Computer mouse-tracking

[rhododendron]

Dear Jeremy,

I was wondering whether it is possible to implement computer mouse-tracking by using Ibex. As well as that, are you aware of any studies that compare Ibex results with software used for in-lab RT experiments? There is literature pointing to the fact that JavaScript packages used for measuring RTs online might introduce some constant lag of approx 25ms to the measured RTs (de Leeuw, J. R., & Motz, B. A. (2015). Psychophysics in a Web browser? Comparing response times collected with JavaScript and Psychophysics Toolbox in a visual search task. Behavior Research Methods. doi:10.3758/s13428-015-0567-2). I am curious to know whether this applies to Ibex as well and whether the contant is larger or smaller.

Thank you so much for your help!

Best,
Ana-Maria

[Jeremy]

Dear Ana-Maria,

There actually is a MouseTracker element in PCIbex, but it is not documented yet. Let me know if you’re interested and I’ll start writing the documentation. The only caveat is that it can quickly produce massive results files (because it stores coordinates every tens of milliseconds) so you want to make sure you only track during informative periods.

I’m not aware of studies comparing RTs online vs in-lab (not to say there aren’t, see reference in your own message!), but since (PC)Ibex is based on javascript, it will come with the same lag that is described in the paper you cite. Depending on the nature of your investigation, a 25ms lag may or may not be a serious concern. Florian Schwarz and I for example have conducted online visual-world experiments where participants select one of two images after listening to a sentence; RTs were of the order of seconds, and we found significant differences across conditions, in the order of hundreds of milliseconds. You can also check this message by Florian on the forums for references about work from David Embick’s lab on lexical priming.

Jeremy

[rhododendron]

Thank you so, so much for your answer! It was very helpful and I am so glad that there is a MouseTracker element in Ibex, since I would like to use that for my Master’s thesis. The point of the experiments that I will set up would be to get as close as possible to the visual world paradigm. In that sense, it would be beyond wonderful if there was some documentation available.

I am very thankful for your support and help!
Have a nice weekend,

Ana-Maria

[Jeremy]

Then you might also be interested in the EyeTracker element, although it’s important to note that it’s still very much an experimental feature and I don’t know that anyone has collected actual data with it yet (as noted on the linked page, one problem is cross-browser compatibility, which seriously compromises the recruitment of paid participants).

I’ll try to get to the documentation in the coming days, but you can already use the MouseTracker element: it is included in PennController, there’s just no documentation entry for it at the moment. Here’s an example of how to use it in one trial:

newTrial(
  newButton("Start").print("center at 50vw", "middle at 50vh").wait().remove()
  ,
  newMouseTracker("mouse").log().start()
  ,
  newCanvas("left", "40vw", "40vh").css("background","red").print("center at 25vw", "middle at 50vh"),
  newCanvas("right", "40vw", "40vh").css("background","blue").print("center at 75vw", "middle at 50vh"),
  newSelector("choice").add( getCanvas("left") , getCanvas("right") ).log().wait()
  ,
  getMouseTracker("mouse").stop()
)

Jeremy

[Jeremy]

The MouseTracker element is now documented here.

Jeremy

[Author]

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