One segment of text is shown at a time, with a blank which has to be filled in by one of the options provided.
clozelib/src/tasks/cloze.dart{
"segments": [
{
"text": "This is an .",
"blankPosition": 11,
"options": ["example", "text", "pineapple"],
"correctOptionIndex": 0
},
{
"text": "Segment without blanks."
},
...
]
}
NOTE: There can be at most one blank per segment. Only the first double brackets in the segment will replaced by the blank. correctOptionIndex is optional. If it is provided, the participant will get immediate feedback about the correctness after confirming their answer.
A random sequence of digits is presented one digit at a time, and the participant is asked to type the sequence from memory. If the sequence was typed correctly, the next sequence will be one digit longer. The task ends after some number of errors has been made.
digit-spanlib/src/tasks/digit_span.dart{
"excludeDigits": [0, 7],
"initialLength": 3,
"maxErrors": 2,
"secondsShowingDigit": 1.0,
"secondsBetweenDigits": 2.0,
"randomSeed": 42
}
NOTE: excludeDigits, initialLength, and maxErrors are optional. By default, all digits from 0 to 9 are included, the initial sequence length is 3, and the task ends after 2 failed trials. secondsShowingDigit and secondsBetweenDigits are optional and default to 0.5 and 1.5, respectively. randomSeed is an optional numerical seed for the random generation of digit sequences.
One word is shown at a time. The task is to determine whether it is a real word or a non-word. Similar to the original experiment described by Meyer and Schvaneveldt (1971), but showing single words instead of word pairs (though the task implementation allows newlines in words to display pairs).
lexical-decisionlib/src/tasks/lexical_decision.dart{
"words": ["WORD", "WROD", ...],
"correctAnswers": [true, false, ...]
}
NOTE: correctAnswers is optional and must be the same length as words. If it is provided, the participant will get immediate feedback about the correctness of their answer.
A single textual stimulus (usually a letter) is shown for 500 milliseconds with 2500 milliseconds between stimuli (these durations can be configured to different values). The participant taps the screen whenever they see the same stimulus as n stimuli back (a “positive” stimulus). Immediate positive or negative feedback is shown after each tap. The sequence of stimuli is randomly generated before each task.
n-backlib/src/tasks/n_back.dart{
"n": 2,
"stimulusChoices": ["A", "B", "C", ...],
"nStimuli": 20,
"nPositives": 5,
"secondsShowingStimulus": 1.0,
"secondsBetweenStimuli": 2.0,
"randomSeed": 42
}
NOTE: secondsShowingStimulus and secondsBetweenStimuli are optional and default to 0.5 and 1.5, respectively. randomSeed is an optional numerical seed for the random generation of stimulus sequences.
A textual stimulus is shown above a number of pictures. One of the pictures (or optionally a question mark, meaning “don’t know”) has to be selected.
picture-naminglib/src/tasks/picture_naming.dart{
"showQuestionMark": true,
"subtasks": [
{
"text": "Horse",
"pictures": [
"base64-encoded image",
"base64-encoded image",
"base64-encoded image"
],
"correctPictureIndex": 0
},
...
]
}
NOTE: The image should be adequately resized and compressed before encoding, especially for large numbers of subtasks, to keep HTTP response sizes low. correctPictureIndex is optional. If it is provided, the participant will get immediate feedback about the correctness after confirming their answer.
A single picture of a red balloon is shown at a time, which disappears with a popping animation as soon as it is being touched. A new one then appears in a (uniformly distributed) random location after a configurable amount of time.
reaction-timelib/src/tasks/reaction_time.dart{
"nStimuli": 20,
"minSecondsBetweenStimuli": 0,
"maxSecondsBetweenStimuli": 1.5,
"randomSeed": 42
}
NOTE: nStimuli does not include an introductory stimuli, which is already shown when starting the task. If minSecondsBetweenStimuli is smaller than maxSecondsBetweenStimuli, a (uniformly distributed) random number between them is generated after each stimulus. randomSeed is an optional numerical seed for the random generation of stimulus positions.
A text is presented (optionally with a preceding introductory text for context), followed by a series of ratings, followed by a number of single-answer multiple-choice questions to be answered. The questions are shown on the same screen as the text. The text is scrollable, and scrolling events are logged such that the visible range of text at each point in time can be reconstructed.
NOTE: On smaller screen sizes, the entire text box (including the font size) is scaled down in order to preserve the number of characters per line across devices.
readinglib/src/tasks/reading.dart{
"intro": "This is to provide some *context*.",
"text": "This is an example text.",
"textWidth": 300,
"textHeight": 200,
"fontSize": 25.0,
"lineHeight": 2.0,
"ratings": [
{
"question": "How easy was it?",
"type": "emoticon",
"lowExtreme": "very difficult",
"highExtreme": "very easy"
},
...
],
"questions": [
{
"question": "Question?",
"answers": [
"Answer 1",
"Answer 2",
],
"correctAnswerIndex": 0
},
...
],
}
NOTE: text can be Markdown. intro is an optional Markdown text to be shown before the actual text. fontSize is optional and specifies the font size of the text (not the questions; default is 20.0). lineHeight is optional and specifies the line spacing factor (default is 1.5). questions is optional. If it is not provided, the questions stage is skipped. ratings is optional. If it is not provided, the ratings stage is skipped. Ratings follow the same format as the ratings at the end of the task (described in the API specs). correctAnswerIndex is optional. If it is provided, the participant will receive feedback and are required to correct their answers.
Four buttons are shown. They light up in a specific sequence, which has to be repeated by pressing the buttons in the same order. After each successful repetition, a random item is added to the sequence, and the sequence is shown again. Inspired by the electronic game Simon.
simon-gamelib/src/tasks/simon_game.dartCircular buttons with numbers or letters are presented, which have to be connected in the correct order by tapping on them. In a variation of the task, the buttons have different colors and have to be connected in a trail of alternating colors (e.g. black 1 → white 2 → black 3 → …), avoiding distractors (cf. Kim et al., 2014).
trail-makinglib/src/tasks/trail_making.dart{
"stimuli": ["1", "2", "3", "4", "5", "6"],
"colors": ["FFFFFF", "000000"],
"nDistractors": 4,
"gridWidth": 5,
"gridHeight": 7,
"jiggle": true,
"randomSeed": 42
}
NOTE: colors is optional and specifies the alternating colors of the buttons. nDistractors is only allowed when there are at least 2 colors and specifies the number of distractor buttons (same stimuli, but wrong color). gridWidth, gridHeight, jiggle are optional and determine the spatial distribution of the buttons. randomSeed is an optional numerical seed for the random generation of stimulus positions and distractors.