jsPsych/docs/markdown_docs/plugins/jspsych-visual-search-circle.md

jspsych-visual-search-circle plugin

This plugin presents a customizable visual-search task modelled after Wang, Cavanagh, & Green (1994). The subject indicates whether or not a target is present among a set of distractors. The stimuli are displayed in a circle, evenly-spaced, equidistant from a fixation point. Here is an example using normal and backward Ns:

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
target_present	array	undefined	Array of boolean values indicating if the target will appear in the search array. The length of the array determines the number of trials.
set_size	numeric	undefined	Array of integers. Each element represents the number of items in the search array for the corresponding trial.
target	string	undefined	Path to image file that is the search target.
foil	string	undefined	Path to image file that is the foil/distractor.
fixation_image	string	undefined	Path to image file that is a fixation target.
target_size	array	[50, 50]	Two element array indicating the height and width of the search array element images.
fixation_size	array	[16, 16]	Two element array indicating the height and width of the fixation image.
circle_diameter	numeric	250	The diameter of the search array circle in pixels.
target_present_key	numeric	74	The key to press if the target is present in the search array.
target_absent_key	numeric	70	The key to press if the the target is not present in the search array.
timing_max_search	numeric	-1	The maximum amount of time the subject is allowed to search before the trial will continue. A value of -1 will allow the subject to search indefinitely.
timing_fixation	numeric	1000	How long to show the fixation image for before the search array (in milliseconds).

Data Generated

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

Name	Type	Value
correct	boolean	True if the subject gave the correct response.
key_press	numeric	Indicates which key the subject pressed. The value is the numeric key code corresponding to the subject's response.
rt	numeric	The response 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.
set_size	numeric	The number of items in the search array
target_present	boolean	True if the target is present in the search array
locations	JSON string	JSON-encoded array where each element of the array is the pixel value of the center of an image in the search array. If the target is present, then the first element will represent the location of the target.

Example