Reaction times and button presses

URL of experiment: Pavlovia

Description of the problem: Hi guys, I have now seen the same issue with 4 participants and I am super confused as in what might be happening. I am doing my experiment online and I am using prolific as my recruitment service. For some reason for some of the participants their reaction times and button presses are not recorded. I have no idea why this might be happening. If you have access to my data check subjects 63, 73, 56 or 26. No idea what’s happening there but I’ve now lost 5 subjects and one of them got really angry at me because I assumed they just didn’t do the task.

One subject reported the screen locking during the experiment. Any insights on this will be super helpful.

Hi @antoniyaaboyanova, you have to make the experiment public so other users can access it.

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I made it public now. If you can give me any insight on the issue that would be great! Thank you. May be you can tell me if I can extract any information from the log file that suggests what the participants might have been doing. Best, Antoniya

Hi @antoniyaaboyanova, so from a first look you can see that the logs of some of the incomplete participants contain a lot of “Mouse” data entries when you don’t even use a mouse for the responses. My guess is that these participants used a touch screen or their mouse to try to give responses and did not use the arrow keys. Others did not respond at all and only clicked “space” when starting a new block. Sometimes they took multiple minutes after they were asked to press space to actually press space. So they probably not paying attention to the experiment, just waiting for it to finish They probably took so long because every single trial was over 2 seconds for them (maximum duration of trial when no key is pressed). Alternatively, there might be a bug where key presses are not registered or are registered as mouse inputs, but I’ve never heard of something like this. Did you ask your participants about how they completed the experiment? Specifically, if they used the arrow keys and what kind of device they used?

To avoid something like this in the future, you may want to design your experiment in a way that it does not just go by if participants do nothing :smiley:

Anyway, you definitely won’t be able to recover any data from the logs because there is nothing there.

This is how you read the log file if you want to have a look yourself:

  • Open it in a text editor
  • in the left column you see the seconds since the experiment was started
  • in the two right columns you see what happened at this point in time
  • every entry starting with “DATA” is a response that the participant gave and contains details on what that response was (Mouse, Keyboard, key, mouse position, etc.)

Some other tips I thought of when looking at your experiment:

  • You don’t have to have two keyboard components for two keys. One component can have both. This makes it easier to analyse the data later
  • Using prolific, you can send the ID of the participant to pavlovia without having the participant enter them. This is less prone to error. It’s called using URL parameters and can be configured on the page of your study in prolific.
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Thank you so much for your input! It was super helpful! :slight_smile: