jspsych-serial-reaction-time plugin¶

The serial reaction time plugin implements a generalized version of the SRT task (Nissen & Bullemer, 1987). Squares are displayed in a grid-based system on the screen, and one square changes color. The participant presses a key that corresponds to the darkened key. Feedback is optionally displayed, showing the participant which square the key they pressed matches.

Parameters¶

In addition to the parameters available in all plugins, this plugin accepts the following parameters. Parameters with a default value of undefined must be specified. Other parameters can be left unspecified if the default value is acceptable.

Parameter	Type	Default Value	Description
target	array	undefined	The location of the target. The array should be the `[row, column]` of the target.
grid	array	`[[1,1,1,1]]`	This array represents the grid of boxes shown on the screen. Each inner array represents a single row. The entries in the inner arrays represent the columns. If an entry is `1` then a square will be drawn at that location on the grid. If an entry is `0` then the corresponding location on the grid will be empty. Thus, by mixing `1`s and `0`s it is possible to create many different grid-based arrangements.
choices	array of strings	`[['3','5','7','9']]`	The dimensions of this array must match the dimensions of `grid`. Each entry in this array is the key that should be pressed for that corresponding location in the grid. Entries can be left blank if there is no key associated with that location of the grid.
grid_square_size	numeric	100	The width and height in pixels of each square in the grid.
target_color	hex color code	`#999`	The color of the target square.
response_ends_trial	boolean	`true`	If true, the trial ends after a key press. Feedback is displayed if `show_response_feedback` is true.
pre_target_duration	numeric	0	The number of milliseconds to display the grid before the target changes color.
trial_duration	numeric	null	The maximum length of time of the trial, not including feedback.
show_response_feedback	boolean	false	If true, show feedback indicating where the user responded and whether it was correct.
feedback_duration	numeric	200	The length of time in milliseconds to show the feedback.
fade_duration	numeric	null	If a positive number, the target will progressively change color at the start of the trial, with the transition lasting this many milliseconds.
prompt	string	null	This string can contain HTML markup. Any content here will be displayed below the stimulus. The intention is that it can be used to provide a reminder about the action the subject is supposed to take (e.g., which keys to press).

Data Generated¶

In addition to the default data collected by all plugins, this plugin collects the following data for each trial.

Name	Type	Value
grid	array	The representation of the grid. This will be encoded as a JSON string when data is saved using the `.json()` or `.csv()` functions.
target	array	The representation of the target location on the grid. This will be encoded as a JSON string when data is saved using the `.json()` or `.csv()` functions.
response	string	Indicates which key the subject pressed.
rt	numeric	The response time in milliseconds for the subject to make a response. The time is measured from when the second stimulus first appears on the screen until the subject's response.
correct	boolean	`true` if the subject's response matched the target.

Examples¶

A classic SRT

Code

var instructions = {
  type: 'html-button-response',
  stimulus: '<p>Use the S, F, H, and K keys to respond.</p>',
  choices: ['Continue']
}

var grid = [
  [1,1,1,1]
]

var response_map = [
  ['s','f','h','k']
]

var trial_1 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [0,0]
}
var trial_2 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [0,1]
}
var trial_3 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [0,2]
}
var trial_4 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [0,3]
}

Demo

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2x2 grid with feedback

Code

var instructions = {
  type: 'html-button-response',
  stimulus: '<p>Use the R, I, V, and M keys to respond.</p>',
  choices: ['Continue']
}

var grid = [
  [1,1],
  [1,1]
]

var response_map = [
  ['r','i'],
  ['v','m']
]

var trial_1 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [0,0],
  show_response_feedback: true,
  feedback_duration: 500
}
var trial_2 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [0,1],
  show_response_feedback: true,
  feedback_duration: 500
}
var trial_3 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [1,1],
  show_response_feedback: true,
  feedback_duration: 500
}
var trial_4 = {
  type: 'serial-reaction-time',
  grid: grid,
  choices: response_map,
  target: [1,0],
  show_response_feedback: true,
  feedback_duration: 500
}

Demo

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