RandomizeNoMoreThan

[Elise]

Hi Jeremy,

I know that when I want to constrain multiple conditions to appear only a certain times in a row, I can use the randomizeNoMoreThan function:

Sequence(randomizeNoMoreThan(anyOf(startsWith("con-"), startsWith("incon-"), startsWith("neu-"),3)))

But is there any way that I can pseudorandomize conditions such that only one condition is constrained to appear three times in a row? E.g., I want the congruent condition (“con-“) to appear not more than three times in a row, but I don’t want to apply that contraint to the incongruent and the neutral condition.

I would be greatful for any help!

Best,
Elise

[Jeremy]

Hi Elise,

The randomizeNoMoreThan function is based on exact match between labels: it will only make sure that, say, con-tst is not followed by more than two other con-tst, however, it will be OK with a sequence like con-tst–con-fil–con-tst–con-fil

You can minimally edit it, so that you can pass it predicates after n to identify which trials from the set it should target:

function RandomizeNoMoreThan(predicate,n,...filters) {
    this.args = [predicate];
    this.run = function(arrays) {
        let moreThanN = true;
        let order;
        while (moreThanN){
            order = randomize(predicate).run(arrays);
            moreThanN = false;
            let previousType = "";
            let current_n = 0;
            for (let i = 0; i < order.length; i++){
                let currentType = order[i][0].type;
                if (currentType==previousType || (filters.length&&filters.filter(f=>f(currentType)).length)){
                    current_n++;
                    if (current_n > n){
                        moreThanN = true;
                        break;
                    }
                }
                else{
                    current_n = 1;
                    previousType = currentType;
                }
            }
        }
        return order;
    };
}          
function randomizeNoMoreThan(predicate, n, ...filters) {
    return new RandomizeNoMoreThan(predicate,n, ...filters);
}

Then you can use it like this:

Sequence(
    randomizeNoMoreThan(
        anyOf(startsWith("con-"), startsWith("incon-"), startsWith("neu-")),
        3,
        startsWith("con-")
    )
)

and it will make sure that you have no subseries of more than three trials whose label starts with con- in a row (it will allow for 3+ series of trials with any other labels)

Jeremy

[Elise]

Thank you very much, Jeremy! It worked perfectly!

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