Millisecond Forums

Ok, that makes sense, I'll give it a try and see how it goes. Thanks again Dave! :)

+x

 

raven - 5/16/2023

Thanks Dave,

The no response part of the script works great.

For the second part though, I would like stimuli that doesn't change the score randomly mixed in with the other stimuli that do change the score, so are you saying that I can create another <trial>? How would I make those stimuli be randomly presented with the other stimuli?

Yes, create another trial. Let's call it the "distractor" trial and the one that changes the score the "experimental" trial. Then sample these trials randomly in your block, at whatever experimental to distractor trial ratio you want.

E.g.

<block example>
/ trials = [1-100 = noreplace(experimental, distractor)]
</block>

would run 50 experimental trials and 50 distractor trials in random order, for a total of 100 trials.

<block example>
/ trials = [1-100 = noreplace(experimental, experimental, experimental, distractor)]
</block>

would run 75 experimental trials and 25 distractor trials in random order, i.e. a 3 to 1 ratio.

Thanks Dave,

The no response part of the script works great.

For the second part though, I would like stimuli that doesn't change the score randomly mixed in with the other stimuli that do change the score, so are you saying that I can create another <trial>? How would I make those stimuli be randomly presented with the other stimuli?

+x

 

raven - 5/14/2023

To explain better, instead of using the mouse for input, I'd like to use keyboard input 'e' if participants think a particular stimulus (from cstim) will result in a score increase, or 'i' if they think it will result in a score decrease (from icstim), but if no input is received, then the score will decrease (as per previous post).

Also, is it possible to include a pool of stimuli that don't result in any change to the score?

I appreciate your help!

> I've implemented a timeout, so is it possible to make the score reduce by 10 points if the participant does not respond within that period?

/ ontrialend = [if (trial.example.response == 0) {
values.score -= 10;}
]

> Also, is it possible to include a pool of stimuli that don't result in any change to the score?

Sure, just set up and run a <trial> that displays these stimuli and does not change the score.

To explain better, instead of using the mouse for input, I'd like to use keyboard input 'e' if participants think a particular stimulus (from cstim) will result in a score increase, or 'i' if they think it will result in a score decrease (from icstim), but if no input is received, then the score will decrease (as per previous post).

Also, is it possible to include a pool of stimuli that don't result in any change to the score?

I appreciate your help!

I've implemented a timeout, so is it possible to make the score reduce by 10 points if the participant does not respond within that period?

+x

 

raven - 5/10/2023

Thanks for explaining the logic, that clears things up.

Also, just to confirm, does the 'noreplace' attribute mean that a particular stimulus will only be shown once, as opposed to multiple times?

noreplace means items are sampled randomly without replacement. If you have a stimulus with 5 items and sample from that stimulus 5 times, then each item will appear exactly once. If you sample more than 5 times from the stimulus, then obviously some or all items will have to repeat.

Thanks for explaining the logic, that clears things up.

Also, just to confirm, does the 'noreplace' attribute mean that a particular stimulus will only be shown once, as opposed to multiple times?

+x

 

raven - 5/10/2023

Thanks Dave, that makes sense.

So I guess there would be no way to ensure that each participant gets 6 wins and 4 losses when using randomisation of stimuli.

What if the stimuli aren't randomised and are drawn from a given set that all participants will see (e.g.: / items = ("A", "E", "I", "O", "U", "B", "C", "D", "F", "G")? In this instance it should ensure the required ratio of wins and losses. But, following on from that, can the order of the stimuli be randomised for different participants, ensuring the same win/loss ratio?

I hope that makes sense. :unsure:

Randomization of stimuli has nothing to do with it. You cannot know how often a given participant will guess correctly. It's the participant's choice how they respond and it's not under your control!

Suppose you run 20 trials and use the deck of 10 cards model (i.e. /replace = false for the list, 6 "win" cards, 4 "loss" cards).
Participant A makes 3 correct guesses. There is no way for this participant to achieve a 60/40 win-loss ratio, and the realized ratio might be anything from 3 wins / 0 losses to 0 wins / 3 losses.
Participant B makes 13 correct guesses. In the deck of cards model, they'll have an exact 6/4 split for the 1st 10 correct guesses. But what about the remaining 3? Those could again be anything between 3 wins / 0 losses and 0 wins / 3 losses. Or, across all 13 guesses, anything between 9 wins / 4 losses and 6 wins / 7 losses.

Thanks Dave, that makes sense.

So I guess there would be no way to ensure that each participant gets 6 wins and 4 losses when using randomisation of stimuli.

What if the stimuli aren't randomised and are drawn from a given set that all participants will see (e.g.: / items = ("A", "E", "I", "O", "U", "B", "C", "D", "F", "G")? In this instance it should ensure the required ratio of wins and losses. But, following on from that, can the order of the stimuli be randomised for different participants, ensuring the same win/loss ratio?

I hope that makes sense. :unsure: