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Intentional Binding Paradigm - random starting position

Hello everybody,

I hope someone can help me.
I'm trying to create an Intentional Binding Paradigm, in which a clock is displayed and participants must judge the occurrence of a keypress/tone.
I was able to make the clock hand rotating, but I'm having problems to make it start from a specific position in every trial (i.e., one of the 12 five-minutes intervals represented on the clock).
There's my code (xc, yc = 0 are the coordinates of the center of the clock):

Thank you in advance!!


  • Hi,

    You can add a constant angle to the computation of dx and dy. For example:

    dx = arm_length*cos(radians(time+start_angle))

    Just make sure that you set the angle before you enter the loop, e.g. with numpy's linspace:

    import numpy as np
    start_angle = np.linspace(0,2*np.pi,12) # I think that is right, but check it whether this gives you the 12 positions you want.

    Hope this helps,


  • Thanks a lot, Eduard!

  • Hello again,

    I'm dealing with a new problem that I'm not be able to solve alone.

    I was able to finish my Intentional Binding Paradigm, but now I'm trying to make it "social": in other words, two participants do the same task together and they have to press a key during the same task.

    Ideally, I would try to collect responses from two different keyboards (each used by one participant), in every trial.

    Really hope someone helps me!


  • What exactly is the problem?two keyboards are no problem. Having two interactive participant is a little tricky. You can find workaround by using unique keys for each one and infer based on the keypresses what happened. To make them properly interactive and unique, in a way, is more difficult and I don't really know how to solve it.


  • Thank you, Eduard.

    I'm writing again as I'm struggling with a new issue: I want a clock hand rotating for 2560 ms for each trial. I read the previous discussions about this topic as well as to change the values both of the step size and the delay according to the refresh rate of my computer screen, but nothing seems to work.
    Moreover, the rotation time is never stable across trials (e.g. every trial returns a different time rotation).

    I post my code below, any help would be really appreciated.

    Best, Cecilia

  • edited January 12

    Hi Cecilia,

    can you paste your code as text? Otherwise I have to manually type it. If you copy the code between each three tildes (~) , it will be formatted as code (see Markdown)


  • Hi Eduard,
    please find attache the .txt file with the code.

    Thank you in advance!

  • Hi Cecilia,

    Can you also attach the files that are necessary to run the experiment? (and include the variables that were defined outside that script that you attached).



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