jsPsych/docs/plugins/jspsych-instructions.md

jspsych-instructions plugin

This plugin is for showing instructions to the subject. It allows subjects to navigate through multiple pages of instructions at their own pace, recording how long the subject spends on each page. Navigation can be done using the mouse or keyboard. Subjects can be allowed to navigate forwards and backwards through pages, if desired.

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
pages	array	undefined	Each element of the array is the content for a single page. Each page should be an HTML-formatted string.
key_forward	string	'ArrowRight'	This is the key that the subject can press in order to advance to the next page. This key should be specified as a string (e.g., 'a', 'ArrowLeft', ' ', 'Enter').
key_backward	string	'ArrowLeft'	This is the key that the subject can press to return to the previous page. This key should be specified as a string (e.g., 'a', 'ArrowLeft', ' ', 'Enter').
allow_backward	boolean	true	If true, the subject can return to previous pages of the instructions. If false, they may only advace to the next page.
allow_keys	boolean	true	If true, the subject can use keyboard keys to navigate the pages. If false, they may not.
show_clickable_nav	boolean	false	If true, then a Previous and Next button will be displayed beneath the instructions. Subjects can click the buttons to navigate.
button_label_previous	string	'Previous'	The text that appears on the button to go backwards.
button_label_next	string	'Next'	The text that appears on the button to go forwards.
show_page_number	boolean	false	If true, and clickable navigation is enabled, then Page x/y will be shown between the nav buttons.
page_label	string	'Page'	The text that appears before x/y pages displayed when show_page_number is true.

Data Generated

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

Name	Type	Value
view_history	JSON string	A JSON string containing the order of pages the subject viewed (including when the subject returned to previous pages) and the time spent viewing each page.
rt	numeric	The response time in milliseconds for the subject to view all of the pages.

Example

Showing simple text instructions

var trial = {
	type: 'instructions',
	pages: [
		'Welcome to the experiment. Click next to begin.',
		'This is the second page of instructions.',
		'This is the final page.'
	],
	show_clickable_nav: true
}

Including images

var trial = {
	type: 'instructions',
	pages: [
		'Welcome to the experiment. Click next to begin.',
		'Here is a picture of what you will do: <img src="instruction_image.jpg"></img>'
	],
	show_clickable_nav: true
}