Constrain Loop Randomization in OSWeb

Angelina16

Hello,

I am preparing a lexical decision task to be run online and I want to make sure that there will never be more than 4 words or pseudowords presented in a row. Does anyone know how to do that in OSWeb (so without python inline code and mindist funstion)

Thank you!

sebastiaan

Hi Angelina,

The only way I can think of is to use an inline_javascript ithat uses a counter (repetition ) to keep track of how often a particular value is repeated for, in the example, the variable condition . And then you can use a run-if statement to skip all items in the trial sequence when repetition exceeds a certain value. Conversely, a repeat_cycle is run only when it exceeds this value.

It's not very elegant, but it should do the trick in most scenarios!

Cheers,

Sebastiaan

if ((typeof(vars.previous_condition) !== 'undefined') && (vars.previous_condition === vars.condition)) {
    vars.repetition += 1
} else {
    vars.repetition = 0
}
console.log('previous: ' + vars.previous_condition + ' current: ' + vars.condition + ' repetition: ' + vars.repetition)
vars.previous_condition = vars.condition



constrain.osexp

Angelina16

Thank you so much Sebastian! This soulution works perfectly for my experiment!!

Yuyanxue

Hi Sebastiaan,

I have tried this inline_javascript that you suggested to Angelina with the offline version of Opensesame, but it did not work (No module named inline_javascript). I assume this javascript only works for OSWeb. Is there similar code that can be used for inline_Pythonscript?

I found this discussion from 2013 (https://forum.cogsci.nl/index.php?p=/discussion/310/solved-pseudorandom-with-lexical-decision) and step 8 here (https://kvonholzen.github.io/Tutorials_Open_Sesame_Lexical_decision.html#step_8:_pseudorandomize_the_order_of_trials). But these two solutions do not look as straightforward as the one for OSWeb.

I am attaching my unfinished experiment. For example, in subblock 1.1, I would like to pseudo-randomize the trails to keep sequences of expected ‘yes’ (or 'no') responses to no more than three in a row. Is there an essay way to implement this?

Thank you so much in advance!

Best regards,

Mengzhu

Visual_LDT_try.osexp

sebastiaan

Hi Mengzhu,

The solution described in this post is for OSWeb (the online runtime of OpenSesame), which doesn't support OpenSesame's normal pseudorandomization functionality. That makes it a bit complex.

But if you want to run your experiment on the desktop, you can make use of loop constraints, which is much easier.

For example, in subblock 1.1, I would like to pseudo-randomize the trails to keep sequences of expected ‘yes’ (or 'no') responses to no more than three in a row.

Let's say that you have a variable expected_response , then you could add the following constraint to the end of the loop script:

constrain expected_response maxrep=3

See also:

• https://osdoc.cogsci.nl/3.3/manual/structure/loop/#pseudorandomization

Hope this helps!

Cheers,

Sebastiaan

Yuyanxue

Thank you. It worked perfectly!