DRM False Memory Task

Version: v1 (current)

The Deese-Roediger-McDermott paradigm for studying false memory creation and recognition.

Overview

The DRM (Deese-Roediger-McDermott) False Memory task demonstrates how memory is constructive rather than simply reproductive. Participants study lists of semantically related words (e.g., bed, rest, awake, tired) that all converge on a non-presented critical lure word (e.g., sleep). During recognition testing, participants frequently and confidently report having seen the lure word, despite it never being presented.

This robust false memory effect reveals fundamental properties of human memory: we encode the gist or meaning of experiences, not just verbatim details. The DRM paradigm has become a standard tool for investigating memory distortion, source monitoring, and the neural basis of true versus false memories.

The task is widely used in memory research, forensic psychology, aging studies, and clinical assessments of memory dysfunction.

Scientific Background

Classic Findings:

High False Recognition: Critical lures are falsely recognized at rates of 60-80%, often matching or exceeding true recognition rates
Confidence: Participants are highly confident in their false memories of lures
Immediate vs. Delayed: False recognition can increase over time as gist memory strengthens
Warning Effect: Explicit warnings about the lure reduce but do not eliminate false recognition
Individual Differences: False memory rates correlate with certain personality traits and frontal lobe function

Key Mechanisms:

Spreading Activation: Study words activate related concepts including the non-presented lure
Gist vs. Verbatim: Memory preserves semantic gist more reliably than exact details
Source Monitoring Errors: Failure to distinguish between externally presented and internally generated information

Seminal Papers:

Roediger, H.L., & McDermott, K.B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21(4), 803-814.
Schacter, D.L., Norman, K.A., & Koutstaal, W. (1998). The cognitive neuroscience of constructive memory. Annual Review of Psychology, 49, 289-318.

Why Researchers Use This Task

Memory Research: Study constructive nature of memory and gist-based encoding
Forensic Psychology: Understand eyewitness memory distortions and suggestibility
Aging Studies: Assess age-related changes in memory accuracy and false recognition
Clinical Assessment: Evaluate memory monitoring in schizophrenia, amnesia, and dementia
Individual Differences: Investigate personality, intelligence, and cognitive style correlates

Configuration Options

Timing Parameters

Parameter	Type	Default	Description
Study word duration	number	2000ms	Default duration each word appears during study phase (can be overridden per-list)
Inter-stimulus interval	number	500ms	Default pause between study words (can be overridden per-list)
Retention interval	number	0ms	Delay between study and test phases (0 = immediate test)
Test word duration	number	0ms	Response timeout for test items (0 = self-paced)

Per-List Timing: You can customize timing for individual study lists using the per-list columns in the study lists spreadsheet (see Trial Configuration below).

Visual Parameters

Parameter	Type	Default	Description
Font size	number	48px	Text size for word display (8-400px)

Trial Configuration

The task consists of two phases: Study Phase (encoding word lists) and Test Phase (recognition testing).

Study Lists

Each study list is defined with the following columns:

Column	Description	Example	Required
list_name	Thematic identifier for the list	"Sleep", "Sweet", "Thread"	✅ Yes
critical_lure	The unpresented word that participants may falsely recognize	"sleep", "sweet", "needle"	✅ Yes
study_words	Comma-separated words to present during study (typically 10-15 words)	"bed, rest, awake, tired, dream..."	✅ Yes
Study Duration (ms)	Per-list override for study word duration	2000, 1500, 2500	❌ Optional
ISI (ms)	Per-list override for inter-stimulus interval	500, 300, 700	❌ Optional

Example Study List:

| list_name | critical_lure | study_words | Study Duration (ms) | ISI (ms) |
|-----------|---------------|-------------|---------------------|----------|
| Sleep     | sleep         | bed, rest, awake, tired... | 2000 | 500 |
| Sweet     | sweet         | sour, candy, sugar... | 1500 | 300 |

Per-List Timing Customization: The optional timing columns allow you to vary presentation speed across lists. For example:

Use faster timing (1500ms duration, 300ms ISI) for easier lists
Use slower timing (2500ms duration, 700ms ISI) for more difficult lists or when testing older adults
Leave blank to use the general default timing parameters

If you set the same timing values for all lists, the task behaves as if you only set the general defaults.

Unrelated Lures

In addition to studied words and critical lures, the test phase should include unrelated lures, that is, words that are not semantically related to any study list. These serve as a baseline for false alarms.

Enter unrelated lures as a comma-separated list in the study form (e.g., "window, pencil, chair, lamp, book").

Test Phase Structure

The test phase automatically presents:

Studied words: A selection of words that were actually presented
Critical lures: The non-presented theme words from each list
Unrelated lures: Words unrelated to any list

Participants respond "Old" (word was in study list) or "New" (word was not in study list).

Instructions

The task supports custom instructions for each phase:

Instruction Type	When Shown	Purpose
Main instructions	Before the entire task	Explains the overall task structure
Study instructions	Before study phase begins	Tells participants to remember the words
Test instructions	Before test phase begins	Explains the old/new recognition procedure
Hint instructions	Available via "?" button	Quick reminder accessible during the task

Data Output

Markers and Responses

The task records high-resolution timestamps in two separate collections. Phase transitions are also marked (e.g., drm_study_phase_start, drm_test_phase_start, drm_retention_interval_start).

Markers (stimulus_shown - study phase):

{
  "type": "stimulus_shown",
  "ts": "2024-01-01T00:00:01.000Z",
  "hr": 1234.56,
  "data": {
    "trial_index": 1,
    "stimulus_id": "drm_0_study_1",
    "word": "bed",
    "list_name": "Sleep",
    "word_position": 1,
    "list_position": 1,
    "study_word_duration_ms": 2000,
    "isi_duration_ms": 500
  }
}

Markers (stimulus_shown - test phase):

{
  "type": "stimulus_shown",
  "ts": "2024-01-01T00:01:00.000Z",
  "hr": 60234.56,
  "data": {
    "trial_index": 1,
    "stimulus_id": "drm_0_test_1",
    "word": "sleep",
    "item_type": "critical_lure",
    "list_name": "Sleep",
    "test_word_duration_ms": 0
  }
}

Response Data (test phase):

{
  "trial_index": 1,
  "stimulus_id": "drm_0_test_1",
  "word": "sleep",
  "item_type": "critical_lure",
  "list_name": "Sleep",
  "response_value": "old",
  "response_correct": false,
  "source": "button",
  "latency_ms": 1450
}

Summary Artifact

A JSON file (drm_summary_<taskIndex>.json) with comprehensive false memory statistics:

{
  "task_kind": "drm_false_memory",
  "total_trials": 60,
  "overall": {
    "accuracy": 0.75,
    "mean_rt_ms": 1450
  },
  "by_item_type": {
    "studied": {
      "total": 30,
      "hits": 26,
      "hit_rate": 0.87
    },
    "critical_lure": {
      "total": 6,
      "false_alarms": 4,
      "false_alarm_rate": 0.67
    },
    "unrelated_lure": {
      "total": 24,
      "false_alarms": 3,
      "false_alarm_rate": 0.13
    }
  },
  "false_memory_effect": 0.54,
  "trials": [ /* per-trial data */ ]
}

Key metrics:

hit_rate: Proportion of studied words correctly recognized as "old"
critical_lure_false_alarm_rate: Proportion of critical lures falsely recognized as "old"
unrelated_lure_false_alarm_rate: Proportion of unrelated lures falsely recognized as "old"
false_memory_effect: Difference between critical and unrelated lure false alarm rates

Design Recommendations

Standard DRM Protocol

Study Phase:

6-10 word lists, 15 words per list
1500-2000ms per word
500ms inter-stimulus interval

Test Phase:

All critical lures (one per list)
5-8 studied words per list
Equal number of unrelated lures
Self-paced responses

Instructions: Standard "remember the words" (no warning about lures unless comparing warning conditions)

Population-Specific Adaptations

Older Adults (65+):

Slower study pace (2000-2500ms per word)
Larger font (60px or larger)
Fewer lists (4-6 instead of 6-10) to reduce fatigue
Longer inter-stimulus interval (750ms)

Children (10+ years):

Use concrete, age-appropriate word lists
Shorter lists (10 words per list)
Slower presentation (2000ms per word)
Simplified instructions with examples

Clinical Populations:

Adjust list length and number based on severity
Consider delayed testing intervals (retention_interval_ms)
May need recognition confidence ratings for detailed analysis

Advanced Configurations

Warning Study:

Same as standard, but include explicit warning in test instructions: "Some test words will be related to studied words but were NOT presented"
Compare false recognition rates with vs. without warning

Delayed Testing:

Use retention_interval_ms to add a delay (e.g., 30000ms = 30 seconds, or 600000ms = 10 minutes)
False memory often increases with delay as gist memory strengthens

Common Issues and Solutions

Issue	Solution
Low hit rate for studied words	Increase study duration per word (2000-2500ms) or reduce list length
Low false alarm rate for critical lures	Use high backward associative strength (BAS) lists; increase list length (15 words)
High false alarm rate for unrelated lures	Ensure lures are truly unrelated; verify participants understand old/new distinction
Participant awareness of lures	Avoid explicit warnings unless comparing warning conditions
Fatigue effects	Reduce number of lists (4-6); add retention interval as a break

Participant Experience

Main Instructions: Overview of the task (study and test phases)
Study Instructions: Told to remember the words
Study Phase: Words appear one at a time (e.g., bed → rest → awake → tired...)
Retention Interval (optional): Brief pause or distractor task
Test Instructions: Explanation of old/new recognition
Test Phase: For each word, respond "Old" (was studied) or "New" (was not studied)
Completion: Task finishes after all test items

Note: Participants are typically unaware of the critical lure manipulation and experience strong feelings of familiarity for these non-presented words.

References

Roediger, H.L., & McDermott, K.B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21(4), 803-814.
Schacter, D.L., Norman, K.A., & Koutstaal, W. (1998). The cognitive neuroscience of constructive memory. Annual Review of Psychology, 49, 289-318.
Stadler, M.A., Roediger, H.L., & McDermott, K.B. (1999). Norms for word lists that create false memories. Memory & Cognition, 27(3), 494-500.

Overview​

Scientific Background​

Why Researchers Use This Task​

Configuration Options​

Timing Parameters​

Visual Parameters​

Trial Configuration​

Study Lists​

Unrelated Lures​

Test Phase Structure​

Instructions​

Data Output​

Markers and Responses​

Summary Artifact​

Design Recommendations​

Standard DRM Protocol​

Population-Specific Adaptations​

Advanced Configurations​

Common Issues and Solutions​

Participant Experience​

References​

See Also​