The same-different plugin displays two stimuli sequentially. Stimuli can be images or HTML objects. The subject responds using the keyboard, and indicates whether the stimuli were the same or different. Same does not necessarily mean identical; a category judgment could be made, for example.
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.
|stimuli||array||undefined||A pair of stimuli, represented as an array with two entries, one for each stimulus. A stimulus can be either a path to an image file or a string containing valid HTML markup. Stimuli will be shown in the order that they are defined in the array.|
|is_html||boolean||false||If the elements of the
|same_key||numeric or string||'Q'||The key that subjects should press to indicate that the two stimuli are the same.|
|different_key||numeric or string||'P'||The key that subjects should press to indicate that the two stimuli are different.|
|timing_first_stim||numeric||1000||How long to show the first stimulus for in milliseconds. If the value of this parameter is
|timing_gap||numeric||500||How long to show a blank screen in between the two stimuli.|
|timing_second_stim||numeric||1000||How long to show the second stimulus for in milliseconds. If the value of this parameter is
|prompt||string||""||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 to press).|
In addition to the default data collected by all plugins, this plugin collects the following data for each trial.
|stimulus||string||An JSON-encoded array of length 2 containing either the path to the image file or the string containing the HTML formatted content that the subject saw for each trial.|
|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 second stimulus first appears on the screen until the subject's response.|
|answer||string||The correct answer to the trial, either
-1, then the following data is also collected:
|rt_stim1||numeric||The response time in milliseconds for the subject to continue after the first stimulus. The time is measured from when the first stimulus appears on the screen until the subject's response.|
|key_press_stim1||numeric||Indicates which key the subject pressed to continue. The value is the numeric key code corresponding to the subject's response.|