jsPsych/docs/plugins/jspsych-reconstruction.md

jspsych-reconstruction plugin

This plugin allows a subject to interact with a stimulus by modifying a parameter of the stimulus and observing the change in the stimulus in real-time.

The stimulus must be defined through a function that returns an HTML-formatted string. The function should take a single value, which is the parameter that can be modified by the subject. The value can only range from 0 to 1. See the example at the bottom of the page for a sample function.

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
stim_function	function	undefined	A function with a single parameter that returns an HTML-formatted string representing the stimulus.
starting_value	numeric	0.5	The starting value of the stimulus parameter.
step_size	numeric	0.05	The change in the stimulus parameter caused by pressing one of the modification keys.
key_increase	string	'h'	The key to press for increasing the parameter value.
key_decrease	string	'g'	The key to press for decreasing the parameter value.
button_label	string	'Continue'	The text that appears on the button to finish the trial.

Data Generated

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

Name	Type	Value
start_value	numeric	The starting value of the stimulus parameter.
final_value	numeric	The final value of the stimulus parameter.
rt	numeric	The length of time, in milliseconds, that the trial lasted.

Examples

???+ example "Make a block larger and smaller" === "Code" ```javascript var sample_function = function(param){ var size = 50 + Math.floor(param*250); var html = '

'+ '

Press "h" to make the square larger. Press "g" to make the square smaller.

'+ '

When the square is the same size as the previous one, click Continue.

'; return html; }

    var match_item = {
        type: 'html-keyboard-response',
        stimulus: '<div style="display: block; margin: auto; height: 300px; width: 300px; position: relative;">'+
        '<div style="display: block; position: absolute; top: '+(150 - 210/2)+'px; left:'+(150 - 210/2)+'px; background-color: #000000; '+
        'width: 210px; height: 210px;"></div></div>',
        choices: ['c'],
        post_trial_gap: 1250,
        prompt: '<p>Study the size of this square carefully. On the next screen you will have to recreate it. When you are ready, press "c".</p>'
    }

    var reconstruction = {
        type: 'reconstruction',
        stim_function: sample_function,
        starting_value: 0.5,
    }
    ```
=== "Demo"
    <div style="text-align:center;">
        <iframe src="/demos/jspsych-reconstruction-demo1.html" width="90%;" height="500px;" frameBorder="0"></iframe>
    </div>

<a target="_blank" rel="noopener noreferrer" href="/demos/jspsych-reconstruction-demo1.html">Open demo in new tab</a>