When are stimuli sent to the user's computer?
I am working on an online response-time experiment where the subject is shown approximately 50 photographs (1 per trial), and had a question: are all the stimuli sent to the user's machine during the initial loading stage of the experiment, or are they sent at the moment when the corresponding trial comes up?
My thinking is that if all the stimuli pictures are loaded at the outset, then a higher number of concurrent users would increase the initial loading stage (which is not too crucial), but should not impact the timing of the experiment too much once its in progress. On the other hand if the stimuli are sent on a trial by trial basis then a larger number of concurrent users might throw off the timing within the experiment, which would be a bigger problem for my experiment. Therefore, depending on when the stimuli are actually sent, I may have to gate the number of concurrent participants.
Thank in advance!
Comments
Hi,
The simple answer is that it depends on your javascript, i.e. how you've written your code.
Did you use a toolbox?I suspect you used OSWeb (because in your question you don't clarify it and we're in the same forum-platform). But keep in mind that JATOS and OSWeb are different things.
I know that jsPsych for example has a pre-load function . I'm not sure what OSWeb does. If you wrote your study with no toolbox, then it's up to you to decide when to load your images.
Best
Elisa
Hi Elise, thank you for replying. I made the experiment using Opensesame and OSWeb.
Then you should ask them, as I really don't know. @Daniel might be able to help
Hi @veskerm,
Osweb downloads all stimuli at the start of the experiment. You can see the progress bar after you have clicked on osweb's canvas that starts the experiment. So when a trial starts, all assets should already be present on the user's machine.
Thank you for clarifying Daniel!