animation

This plugin displays a sequence of images at a fixed frame rate. The sequence can be looped a specified number of times. The subject is free to respond at any point during the animation, and the time of the response is recorded.

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
stimuli	array	undefined	Each element of the array is a path to an image file.
frame_time	numeric	250	How long to display each image (in milliseconds).
frame_isi	numeric	0	If greater than 0, then a gap will be shown between each image in the sequence. This parameter specifies the length of the gap.
sequence_reps	numeric	1	How many times to show the entire sequence. There will be no gap (other than the gap specified by frame_isi) between repetitions.
choices	array of strings	"ALL_KEYS"	This array contains the key(s) that the subject is allowed to press in order to respond to the stimulus. Keys should be specified as characters (e.g., 'a', 'q', ' ', 'Enter', 'ArrowDown') - see this page and this page (event.key column) for more examples. Any key presses that are not listed in the array will be ignored. The default value of "ALL_KEYS" means that all keys will be accepted as valid responses. Specifying "NO_KEYS" will mean that no responses are allowed.
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(s) to press).
render_on_canvas	boolean	true	If true, the images will be drawn onto a canvas element. This prevents a blank screen (white flash) between consecutive images in some browsers, like Firefox and Edge. If false, the image will be shown via an img element, as in previous versions of jsPsych.

Data Generated

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

Name	Type	Value
animation_sequence	array	An array, where each element is an object that represents a stimulus in the animation sequence. Each object has a stimulus property, which is the image that was displayed, and a time property, which is the time in ms, measured from when the sequence began, that the stimulus was displayed. The array will be encoded in JSON format when data is saved using either the .json() or .csv() functions.
response	array	An array, where each element is an object representing a response given by the subject. Each object has a stimulus property, indicating which image was displayed when the key was pressed, an rt property, indicating the time of the key press relative to the start of the animation, and a key_press property, indicating which key was pressed. The array will be encoded in JSON format when data is saved using either the .json() or .csv() functions.

Examples

Displaying a single sequence multiple times

Code

var animation_sequence = ["img/happy_face_1.jpg", "img/happy_face_2.jpg", "img/happy_face_3.jpg", "img/happy_face_4.jpg"];

var animation_trial = {
    type: jsPsychAnimation,
    stimuli: animation_sequence,
    sequence_reps: 3,
    frame_time: 300,
    prompt: '<p>Watch the faces.</p>',
};

Demo

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