Ratingscale Forced Choice

Coding
1

Hello Ladies and Gentlemen,

in my experiment I’m using the following ratingscale.

r_scale = visual.RatingScale(win,
                            name='example_rs',
                            labels=['-','+'],
                            marker=(visual.TextStim(win, text = '|', units = 'norm', color = 'red')),
                            scale=None, 
                            low = -1, high = 1, 
                            choices = ['-','+'],
                            markerColor = 'red',
                            autoLog = str(autolog_rs),
                            markerStart = 0.5,
                            stretch = rs_stretch,
                            noMouse = True,
                            minTime = 0
                            )

As of now the scale is navigated using the arrow keys and the marker starts in the center of the dichotomous scale. You have to press enter to save the rating.

As of now if the participant does not move the marker, ‘-’ will be saved as the response.

I want that the participant has to lock in one of the answers first using the arrow keys. Is there an inbuilt function for this or do I have to use an if condition that records pressed keys?