I’m trying to put two or three pictures on the screen at the same time. My question surrounds the location of the picture. Ideally, I want the pictures to be in random locations. Subjects will be using a mouse to select the picture.
Currently, I have the pictures locked to one particular location, but as mentioned, I’d like them to be in random locations. My issue is that when I change the locations to variable, the pictures tend to overlap one another. Is there any way to do this besides creating multiple events per picture w/ different screen locations?
The way to randomize the location on the screen is with Screen Location Trial Variables. You need to randomize with no replacement. Your correct response must also be defined by the position of the stimulus.
If you want to ignore invalid mouse clicks, you’ll need to set up more than one response (three responses if you are showing three pictures at once). Each of your events will need to specify a unique one of these responses as its own correct answer in order to specify the stimulus location as relevant to the mouse input plug-in.
the participants will use the mouse to detect the angry facial expression
Superlab has to:
(1) present 16 stimuli simoultanously in a randomized order
(2) stimuli may not overlap
(3) relevant event: found angry expression and response time
Additionally, several trials are needed, each time with a different stimulus set (15 neutral + 1 angry facial expression).
Your design can be implemented using the trial variables feature. You’d create a trial variable with 16 locations and tell SuperLab to pick “levels” of this variable at random.
