E-prime and eye-tracker. How to synchronize the results?

[Nadia Rohl]

Hello all!

I am about to launch my first eye-tracking experiment using E-prime. 

The experiment itself is quite simple, it's "looking while listening procedure" (Mackey, A., & Marsden, E. (Eds.). (2015).Advancing Methodology and Practice: The IRIS Repository of Instruments for Research Into Second Languages. Routledge.)

The thing I don't know is HOW TO SYNCHRONIZE THE RESULTS of the experiment - RTs (participants will respond by clicking left/right button of the mouse) and eye-tracking data (gaze and fixation). Basically, I have 1 time course and 2 types of responds (1-their clicks and 2-their eye movements), and I don't know how to put them together (neither software, nor method to do so).

Maybe some of you did so and could give me a piece of advice. I would be extremely grateful and happy to hear from you!

Thanks a lot in advance!

[David McFarlane]

Does E-Prime collect both the mouse clicks and the eye-tracking data?
If so, does the eye-tracking data include .RTTime values? The mouse
responses should also include .RTTime values. In that case you may just
compare those (.RTTime is time in ms from the start of the experiment
session).

If instead you have external equipment that gathers the eye-tracking
data, then things get a bit more complicated and I will leave the answer
to others.

---------------
David McFarlane
E-Prime training online:
http://psychology.msu.edu/Workshops_Courses/eprime.aspx
Twitter: @EPrimeMaster (https://twitter.com/EPrimeMaster)

On 2016-03-10 5:51 AM, Nadia Rohl wrote:
> I am about to launch my first eye-tracking experiment using E-prime.
> The experiment itself is quite simple, it's "looking while listening

> procedure" (Mackey, A., & Marsden, E. (Eds.). (2015).*Advancing Methodology

> and Practice: The IRIS Repository of Instruments for Research Into Second

> Languages*. Routledge.)

[Ines Anton-Mendez]

I do it with Excel. I export the E-merged data to text, then work in Excel to synchronize (with voice onset times measured outside of EPrime) and align the eye-movement data from all the participants with respect to their own unique VOTs. In Excel, I use formulas to create the timeline (Vlookup to bring disparate sets of data together, conditionals to find alignment points, arithmetic formulas to compute timelines).
If anybody else has a more efficient way of doing it, I'd be interested in hearing it.

Inés

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[Nadia Rohl]

Hello David!

Thanks for your reply. E-prime does not collect eye-track.data and that's the reason actually why I have this problem. If only it would do so...

 

четверг, 10 марта 2016 г., 18:08:23 UTC+1 пользователь McFarlane, David написал:

[Nadia Rohl]

Hello Ines! yeah I thought I might do smth like this with Exel and also I hoped that there is more elegant way to do it. Let's wait and see if our colleagues do it more effective. :)

P.S. I am happy to talk to someone who is actually interested in the same things with eye-tracker. Thanks a lot for your reply! 

пятница, 11 марта 2016 г., 1:11:44 UTC+1 пользователь iantonm2 написал:

[JACanterbury]

It will likely depend upon your specific eye tracker. If you're doing eye tracking data collection on one PC and stimulus presentation on another, then there should be an api for the eye tracker that you can call from e-prime to either read the eye gaze data and store yourself, synchronsing it with stimulus onset/offset yourself, or possibly you can send onset/offset events to the eye tracking PC.

[David McFarlane]

If you are asking just how to mechanically line up E-Prime data with
eye-tracker data after the fact during data processing (e.g., with
Excel), then I have nothing to add.

If you are asking how generate data during the session in order to
translate timestamps between E-Prime & eye-tracker ... I ran across
this very problem awhile ago when using E-Prime in conjunction with an
Arduino. I solved it the same way that I would solve it with people --
I look at my watch, ask my companion what time they have on their watch,
and write down both times. Thereafter I can translate times from one
watch into times for the other.

So with two electronic devices (e.g., E-Prime vs. eye-tracker or
Arduino), Device A records its own time, and immediately also gets the
time from Device B. If you want to compensate for communication delays,
Device A records its own time both just before and just after it gets a
timestamp from Device B, and then considers the Device B timestamp to be
equal to the average of Device A's before & after timestamps. It does
not matter whether Device A is E-Prime or the external device, and
vice-versa (in my case, E-Prime requested the time from the Arduino).
(This all assumes, of course, that the clocks on both devices keep
proper time except for a constant offset -- otherwise, you might do a
synchronization both at the start and at the end of the session, and
then do a linear interpolation for times in between.)

Most likely people who do serious timekeeping among multiple devices
have long ago solved this problem, and it would be interesting to learn
from them. But this is my hacked-out solution.

-- David McFarlane

[Nadia Rohl]

Thanks David for your simple and useful proposal!  

понедельник, 14 марта 2016 г., 20:34:12 UTC+1 пользователь McFarlane, David написал: