Experiments | Paradigm Class

The experimental task isolated by an experimental contrast is called the paradigm class. Typically, these paradigms are well-known and used by many different researchers with only minor changes. Some experiments may have more than one paradigm class.

After each paradigm class name is a series of links with more information. The Ⓕ shows an example dataset from our functional data­base. The ➊ is to the original or oldest found reference. A ✪ is for the most cited reference in the database.


Paradigm Class Definition
Stimulation with filamentous needles to elicit cognitive, behavioral, and/or physiological responses.
Affective Pictures
Stimuli utilize affective images to elicit a range of emotions.
Affective Words
Stimuli utilize words that are concerned with or arouse feelings or emotions.
Make a saccade (directed rapid eye movement) away from target.
Braille Reading
Read Braille words with their finger(s).
Chewing /
Chew edible or non-edible items, and may be asked to swallow the food/nonfood item.
Classical Conditioning
Respond to a previously neutral stimulus that has been repeatedly paired with an unconditioned (positive/negative) stimulus that elicits the desired response.
Competition /
Work together with another participant to achieve a common goal, or strive to gain/win something by defeating another participant.
Counting /
Count, add, subtract, multiply, or divide various stimuli (numbers, bars, dots, etc.) or solve numerical word problems.
Cued Explicit
A list of items (words, objects, textures, patterns, pictures, sounds) is presented and participants are subsequently tested with cues to recall previously presented material.
Perform a task and either lie or be truthful in his/her response.
Delay Discounting
Perform a reward task, and is asked to choose between a small immediate reward or large delayed reward.
Match to Sample
A stimulus that is followed by a probe item after a brief delay; subject is then asked to recall if the probe item was presented before the delay.
Divided Auditory
Respond to an auditory stimuli (tone or word) while performing an unrelated task. If the participants are presented with tones, then this is also often co-coded with Tone Monitor/Discrimination.
Draw lines, circles or more complex figures using a pen or stylus.
Control the operation and movement of a vehicle in a real or simulated driving environment.
Emotion Induction
Stimuli with emotional valence (e.g., statements, films, music, pictures) to induce effect on mood.
Emotional Body
Language Perception
The recognition of emotions expressed by another’s body pose, posture or body movement. Tasks usually require participants to infer the emotional meaning of non-verbal stimuli by paying particular attention to head, hand and body cues in the judgment of emotionally valent criteria. Based on popular beliefs that certain body postures communicate things like deceit/lying, pain/discomfort and sexual interest and cognitive neuroscience models that the purport that the visual system analyzes human motion differently from object motion.
Memorize stimuli such as words, pictures, letters, etc. Includes Incidental Encoding, which is a task in which the participant is creating new memories without purposely knowing that memorization is the task at hand. Participants’ memories are created through working in their environment and picking up information in the process.
Episodic Recall
Recall from episodic memory (autobiographical, long-term memories) in a guided/unguided manner. Episodic information can be personal experiences as well as the specific objects, people, and events experienced at a particular time and place and can involve, for example, items defined as constituting discrete story elements or personal memories such as those elicited from each participant during a pre-scanning interview and then recalled via recording/script in the scanner.
Task does NOT probe semantic memory (memory of facts or concepts) in which participants are asked to recall stimuli that was memorized prior to scanning - those are coded as Cued Explicit Recognition/Recall. Recall of traumatic events are coded as Trauma Recall, not Episodic Recall. Recall of memories to elicit emotions such as happiness or sadness, should be co-coded with Emotion Induction.
Calculate approximately the amount, extent, magnitude, position, or value of something.
Face Monitor /
View face passively or discriminate human faces according to their order, gender, location, emotion, or appearance, etc. If the participants view the faces passively, then the experiment is co-coded with Passive Viewing.
Figurative Language
Respond to items/statements that convey non-literal/figurative language. Figurative language includes: similes, metaphors, personification, alliteration, onomatopoeia, hyperbole, idioms, proverbs, irony, sarcasm, metonymy, and clichés.
Film Viewing
View movies or film clips.
Finger Tapping /
Button Press
Tap fingers or press a button in a cued/non-cued manner. Used for all experiments with a response type of Finger.
Direct attention or gaze toward a visual stimulus, often a cross.
