# jspsych-audio-slider-response

This plugin plays audio files and records responses generated with a button click.

If the browser supports it, audio files are played using the WebAudio API.This allows for reasonably precise timing
of the playback. The timing of responses generated is measured against the WebAudio specific clock, improving the measurement
of response times. If the browser does not support the WebAudio API, then the audio file is played with HTML5 audio. Audio
files are automatically preloaded by jsPsych.

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

This table lists the parameters associated with this plugin. 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 | audio file | *undefined* | Audio file to be played
labels | array of keycodes/strings | Labels of the slider
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
step | integer | 1 | Sets the step of the slider
prompt | String | '' | 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 | integer | -1 | How long to show the stimulus for in milliseconds. If the value is -1, then the stimulus will be shown until the subject makes a response.
trial duration | numeric | -1 | 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 the subject's response will be recorded as -1 for the trial and the trial will end. If the value of this parameter is -1, 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](overview#datacollectedbyplugins), 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.

## Examples

#### Displaying trial until subject gives a response

```javascript
var trial = {
	type: 'audio-slider-response',
	stimulus: 'sound/tone.mp3',
	labels: ['low', 'high'],
	prompt: "<p>Is the pitch high or low?</p>",
  response_ends_trial: false
};
```