Cost%
- A2 recall proportion minus B1 recall proportion.
- Positive means lower recall on the first study of B
- List A1 Recall%
- Share of list words recalled under their own category at A1.
- Higher means more words recalled
- List A2 Recall%
- Share of list words recalled under their own category at A2.
- Higher means more words recalled
- List B1 Recall%
- Share of list words recalled under their own category at B1.
- Higher means more words recalled
- List B2 Recall%
- Share of list words recalled under their own category at B2.
- Higher means more words recalled
- List A3 Recall%
- Share of list words recalled under their own category at A3.
- Higher means more words recalled
- Recovery%
- B2 minus B1 recall proportion.
- Positive means recall rose after restudy
- Residual Cost%
- A2 minus B2 recall proportion.
- Positive means lower recall of B after restudy
- Retroactive Cost%
- A2 minus A3 recall proportion.
- Positive means lower recall of A after B
- Cross-List Intrusionscount
- Words from the competing list typed during recall.
- Context for interference
- List A1 Intrusionscount
- Competing-list words typed at A1.
- Context for interference
- List A2 Intrusionscount
- Competing-list words typed at A2.
- Context for interference
- List B1 Intrusionscount
- Competing-list words typed at B1.
- Context for interference
- List B2 Intrusionscount
- Competing-list words typed at B2.
- Context for interference
- List A3 Intrusionscount
- Competing-list words typed at A3.
- Context for interference
- Wrong-Category Wordscount
- Target-list words typed under another category.
- Context for recall
- Other Intrusionscount
- Entries naming neither test list, including practice words.
- Context for recall
- Repeatscount
- Repeated matched words within a category recall.
- Context for recall
- Words Recalledcount
- Correct target words across the five recalls.
- Higher means more words recalled
- Entries Typedcount
- Scored entries across category recalls.
- Context for recall
- Paste Attemptscount
- Blocked attempts to paste into recall.
- Should be 0
- Recalls Completedcount
- Distinct category recalls completed.
- 15 in a full run
- Recalls Plannedcount
- Category recalls planned for the run.
- 15
Use and evidence
49 papers from 2021 to 2025 name this task in their title or abstract, up 40% compared with 2016 to 2020. That ranks it 366 of 582 test families in our census. See the counts for every test.
Show the numbers
| Year | Papers |
|---|---|
| 2025 | 12 |
| 2024 | 11 |
| 2023 | 10 |
| 2022 | 9 |
| 2021 | 7 |
| 2020 | 5 |
| 2019 | 5 |
| 2018 | 8 |
| 2017 | 9 |
| 2016 | 8 |
| 2015 | 4 |
| 2014 | 0 |
| 2013 | 3 |
| 2012 | 0 |
| 2011 | 0 |
| 2010 | 1 |
| 2009 | 0 |
| 2008 | 0 |
| 2007 | 1 |
| 2006 | 2 |
| 2005 | 0 |
| 2004 | 1 |
| 2003 | 1 |
| 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
- 5
- Papers on reliability or validity
- 22
- Registered clinical studies using it as an outcome
- 2
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.
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 10 November 2026 from OpenAlex and ClinicalTrials.gov.
Task design
The trial sequence as the test runs in ConductCognition.
- Lists
- 2 lists of 12 words, each with 4 words from each of 3 categories: birds, tools and vegetables. Original items in all eight app languages.
- Sequence
- Study and recall A1, restudy and recall A2, study and recall B1, restudy and recall B2, then recall A3 without restudy. Each stage recalls the three categories separately, 15 category recalls in all.
- Study
- Each word appears with its category for 3,000 ms (standard; 1,000 to 5,000), then a 250 ms blank. The session seed assigns words to lists and orders study words and recall categories.
- Recall
- Up to 20 seconds per category (standard; 10 to 60), with a visible timer and Done button. Type one word at a time. Case, accents, leading articles and listed plural or spelling forms are accepted; other spelling errors are not corrected. Japanese kana and kanji and Chinese simplified and traditional forms are listed explicitly.
- Scores
- Proactive cost is A2 minus B1 recall proportion. Recovery is B2 minus B1, residual cost A2 minus B2, and retroactive cost A2 minus A3. Recall in each stage and cross-list, wrong-category and other intrusions are reported separately.
- Practice
- 3 dessert words followed by untimed recall and the number recalled. Practice does not enter the scores.
These contrasts measure recall across this sequence. There is no unrelated-list control. The words are original, and typed category recall differs from the published spoken procedure. Some common words appear in other library tasks; use a separate session when studying interference.
Quality checks
Each session is marked valid, needs review or invalid, with the reason, before you see its scores.
Scored rows: category_lists_recall from the run with most recall rows, practice excluded. Recall has no chance level. No recall, incomplete runs and blocked paste attempts are flagged. A hidden tab withholds the percentile.
Why these rules
Recall of two category lists measures learning and interference; a low score can be a real result. Incomplete stages cannot support contrasts. 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 |
|---|---|---|
| Time per word (ms) | 3,000 | 1,000 to 5,000 |
| Recall time per category (seconds) | 20 | 10 to 60 |
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 Category Lists Task in a web browser (ConductCognition task version 1.0.0, scoring version 1.0.0; Crocco et al., 2014), with the standard settings (time per word (ms): 3,000; recall time per category (seconds): 20). The main score was proactive cost (A2 recall proportion minus B1 recall proportion).
ConductCognition versions: task version 1.0.0, scoring version 1.0.0. Every export records the versions each session used, for a methods section.
- Crocco, E., Curiel, R. E., Acevedo, A., Czaja, S. J., & Loewenstein, D. A. (2014). An Evaluation of Deficits in Semantic Cueing and Proactive and Retroactive Interference as Early Features of Alzheimer's Disease. The American Journal of Geriatric Psychiatry, 22(9), 889-897. https://doi.org/10.1016/j.jagp.2013.01.066Repeated learning of two semantically related lists and return to the first list; our words and typed category recall are an adaptation.
Source papers
- Crocco, E., Curiel, R. E., Acevedo, A., Czaja, S. J., & Loewenstein, D. A. (2014). An Evaluation of Deficits in Semantic Cueing and Proactive and Retroactive Interference as Early Features of Alzheimer's Disease. The American Journal of Geriatric Psychiatry, 22(9), 889-897.Paradigm source
Questions
How long does the Category Lists Task take?
About 8 to 10 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?
Proactive Cost, List A1 Recall, List A2 Recall, List B1 Recall, List B2 Recall, List A3 Recall, Recovery, Residual Cost, Retroactive Cost, Cross-List Intrusions, List A1 Intrusions, List A2 Intrusions, List B1 Intrusions, List B2 Intrusions, List A3 Intrusions, Wrong-Category Words, Other Intrusions, Repeats, Words Recalled, Entries Typed, Paste Attempts, Recalls Completed and Recalls Planned. Each session is also marked valid, needs review or invalid, with the reason.
How widely is the Category Lists Task used in research?
49 papers from 2021 to 2025 name it in their title or abstract, up 40% compared with 2016 to 2020. That ranks it 366 of 582 test families in the ConductCognition test census (use grade D). Source: ConductCognition test census 0.39.0, counted 10 November 2026 from OpenAlex and ClinicalTrials.gov.
How much reliability evidence does the Category Lists Task have?
In the published research, 5 papers report its test-retest reliability and 2 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?
Time per word (ms) (1,000 to 5,000) and recall time per category (seconds) (10 to 60). 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, with its words in the same language. 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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