Respond to target stimulus that is surrounded by distracting or facilitating stimuli.
Flashing Checkerboard
Flashing or reverse high contrast checkerboard.
Flexion /
Move (flex and extend) hands, arms, legs, feet, lips, tongue, etc.
Fluency Induction
Perform different fluency tasks in order to enhance the smoothness or flow with which sounds, syllables, words and phrases are joined together when speaking quickly. Tasks often including: verbal (semantic and/or phonological), perceptual (frequency, duration, font size, ease/difficulty to understand, and/or attractiveness), or speech production (masking, chorus reading, whispering, rhythmic stimulation, metronome pacing).
Free List
Word Recall
Study a list of words presented in different order on successive trials; and then prompted to recall the items in any order.
Make decisions about chance gambles.
Perform a binary decision (go or no-go) on a continuous stream of stimuli.
Grasp or grip a presented stimulus with their hand or mimic grasping one that is not physically present (i.e., imaginary or presented as a picture or video).
Hand-Eye Coordination
Coordinate eye movement with hand movement to process visual input and guide a behavioral response (i.e., spatial/orientation discrimination, motor planning, timing, monitoring, response selection, motor [sequence] learning).
Hunger / Satiety
The desire to eat, or to satisfy one's appetite. Measures often include pre-post hunger and satiety state, and/or hedonic value (reward/punishment) of food or solution.
Hypercapnia /
Air Hunger
The state of excessive carbon dioxide in the bloodstream, typically caused by inadequate respiration. Classically known as respiratory distress or air-hunger, it can be experimentally induced by having the subject perform a static apnea or breath-holding task; by training subjects to use a mechanical ventilator or using an experimenter-controlled air-supply device; or by having the subject inhale different mixtures of oxygen and carbon dioxide.
Imagined Movement
Subjects imagine performing some motor task (e.g., walking, reaching).
Imagined Objects /
Visualize patterns, objects, scenes, places, concepts, real/hypothetical events (not from personal memories), in a cued/non-cued manner.
Induced Panic
Experimentally induced panic created by injection or inhalation of chemicals, usually done to create trigger symptoms in individuals that resemble those of panic attacks or anticipatory anxiety.
Isometric Force
Use hands or fingers to apply isometric force or complete a precision grip task.
Lexical Decision
Discriminate between words and pseudowords (orthographically and phonologically legal nonwords).
Magnitude Comparison (Distance)
Perform a task in which the distance between stimuli is estimated.
Magnitude Comparison (Luminance)
Perform a task in which the luminance or intensity of light between stimuli is estimated.
Magnitude Comparison (Physical Size)
Perform a task in which the physical size between stimuli is estimated.
Magnitude Comparison (Symbolic/Numerical)
Perform a task in which the differences between symbols or numbers is estimated (e.g., choose the larger Arabic numeral or number).
Magnitude Comparison (Non-symbolic/Numerical)
Perform a task in which the differences between non-symbols or numbers is estimated (e.g., choose the more numerous array of dots).
Conscious mental process that induces a relaxation response. Concominant measures often include cognitive, behavior, and or physiological activity.
Mental Rotation
Mentally rotate visually presented 2D and 3D figures.
Think about voiding urine, or provide urine samples.
Motor Learning
Repeatedly execute a motor task to improve performance.
Perform simultaneous execution of one or more tasks that can be presented in different modalities
Music Comprehension
Listen to tones, melodies, chords, dissonant/consonant music, rhythms, spoken lyrics, musical excerpts/notes.
Music Production
Produce music by singing (overly/covertly), or by playing an instrument.
Indicate when the current stimulus matches the one from n steps earlier in the sequence. Load factor n can be adjusted to make the task more or less difficult.
Naming (Covert)
View objects (pictures, line drawings, etc.) and name them silently.
Naming (Overt)
View objects (pictures, line drawings, etc.) and name them aloud.
Object Manipulation
/ Discrimination
Physically interact with one or more objects, and/or discriminate between its physical (shape, color, texture) and/or semantic properties (use, previous experience, relationship to other objects).
Oddball Discrimination
Detect the presence of an oddball (infrequent/distinct) stimulus from a continuous stream of stimuli. Examples include when participants listen to tones and indicate when they hear a target tone (oddball) or when participants view letters or objects and indicate when they see a target stimulus (oddball).
