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Randomly present all blocks and then in a reverse order

Hi all,

OS (e.g. Win10): Win10
PsychoPy version (e.g. 1.84.x): 1.90.1
Standard Standalone? (y/n) If not then what?: y
What are you trying to achieve?:
I have 5 blocks and each block contains 100 trials. I want to repeat all my block twice, which results in 10 blocks in total. I’d like to randomize the first 5 blocks and then present all blocks in reverse order for the same participants. Namely, if the first 5 blocks are 3, 2, 4, 5, 1 (randomly chose order), then I’d like my experiment to have the 10 blocks like 3,2,4,5,1,1,5,4,2,3
What did you try to make it work?:
My initial guess is that, with a ‘random’ looptype Capture
and only repeat all my blocks once, I will get some kind of output of which order does it pick up. Then I can assign it to another loop. However, I am not able to figure out how can I do that.

This would need to be done in code. Insert a code component. In its “begin experiment tab”, put something like:

import copy

# create a list of filenames (use your actual names of course):
blocks = ['con01.xlsx', 'con02.xlsx', 'con03.xlsx', 'con04.xlsx', 'con05.xlsx']

# randomise it:

# make a copy and reverse it:
blocks_2 = copy.copy(blocks)

# add it to end of the original list:

# check that it does what you want:

Now your blocks loop:

  • no longer needs to be connected to a conditions file (as the list of blocks is held in code now), and
  • you’ll need to specify the nReps to be 10 so you get the correct number of blocks, and
  • it should be “sequential” rather than “random” now (not that it would make much difference here I guess).

Lastly, in your inner trials loop, put this in the “conditions file” field:


This takes the next filename in order from the blocks list.

Thank you @Michael, the above code and setting solved my block order problem. However, as a result, I have to disconnect to a condition file, as you said. However, in my previous condition files, I also put other variables only for the start of each block, because I want to show participants some reference stimuli before each block. So that I had condition files like this:

I want to link them to each block again. Could you kindly help me with this issue?

Thank you a lot.

Hi @Michael I think I got a fairly detailed question than my last reply.

I have 5 blocks in total and want to present them 10 times, first 5 times in a random order, next 5 times in reverse order. In instr2, I created a code component and wrote your code down

import copy

# a list of filenames 
blocks1 = ['condition0.8.xlsx', 'condition0.7.xlsx', 'condition0.6.xlsx', 'condition0.5.xlsx', 'condition0.4.xlsx']

# make a copy and reverse it:
blocks_2 = copy.copy(blocks1)

# add it to end of the original list:

Also, I set the trials properties like this

For each condition excel file, I add 3 references stimuli pictures in row 2-4,

I only want to present the reference stimuli (in row 2-4) once before each block.

To achieve this, I added another loop trails_ref, see my new structure of the experiment:

Then, I set trails_ref loop property:
The problem is that trails-ref and trials does not take the same condition file when I run the code.

It seems that trials_ref and trails loop are independent from each other. Is there any way to let trail_ref take the first 3 rows of one condition file, and then trail take the rest of the stimuli from the same condition file?

Thank you so much in advance.