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Task Library

The Metricis assessment platform ships with 36 instruments spanning cognitive performance tests and patient-reported outcomes (PROs). Studies select a subset (a battery) rather than running everything — see Cognitive Assessments for how batteries are configured, run, and synced.

All performance tasks are touch-first and run in a mobile browser or the native Metricis app (iOS / Android). PROs use standard rating-scale UIs (Likert, eVAS, single best answer). Task source lives in client/src/tasks/; central parameter overrides live in client/src/config.ts (TASK_CONFIG).

At a glance

Domain Count Tasks
Attention 7 ANT, Choice RT, CPT (Go/No-Go), Divided Attention, Flanker, MOT, Vigilance CPT
Working memory 5 Corsi Block-Tapping, Digit Span, Letter–Number Switching, N-Back, Operation Span
Processing speed 2 Digit-Symbol Coding, Simple Reaction Time
Executive function 6 Matrix Reasoning, Probabilistic Reversal Learning, Stroop, Tower Task, Trail Making (A/B), WCST
Episodic memory 5 Pattern Separation, Picture Sequence Memory, Source Memory, Verbal Paired Associates, Visual Paired Associates
Language 3 Semantic Fluency, Sentence Comprehension, Vocabulary
Social cognition 2 Emotion Recognition, Theory of Mind
Decision-making 1 Delay Discounting
Patient-reported outcomes 5 Brain Fog Scale, COMPASS-31, FACS, MFIS, PROMIS Pediatric Profile-25

Attention

Attention Network Test (ANT) — attention-network-test

Posner-style task that isolates three attention networks — alerting, orienting, and executive control — using cue conditions and a flanker conflict manipulation. Outputs network-specific RT contrasts plus overall accuracy.

Choice Reaction Time — choice-rt

Pop-out visual search: three colored squares appear and the participant taps the one that doesn't match the other two. Indexes perceptual processing speed and visual attention.

CPT / Go–No-Go — cpt-go-nogo

Sustained attention and response inhibition. Participants tap for frequent GO targets (stars) and withhold for infrequent NO-GO stimuli (moons). Outputs omission errors, commission errors, d-prime, mean RT, and RT variability.

Divided Attention — divided-attention

Dual-stream task in which the participant monitors two concurrent visual (or visual + auditory) channels and responds to targets in each. Outputs single-task vs. dual-task cost.

Flanker — flanker

Eriksen flanker. Participant identifies the direction of a center arrow flanked by congruent or incongruent arrows. Outputs the congruency effect (incongruent − congruent RT) and accuracy.

Multiple Object Tracking (MOT) — mot

Participant tracks a subset of moving objects among visually identical distractors. Difficulty scales with the number of tracked targets; outputs tracking accuracy and an estimated attentional capacity.

Vigilance CPT — vigilance-cpt

Long-duration CPT (~400 trials over 4 blocks) designed specifically to capture the vigilance decrement — how detection of rare targets degrades over sustained effort. Complements the shorter CPT/Go-No-Go.

Working memory

Corsi Block-Tapping — corsi-blocks

Visuospatial span. The participant watches blocks light up in sequence and reproduces the pattern by tapping. Sequence length increases adaptively; outputs forward span.

Digit Span — digit-span

Auditory/visual digit sequences recalled forward (short-term memory) and backward (working memory manipulation). Outputs forward and backward span and longest sequence correct.

Letter–Number Switching — letter-number-switching

Task-switching paradigm. The participant alternates between sorting by letter and by number depending on a cue. Outputs switch cost (switch − repeat RT) and error rates.

N-Back — n-back

Working memory updating. Participant indicates when the current stimulus matches the one shown N trials earlier (1-back for younger / lower ability, 2-back otherwise). Outputs hits, false alarms, d-prime, and RT.

Operation Span — operation-span

Complex span task: the participant solves brief math problems while remembering a sequence of letters between problems. Outputs partial-credit unit score (working memory capacity under interference).

Processing speed

Digit-Symbol Coding — digit-symbol

Participant uses an on-screen symbol–digit key to identify the digit paired with each symbol as fast as possible. Indexes psychomotor and information processing speed.

Simple Reaction Time — simple-rt

Tap as soon as a single target (a star) appears. Strips out decision and selection demands to isolate basic motor/perceptual latency. Used as a baseline for slowing in fatigue/illness contexts.

Executive function

Matrix Reasoning — matrix-reasoning

Visual analogy / pattern completion items modeled on Raven's-style matrices. Selects the option that completes the rule in a 3×3 grid. Indexes fluid reasoning.

Probabilistic Reversal Learning — probabilistic-reversal

Two-choice learning task with probabilistic feedback and reversed contingencies mid-task. Outputs learning rate, perseverative errors after reversal, and adaptation latency.