Olfactory Monitor /
Smell odors passively and/or discriminate according to some feature (pleasant/unpleasant, strong/weak, same/different, etc.).
Orthographic Discrimination
View letters and discriminate according to some written/printed feature (i.e., upper­case­/­lower­case, alphabetic order, same­/­different spelling of words, vowel­/­consonant, font type­/­size).
Pain Monitor /
Stimulation (i.e., thermal, electrical, tactile) at a painful threshold.
Paired Associate
Encode paired items, and subsequently asked to recall the associated pair.
Passive Listening
Listen to auditory stimuli (speech, noise, tones, etc.) and make no response. If the participants are presented with tones, then this is also often co-coded with Tone Monitor/Discrimination. If the participants are presented with music, i.e., a melody not just tones, then code as Music Comprehension.
Passive Viewing
View visual stimuli (objects, faces, letter strings, etc.) and make no response. If the presented stimuli are faces, the experiments are co-coded with Face Monitor/Discrimination. If presented stimuli are words, the experiments are not coded as passive viewing but rather as Reading (Covert).
Phonological Discrimination
View or listen to phonemes, syllables, or words and discriminate according to some feature of their sounds (rhyming, number of syllables, homophones, pronounceable nonwords, etc.).
Pitch Monitor /
Listen passively or discriminate stimuli (human speech and non-speech vocalizations, animal vocalization, mechanical noise, etc.) based on pitch (i.e., duration, familiarity, pleasantness, gender, frequency). If participants only listen passively, then also co-code with Passive Listening.
Point at a target mentally or physically (e.g., point with finger, or imagine pointing with finger).
Pursuit Rotor /
Manual Tracking
Follow/pursue a small disc on a rotating turntable. Co-coded with Motor Learning if participants are given practice trials to improve performance and accuracy.
Reading (Covert)
Silently read words, pseudo-words, characters, phrases, or sentences.
Reading (Overt)
Read aloud words, pseudo-words, logograms, phrases, or sentences.
Reasoning /
Problem Solving
Make judgements, inferences, generalizations and/or conclusions through the use of logic. Tasks can include integration of different elements/information, probabilistic class­ification, text comprehension, falsification of a conditional rule, and word problems.
Recitation /
Repetition (Covert)
Silently repeat or recite phonemes, words, or well-known text (nursery rhymes, Pledge of Allegiance, months of the year, etc.).
Recitation /
Repetition (Overt)
Repeat or recite aloud phonemes, words, or well-known text (nursery rhymes, Pledge of Allegiance, months of the year, etc.).
Rest passively with eyes open or closed. Often used as a baseline for comparison for other tasks.
A stimulus that serves the role of reinforcing a desired response. Participants perform a task in which correct performance is associated with reward, often monetary reward.
Perform a rapid eye movement or saccade to capture an object in the visual field.
Meditate or think about one's character, actions, and motives. Co-code with the paradigm "Meditation" if this is part of a meditation task.
Semantic Monitor /
Discriminate between the meanings of individual lexical items or to indicate if target word is semantically related to the probe word. Stimuli in discrimination tasks can be words or pictures representing words.
Sequence Recall /
Learn and/or perform a complex sequence of finger tapping, button pressing, pointing/clicking, or various other motor responses.
Sexual Arousal /
Induction of sexual readiness with or without sexual climax.
Sleep with or without sleep stage monitoring.
Name the color of the ink for a list of words (color names) printed in congruent/incongruent colors, or determine if ink color and color name are congruent/incongruent. Color-congruent stimuli: ink color and color name are the same (e.g., the word "GREEN" printed in green ink). Color-incongruent stimuli: ink color and color name differ (e.g., the word "GREEN" printed in red ink).
Report the number of words presented regardless of the word meaning. Congruent stimuli: semantic meaning and numerical value match (e.g., word "TWO" presented twice on the screen). Incongruent stimuli: semantic meaning and numerical value differ (e.g., word "TWO" presented four times). Neutral stimuli: semantic meaning and numerical value are unrelated (e.g., word "DOG" presented four times).
Name the ink color of emotionally charged words (i.e., positively or negatively valenced words).
