Randomize trial in a sequence and repeat the same sequence two times

alfomaglia

Hi, I have a sequence with 4 items. I need to randomize items in the sequence e show the sequence two times. For example, if my trials are "A, B, C, D" I need to randomize them (e.g. B, C, A, D) and then show this sequence two times (B, C, A, D, B, C, A, D).
In OpenSesame I set an experimental loop with 4 cycles in random order. Then, how can I repeat the same sequence two times?

sebastiaan

Hi,

That's an interesting scenario. There are multiple ways to solve it, but here's what I would do. First, in your loop, define your condition variable in terms of other variables: condition0, condition1, etc. Keep a sequential order, and set repeat to 2:

Then, before the loop, insert an inline_script in which you define the variables condition0, etc. such that they correspond to your conditions ('A', 'B', 'C', and 'D) in a random order.

import random

conditions = ['A', 'B', 'C', 'D']
random.shuffle(conditions)

var.condition0 = conditions[0]
var.condition1 = conditions[1]
var.condition2 = conditions[2]
var.condition3 = conditions[3]

Do you see the logic here?

Cheers,
Sebastiaan

alfomaglia

Hi Sebastian,
Thanks for your response. I'm not very good in Python, so I'll show you my experiment:

On the left you can see the experimental sequence, then my experimental loop (is that correct?). Then i wrote a inline_script as you told me:

Could you help me in a more specific way?

Thanks a lot

eduard

Hi,

What exactly is the problem? Your script and structure seem to be fine. (Maybe you could move your script for the run to the prepare phase of your inline_script). Are there any error messages?

Eduard

alfomaglia

The problem is that trials are not randomized. It shows times 25, 35, 45 and 55 and then repeats.

eduard

Oh, I see. Well, this is because you do randomize only your condition variable but not the durations of the conditions. They are hardcoded.

You can try coding all your variables in a similar way:

import random

order = [1,2,3,4]
conditions = ['A', 'B', 'C', 'D']
durations = [25000,35000,45000,55000]
random.shuffle(order)

# the conditions
var.condition0 = conditions[order[0]]
var.condition1 = conditions[order[1]]
var.condition2 = conditions[order[2]]
var.condition3 = conditions[order[3]]

# the durations
var.durations0 = durations[order[0]]
var.durations1 = durations[order[1]]
var.durations2 = durations[order[2]]
var.durations3 = durations[order[3]]

# etc..

Alternatively, you have to add another inline_script to the trial sequence and in that one set variables depending on the condition you are in.

Does that make sense?

Eduard