Avarege reaction times in Dot Probe

AnaToma

Hello,

I am part of a research team and we used OpenSesame in order to build our Dot probe experiment.
Could you please tell us based on what formula are the average reaction times in the output files calculated?

Thank you so much!

sebastiaan

Hi Ana,

The avg_rt simply is the mean of the RTs collected so far since the last reset of the feedback variables. But I'm guessing you're not really asking about the formula for calculating a mean, but are confused about what happens in your experiment. What exactly is the confusion?

Cheers!
Sebastiaan

AnaToma

Hello,
Thanks for your answer.

We’ve built a dot probe experiment for our research project, assessing attention bias to appetitive stimuli. We have already recorded data from several participants and we noticed that our reaction times are way larger than the ones we’d expect based on similar studies. We also noticed that our output files only display the average reaction time for every trial, but we’d need to know the exact response time per trial. Could we extract the response time/trial based on the average reaction time in the output files? If so, could you please help us with the formula for computing it?
Would it be possible for our reaction times to include the time needed for the display of the stimuli and fixation crosses, apart from the actual reaction times?
Thank you!

eduard

Hi,

I think there are two issues:

1)

We have already recorded data from several participants and we noticed that our reaction times are way larger than the ones we’d expect based on similar studies

This could have several reasons. If you share the structure of your experiment or, better yet, your experimental file, we could check what might cause this delay.

Would it be possible for our reaction times to include the time needed for the display of the stimuli and fixation crosses, apart from the actual reaction times?

Maybe, but again, I would need to see your experiment to make sure that this is what happens.

2)

We also noticed that our output files only display the average reaction time for every trial, but we’d need to know the exact response time per trial

Now, I am confused. The average reaction time for every trial should be the same as the exact response time per trial, provided that there is only one response per trial. Or do you mean the accumulated average reaction time for all trials up to the current one?
In any case, normally, there should also be a variable response_time in your log file that has the individual response times per trial (or per call of the keyboard response item). Is this variable present in your logfile? ALso here, if you share one file with us, we could also have a look.

Could we extract the response time/trial based on the average reaction time in the output files?

If you only have the average response times, then you can't retrieve individual responses anymore, I am afraid. Again, check out your logfile, the individual times could be stored in another variable.

Hope this helps,

Eduard

AnaToma

Hello,

Thanks for your answer.
I have attached here the Google Drive access link to our dot probe as well as some of our output files.
https://drive.google.com/file/d/19AINQx2xtZKOrvhCmbZdwWw6jwqLzCYF/view?usp=sharing

The problem is that, unfortunately, our log files don't have the response_time variable.
Is there any solution to this problem?

Thank you!

sebastiaan

Hi Ana,

In this experiment, you have disabled the option to log all variables, instead manually selecting a few variables, not including response_time. So that's why response_time is not in the log file.

I would also take a good look at the way that responses are collected in the new_loop_2 and new_loop_3 items. This is quite an odd construction, and I'm not sure what it's supposed to do. Are you sure that the experiment functions exactly as you want it to?

Cheers!
Sebastiaan