Millisecond Forums

Multimodal trials

https://forums.millisecond.com/Topic1833.aspx

By AlexR - 8/20/2008

Hey hey,

I'm new to working with Inquisit. I have used the sample scripts to create what I want, but I have a question about creating trials that present more than one kind of stimulus, ie text AND sound.

I'm running an experiment with large trialdurations, 50s. They only need to pay attention for about 10 seconds of that and the rest is recovery time (odour experiments). I want a warning beep when they have to pay attention to the next instruction, so do I need to set that up as a separate trial element? Or can I make it one of the / stimulusframes components in the existing text trial element? I'm just trying to work it out in terms of keeping my trials randomised. I've looked and looked, but I figured it was best to just ask.

Loving this program though, making life much easier!

Alex
By Dave - 8/21/2008

Hi Alex,

Inquisit can present stimuli of different modalities in one single trial. Make sure the stimuli are all defined in your script (using the <text> and <sound> elements) and then let the <trial> element present them in whatever order and at whatever time you wish by using the /stimulusframes or /stimulustimes attribute. For example:

<trial mytrial>
/stimulustimes=[1=someinstructions; 10000=payattentiontext, payattentionsound; 20000=somemoreinstructions]
/ validresponse=("a", "b")
/
correctresponse=("a")
/ trialduration = 50000
</trial>


This trial presents a text stimulus right at the onset (someinstructions), after 10 seconds a message to pay attention is presented on screen (payattentiontext) along with a corresponding sound (payattentionsound), 20 seconds into the trial, additional instructions appear on screen (somemoreinstructions).

You might also want to check out the /responsetime or /responseframe attributes to tell Inquisit when to register responses in your trials.

Hope this helps,
~Dave