Stroop — stroop

Color–word interference. Participant reports the ink color of color words. Outputs the Stroop effect (incongruent − neutral/congruent RT) and accuracy.

Tower Task — tower-task

Tower of Hanoi / London variant. Participant moves discs from start to goal configuration in the fewest legal moves. Outputs moves-to-solution, planning latency, and rule violations.

Trail Making (A & B) — trail-making

Part A: connect numbers in order (speed). Part B: alternate between numbers and shapes (set-shifting). Outputs Part A time, Part B time, and the B − A difference as an executive control cost.

Wisconsin Card Sorting Test (WCST) — wcst

Card sorting by an unstated rule (color / shape / number) that changes silently after each set. Outputs categories completed, perseverative errors, non-perseverative errors, and trials to first category.

Episodic memory

Pattern Separation — pattern-separation

Mnemonic Similarity Task (MST)-style paradigm. Participant studies objects then later distinguishes targets from highly similar lures. Outputs the Lure Discrimination Index — a sensitive marker of hippocampal pattern separation.

Picture Sequence Memory — picture-sequence-memory

Based on the NIH Toolbox PSMT. Participant views a sequence of pictures with narration and reconstructs the order. Indexes episodic memory for temporal order.

Source Memory — source-memory

Distinguishes item memory ("Did I see this?") from source memory ("Where / how did I see it?"). Outputs source accuracy controlling for item recognition — a hippocampal-binding marker.

Verbal Paired Associates — verbal-paired-associates

Learn word–word pairs at study; at test, see a cue word and select its associate. Outputs paired-associate learning score and reaction time.

Visual Paired Associates — visual-paired-associates

Learn object–location associations; at test, place each object in its remembered location. Outputs spatial binding accuracy and displacement error.

Language

Semantic Fluency — semantic-fluency

Generate as many exemplars of a category as possible in a fixed time (e.g., animals, foods). Outputs total correct, cluster size, and switching. Sensitive to executive search strategy and semantic store integrity.

Sentence Comprehension — sentence-comprehension

Picture- or sentence-judgment task contrasting simple vs. syntactically complex structures (e.g., object-relative clauses, passives). Outputs accuracy and RT separately for simple and complex syntax.

Vocabulary — vocabulary

Multiple-choice synonym task with age-graded difficulty. Indexes crystallized verbal knowledge.

Social cognition

Emotion Recognition — emotion-recognition

Identify the emotion (happy / sad / angry / fearful / neutral) shown by an animated face. Outputs per-emotion accuracy and overall sensitivity.

Theory of Mind — theory-of-mind

False-belief and mental-state inference vignettes. Participant predicts another person's behavior given their (mistaken) beliefs or perspective. Indexes mentalizing.

Decision-making

Delay Discounting — delay-discounting

Forced choice between a smaller-sooner and larger-later reward, with delays and amounts varied to estimate the discount rate (k). Indexes impulsivity / time preference.

Patient-Reported Outcomes (PROs)

Brain Fog Scale (BFS) — brain-fog-scale

30-item self-report covering cognitive symptoms (17 items), physiological symptoms (8), and psychological symptoms (5). Total score plus subscale scores.

COMPASS-31 — compass31

31-item validated autonomic symptom inventory across six domains (orthostatic, vasomotor, secretomotor, gastrointestinal, bladder, pupillomotor) with weighted scoring producing a 0–100 total score.

Fatigue and Cognitive Symptoms Scale (FACS) — facs

20-item PRO measuring fatigue and cognitive symptom burden via electronic Visual Analog Scales (eVAS) on each item. Captures both intensity and impact on daily functioning.

Modified Fatigue Impact Scale (MFIS) — mfis

21-item scale measuring the impact of fatigue on physical (9), cognitive (10), and psychosocial (2) functioning. Standard MS / chronic illness measure.

PROMIS Pediatric Profile-25 (v2.0) — promis

NIH PROMIS short-form bundle covering six domains — physical function/mobility, anxiety, depressive symptoms, fatigue, peer relationships, pain interference — plus a single pain intensity rating. Outputs T-scores per domain.

How a study uses this

  • A study defines its battery as an ordered list of these tasks (sometimes with task-specific parameter overrides, e.g., 1-back vs. 2-back, number of trials). Battery construction is documented in Cognitive Assessments.
  • Tasks can run individually (single-session) or chained with built-in breaks and progress UI.
  • All tasks emit a standardized summary (per-task scalar metrics) plus raw trial-level data for offline analysis.
  • Bilingual support (English / French) is enabled for all instruction text; task stimuli vary by modality.