jspsych-image-slider-response

This plugin displays an image.The stimulus can be displayed until a response is given, or for a pre-determined amount of time. The trial can be ended automatically if the subject has failed to respond within a fixed length of time.

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
stimulus string undefined The path to the image file to be displayed.
labels array of strings [] Labels displayed at equidistant locations on the slider. For example, two labels will be placed at the ends of the slider. Three labels would place two at the ends and one in the middle. Four will place two at the ends, and the other two will be at 33% and 67% of the slider width.
button_label string 'Continue' Label of the button to advance/submit
min integer 0 Sets the minimum value of the slider
max integer 100 Sets the maximum value of the slider
start integer 50 Sets the starting value of the slider
step integer 1 Sets the step of the slider
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 key to press).
stimulus_duration numeric null How long to show the stimulus for in milliseconds. If the value is null, then the stimulus will be shown until the subject makes a response.
trial_duration numeric null How long to wait for the subject to make a response before ending the trial in milliseconds. If the subject fails to make a response before this timer is reached, the subject's response will be recorded as null for the trial and the trial will end. If the value of this parameter is null, then the trial will wait for a response indefinitely.
response_ends_trial boolean true If true, then the trial will end whenever the subject makes a response (assuming they make their response before the cutoff specified by the timing_response parameter). If false, then the trial will continue until the value for trial_duration is reached. You can use this parameter to force the subject to view a stimulus for a fixed amount of time, even if they respond before the time is complete.

Data Generated

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

Name Type Value
response numeric The numeric value of the slider.
rt numeric The time in milliseconds for the subject to make a response. The time is measured from when the stimulus first appears on the screen until the subject's response.
stimulus string The path of the image that was displayed.

Examples

Displaying trial until subject gives a response

var trial = {
    type: 'image-slider-response',
    stimulus: 'img/happy_face_1.png',
    labels: ['happy', 'sad'],
    prompt: "<p>How happy/sad is this person?</p>",
  response_ends_trial: false
};