Image remains visible at 1ms presentation time

[David McFarlane]

What JoAnn said.  Plus, thoroughly study the "Critical Timing" 
chapter in the User's Guide that came with E-Prime.  (Even better if 
you can study that chapter in the Guide that came with EP1 instead of 
the new EP2 edition.)

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

/----
Stock reminder:  1) I do not work for PST.  2) You may reach PST's 
trained staff (and other support facilities) at 
https://support.pstnet.com .  3) If you do get an answer from PST 
staff, please extend the courtesy of posting their reply back here 
for the sake of others.
\----


At 10/2/2014 11:19 AM Thursday, JoAnn Silkes wrote:
>So far as I understand it, it's not possible to get as fast as a 1 
>ms presentation rate due to the limitations of the refresh rate of 
>the computer monitor. With a 100 Hz refresh rate, the quickest 
>presentation that you can achieve is 10 ms; you would need a 1000 Hz 
>refresh rate for a 1 ms presentation, which I don't think exists. 
>I've also found that, depending on the computer I'm using, sometimes 
>asking EPrime to present something for just a single frame (i.e., 10 
>ms when the refresh rate is 100 Hz), the processor can't quite keep 
>up and it ends up dropping frames, so the minimum I can really do is 
>two frames (in this example, 20 ms). My guess is that you've got a 
>mismatch between refresh rate and requested exposure duration, and 
>that's throwing everything off.
>
>Another thing to think about is whether you're using masking, or 
>just relying on the rapid presentation rate. Perception of 
>extraordinarily brief presentations is still likely, especially for 
>images, if you don't have adequate masks present.
>
>Good luck figuring it out.
>
>JoAnn.
>
>
>On Wednesday, October 1, 2014 11:39:17 PM UTC-7, Tan Li wrote:
>Hi!
>
>I'm starting out with E-prime and using it for a psychology 
>experiment, where I'm employing a image prime. Even when I change 
>the duration of presentation of the image to 1 ms, I can still see 
>the image flash during the run rather than appearing "invisible". 
>Another study took <14 ms for the primes to appear invisible.
>
>On DataAid, there is no ActionDelay for the image. DurationError is 
>-1, and OnsetDelay ranges from 0-1 ms. Each image is about 240KB.
>
>Would anyone have any idea what's happening? I haven't been able to 
>find an answer in the database...
>
>Any reply is much appreciated!

-- 
You received this message because you are subscribed to the Google Groups "E-Prime" group.
To unsubscribe from this group and stop receiving emails from it, send an email to e-prime+unsubscribe at googlegroups.com.
To post to this group, send email to e-prime at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/e-prime/542d8b00.6437320a.7166.0814SMTPIN_ADDED_MISSING%40gmr-mx.google.com.
For more options, visit https://groups.google.com/d/optout.