# jspsych-free-sort plugin The free-sort plugin displays a collection of images on the screen that the subject can interact with by clicking and dragging. All of the moves that the subject performs are recorded. ## Dependency This plugin requires the jQuery UI library, available at [https://jqueryui.com/](https://jqueryui.com/). You must include the library in the `` section of your experiment page. You can use the [Google-hosted version of the library](https://developers.google.com/speed/libraries/#jquery-ui). ## 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 ----------|------|---------------|------------ stimuli | array | *undefined* | Each element of this array is an image path. stim_height | numeric | 100 | The height of the images in pixels. stim_width | numeric | 100 | The width of the images in pixels. sort_area_height | numeric | 800 | The height of the container that subjects can move the stimuli in. Stimuli will be constrained to this area. sort_area_width | numeric | 800 | The width of the container that subjects can move the stimuli in. Stimuli will be constrained to this area. prompt | string | null | This string can contain HTML markup. 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). prompt_location | string | "above" | Indicates whether to show the prompt `"above"` or `"below"` the sorting area. button_label | string | 'Continue' | The text that appears on the button to continue to the next trial. ## 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 -----|------|------ init_locations | JSON string | A JSON-encoded object representing the initial locations of all the stimuli in the sorting area. The object is an array with one element per stimulus. Each element in the array has a "src", "x", and "y" value. "src" is the image path, and "x" and "y" are the object location. moves | JSON string | A JSON-encoded object representing all of the moves the participant made when sorting. The object is an array with each element representing a move. Each element in the array has a "src", "x", and "y" value. "src" is the image path, and "x" and "y" are the object location after the move. final_locations | JSON string | A JSON-encoded object representing the final locations of all the stimuli in the sorting area. The object is an array with one element per stimulus. Each element in the array has a "src", "x", and "y" value. "src" is the image path, and "x" and "y" are the object location. rt | numeric | The response time in milliseconds for the subject to finish all sorting. ## Examples #### Basic example ```javascript var sorting_stimuli = []; for (var i = 1; i <= 12; i++) { sorting_stimuli.push("img/cell_img_" + i + ".jpg"); } var sort_trial = { type: 'free-sort', stimuli: sorting_stimuli, prompt: "

Click and drag the images below to sort them so that similar items are close together.

" }; ```