**OS Win10

**PsychoPy version 1.84

**Standard Standalone

Hello,

I’m struggling with an experiment for while, tried several approaches, but none of them was successful (not independently from the fact that I’m a novice to Psychopy).

The experiment shortly: the goal is to present 10 facial images out of 30 randomly, and pair them with either a negative or a positive prime (i.e. faces will be preceded with either a negative or a positive image.)

So, basically I have three lists: one containing 5 positive, an other with 5 negative, and a third with 30 facial images. I’d like to pair 5 random faces with ALL of the negative images once, another 5 random faces with ALL the negatives. Negative and positive conditions should be randomized.

I. First I tried to use a code found here on the forum ( shuffle(all_rows) ). In builder I set the selected rows option to use the first 5 rows (to pair the first 5 faces from the randomized list with the primes (I made two separate routines for the conditions, but I will get back to this later). The problem with it was that when my xlsx file containt three colums, all them will be randomized, so sometimes I get blank screen instead of primes.

Question: is it possible the shuffle only one column of an excel sheet instead of shuffling all? Or is it possible to use multiple sheets for the same loop?

II.I tried to put the the conditions (negative, positive) in two separate routines and make a loop around them to chose randomly between to two until all possible pairings have been shown. My main problem was that prime/face pairings seem to be fixed, but it should show all possible pairs (if a face is preceded by a negative prime once, at the next repetition is should be another one from the negative list). So 5 repetition for each face, 5 repetition of each prime.

Question: how can I present all possible prime/face combinations randomly?

III. I also tried to split the priming routine to separate prime + face routines. This also failed because I was unable to break to prime loop befor the 5 repetitions was finished (I got 5 primes, THEN 5 faces). When I set to repetion times to one, and made an outer loop with five repetitions, it seemed I lost control of whether the same prime is repeated or not (I also had the intention to make another outer loop to choose randomly between negative and positive conditions each made of two routines, but at that point I gave up).

Ultimate question: can any of my approaches lead to success?

Sorry if I made nonsense questions. I’ll try to rephrase if necessary.

Any advice will be appreciated!

many thanks