[solved] Creating time stamps in eye tracking experiment

RubinCS

Dear Sebastian,

We are building a very simple experiment in opensesame (since this is the first time we are working with it), and we are using the Eye Link 2.
Basically, each trial looks like this:

(1) fixation (5sec)
(2) stimulus (i.e, a simple word) (5sec)

In total, we have three trials.

What we need to know is the following: We would like to send a message which is eventually printed in the final asc. file to see only the data about the eye behavior (i.e., pupil dilation, blinks, and fixation) only for the stimulus part (so not for the fixation part). Thus, we are only interested in the data for the eye behavior when the stimulus is presented.
For now, we only get the message when the trial starts and ends (but we cannot distinguish the fixation part from the stimulus part) (see also the example of our output).

Hope our question/problem is clear!

Thanks in advance.

Best,
Rubin and Jean

Link to example of our data: http://img.cogsci.nl/?q=57235aca23dfe

Josh

Hi Rubin and Jean,

The easiest solution will be for you guys to place the recording item in between the fixation and stimulus sketchpads. Of course the drift correction item will have to stay at the beginning of your trial sequence.

Does this help?

Cheers

Josh

eduard

Hi Rubin and Jean,

If you are not interested in the fixation part, why recording it in first place?
So, if you move the start_recording item before the stimulus, the start recording message will be aligned with the stimulus onset.

Alternatively, you can send a log message from within an inline_script (preferably run_phase):

exp.pygaze_eyetracker.log("Begin stimulus phase")

Hope this helped.

Eduard

RubinCS

Dear Josh and Eduard,

Jean thought that we couldn't use the start_recording more than once, or place it somewhere else in the trial. But thank you for your prompt response!

Best,
Rubin and Jean