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Attention Bias Task Implementation

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PsychoPy version (e.g. 1.85.1):

I am trying to implement an attention bias measurement task. Firstly i have to display a cross image. Secondly, i have to present two face images (one angry and one neutral), side by side. Thirdly, i have to display the cross image again, only that the cross image has to appear in 50% of the trials in the place of the neutral face and in 50% of the trials in the place of the angry face. I have 16 face pairs and i run the set 4 times, for a total of 64 iterations.

I have the experiment running in psychopy. However, i want the pairs of faces to be placed randomly (at the time i am writing this i only managed to display the angry faces on the left side and the neutral faces on the right side). How would i go about in builder or the excel that contains the variables to randomize the placement of faces and condition the cross to appear 50% in the place of the angry face and 50% in the place of the neutral face?

My excel variable file is arranged as follows:
picture_left------------left_pos----picture_right-----right_pos–probe—probe_pos
picture1-disgust.jpg (-0.5, 0) picture1-neutral.jpg (0, 0.5) probe.jpg (0.5, 0)
picture2-disgust.jpg (-0.5, 0) picture2-neutral.jpg (0, 0.5) probe.jpg (0.5, 0)
picture3-disgust.jpg (-0.5, 0) picture3-neutral.jpg (0, 0.5) probe.jpg (0.5, 0)
picture4-disgust.jpg (-0.5, 0) picture4-neutral.jpg (0, 0.5) probe.jpg (0.5, 0)

Thanks

Hi - you would just double up your conditions files so that all positions are represented as rows. Just copy and paste your above entries and swap over the minus signs.

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Oli

Thank you very much @Oli for your solution. It indeed works, in that the placement of angry and neutral faces is randomised now.
I still have the problem with the cross that follows the faces. I need the cross to replace the neutral face in 50% of the cases and the angry face in 50% of the cases (now it only replaces the angry faces). Moreover, i want the next trial to begin only when the correct key is pressed (e.g. if the cross is on the left and the participant presses the left key, the next trial begins; if the oposite key is pressed, the next trial doesn’t begin until the participant presses the appropriate key).
I am attaching the “psyexp” file and the “conditions” file to see what this is about more clearly. Please note that the pictures in the “picture_left” column are all the angry faces and the faces in the “picture_right” column are the neutral faces (they are paired, because i have to show the same person with the two emotions displayed).
Thank you very much, againABM_EXP.psyexp (19.0 KB)
Stimuli.xlsx (9.4 KB)

There should be a row for each trial - so you’ll need to now copy everything and change the probe position attribute so that it matches the neutral face position.

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Oli

Thank you very much @Oli, that has been very helpful