The spatial Stroop effect demonstrates interference between the stimulus location with the location information in the stimuli. It is elicited when the direction of the arrow is incompatible with its spatial location. For example, subjects are presented with a word either to the right or left of a central fixation point. For congruent trials, subjects see either the word ‘right’ presented to the right of fixation, or the word ‘left’ presented to the left of fixation. For incongruent trials, subjects see either the word ‘right’ presented to the left of fixation or the word ‘left’ presented to the right of fixation.
Allocate attentional resources to process a specific stimulus feature in a context with competing (interfering), typically more prepotent, information.
Syntactic Discrimination
Discriminate between grammatically correct and incorrect sentences. This class also includes morphosyntactic tasks such as gender discrimination of words.
Tactile Monitor /
Manipulate, recognize and/or discriminate objects through touch (i.e., shape, texture, same-different).
Task Switching
Switch from one task or goal to another.
Discriminate/rate flavor intensity, pleasantness, solution content (i.e., fat content) of an item, food, or solution with or without swallowing the item. Participants may be asked to evaluate the affective significance of other stimuli (i.e., pictures, words, objects) when paired with food.
Theory of Mind
Understand another's personal beliefs and feelings or form hypotheses regarding the mental states of others.
Thirst Induction
Inducing a sensation of dryness in the mouth and throat associated with a desire for liquids; dehydration.
Tone Monitor /
Listen to tones passively or discriminate according to a sound property (e.g., order, timing, pitch, frequency, amplitude), and/or detect presence/absence of a tone.
Tower of London
Mentally or physically rearrange a set of three (or more) colored beads/discs arranged on pegs, in the fewest possible moves, to match a specified configuration. Also includes Tower of Hanoi tests for taxonomic parsimony.
Transcranial Magnetic
Electromagnetic pulses are applied at the scalp to induce electrical currents in the brain (TMS).
Trauma Recall
Cued recall/re-experience of a previous traumatic event. Often achieved using a patient-generated script or set of cues calling to mind the trauma.
Vestibular Stimulation
Vestibular (labyrinthine) excitability under caloric, mechanic, or turning stimulation. Galvanic Vestibular Stimulation: uses direct current electricity stimulation to stimulate vestibular system. Also includes Caloric Vestibular Stimulation, a task in which cold and warm water to stimulate the vestibular system.
Vibrotactile Monitor/
Vibrotactile stimulation (perception of vibration through touch) to skin or joints.
Video Games
Play video games often to measure emotional changes (e.g., aggression), perceptual learning/transfer of skills, or skilled vs. unskilled players.
Visual Motion
Infer the speed and direction of elements in a scene based on visual input, or discriminate between coherent/incoherent biological motion.
Visual Object
Identify an object based on its visual attributes (e.g., shape, color, viewing angle), or detect/discriminate changes on the object's visual properties (e.g., size, illumination, position, relation between parts).
Visual Pursuit /
Observe a moving target(s) and track its movement across the screen, or track visual changes on the moving target (e.g., velocity, trajectory, location in space).
Visuospatial Attention
Make cued/noncued shifts of visual attention to a particular spatial location in the visual field. Responses can be overt (with eye movement to target location) or covert (fixating on a central target while paying attention to spatial location changes of peripheral target). Also includes the Posner and Simon task.
Card Sorting Test
Sort cards into groups based on some dimension (i.e., color, form, or number) that is changed intermittently, and requires participants to identify a new correct group dimension.
Word Generation
Semantic: Listen to or view nouns and silently generate an associated verb, or view a category and silently generate as many exemplars as possible.
Orthographic: Listen to or view a letter and silently generate as many words as possible that start with that letter.
Phonologic: Listen to or view a word and silently generate words that rhyme.
Word Generation
Semantic: Listen to or view nouns and overtly generate an associated verb, or view a category and overtly generate as many exemplars as possible. Orthographic: Listen to or view a letter and overtly generate as many words as possible that start with that letter. Phonologic: Listen to or view a word and overtly generate words that rhyme.
Word Imageability
Participants are presented with a task that reflects how easy or difficult it is to imagine a word.
Word Stem
Completion (Covert)
Silently generate a word that completes the word stem.
Word Stem
Completion (Overt)
Overtly generate a word that completes the word stem.
Write letters or words with a pen, stylus, or their finger.

The oldest found reference is the same as the most cited reference.

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