occasional skips

[Leisha Wharfield]

I've done many experiments with infinite time & various allowable inputs 
with no such problem. I honestly agree with Doruk that there must be a 
timing issue somewhere.

Leisha

Caren Frosch wrote:

>
> hm, that's interesting. Did you figure out a way around that problem? 
> I suppose I could set the duration so it's long enough to ensure the 
> participants reads it.
> Caren
>
> philippe goldin wrote:
>
>> Uisng Epimre v2, we have also observed that on a slide set to 
>> infinite time with a button press to terminate that slide, the slide 
>> will sometimes automatically terminate (without a button press) and 
>> advance to the next slide. We have not been able to identify the 
>> source of this irrgular problem.
>>
>> philippe
>>
>>
>>
>> At 05:27 PM 8/10/2007 +0100, Caren Frosch wrote:
>>
>>> Leisha Wharfield wrote:
>>>
>>>> Stimulus duration = infinite, Time limit = same as duration, End 
>>>> action = terminate?
>>>
>>>
>>>
>>> yes.
>>>
>>> I have a feeling it could have something to do with the pre-release 
>>> on the slide that appears prior to the skipped slide. Doruk 
>>> mentioned something about it and when I read up about it some more I 
>>> realised that the fact that I have pre-release on a slide which is 
>>> terminated by response input could be a problem (though it didn't 
>>> specifically say that this could cause skipping). I've taken the 
>>> pre-release out and will have to see if it happens again. As the 
>>> skipping has never happened to me I need to wait for my next 
>>> participant on Tuesday.
>>>
>>> Thank you for your help.
>>> Caren
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>> Caren Frosch wrote:
>>>>
>>>>> I ran a few more participants today. For the first one everything 
>>>>> ran smoothly. For the second one, the slide that should be 
>>>>> presented at the end of the practice trial skipped. E-prime 
>>>>> recorded the following data for that trial:
>>>>> RT: 0
>>>>> RESP: (blank)
>>>>> OnsetTime: 0
>>>>>
>>>>> To me that looks like it just skipped, but I cannot work out why. 
>>>>> Any suggestions?
>>>>>
>>>>> Thanks,
>>>>> Caren
>>>>>
>>>>>
>>>>>
>>>>> Caren Frosch wrote:
>>>>>
>>>>>> Hi Leisha,
>>>>>> I hadn't been recording any data for those trials as they are 
>>>>>> only instructions trials, but I've switched it on now. For the 
>>>>>> last participant where it happened it recorded a RT of 0. The 
>>>>>> stimulus duration is 'infinite' and the allowable response for 
>>>>>> this slide is not an allowable response on the task trials.
>>>>>>
>>>>>> I'm testing a few more people today. I'll see if I can shed some 
>>>>>> more light on the issue.
>>>>>>
>>>>>> Thanks for your input!
>>>>>> Caren
>>>>>>
>>>>>>
>>>>>> Leisha Wharfield wrote:
>>>>>>
>>>>>>> "It's also not possible that participants are accidentally hitting
>>>>>>> the key that moves the slide on as I deliberately chose a key away
>>>>>>> from the keys they are using to respond to the trials (and I don't
>>>>>>> tell them which key it is)."
>>>>>>>
>>>>>>> Do the data bear this out? There are no entries for notaskproc; 
>>>>>>> it never launches? Have you tried, during testing, prematurely 
>>>>>>> hitting the key that moves the slide on to see what happens? In 
>>>>>>> my experience, if there is an unexpected way to proceed through 
>>>>>>> the experiment, subjects will find it (& that's probably a good 
>>>>>>> thing, because it leads to refinement).
>>>>>>>
>>>>>>> The key that moves the slide on should only be an allowable 
>>>>>>> response in notaskproc, therefore hitting it prematurely should 
>>>>>>> do nothing. Is this the case?
>>>>>>>
>>>>>>> Leisha Wharfield
>>>>>>> Decision Research
>>>>>>> Eugene, Oregon, USA
>>>>>>>
>>>>>>> Caren Frosch wrote:
>>>>>>>
>>>>>>>>
>>>>>>>> I'm running an experiment where I have divided a list into four 
>>>>>>>> blocks, that is, the list consists of 160 trials and after 40 
>>>>>>>> trials it leaves the list to run another procedure which 
>>>>>>>> consists of one slide where participants are told whether or 
>>>>>>>> not to generate random numbers during the next block (actually 
>>>>>>>> one of 3 procedures: 'taskproc' 'notaskproc', 'endproc'). It's 
>>>>>>>> all been running fine. But I have found that for some 
>>>>>>>> participants it occasionally skips this step and they therefore 
>>>>>>>> end up doing one big block (consisting of 80 trials). Has 
>>>>>>>> anyone experienced this kind of thing before and do you have 
>>>>>>>> any suggestions as to what it might be? Could it be a hardware 
>>>>>>>> problem (e.g. the keyboard)?
>>>>>>>>
>>>>>>>> Any suggestions would be much appreciated as I just can't 
>>>>>>>> figure out why it's doing it. When I run through the experiment 
>>>>>>>> myself it's always fine. It's also not possible that 
>>>>>>>> participants are accidentally hitting the key that moves the 
>>>>>>>> slide on as I deliberately chose a key away from the keys they 
>>>>>>>> are using to respond to the trials (and I don't tell them which 
>>>>>>>> key it is).
>>>>>>>>
>>>>>>>> Thank you,
>>>>>>>> Caren
>>>>>>>>
>>>>>
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>>>
>>> -- 
>>> Dr. Caren Frosch
>>> Research Fellow
>>> School of Psychology and Clinical Language Science
>>> University of Reading
>>> Earley Gate
>>> Reading
>>> RG6 6AL
>>>
>>> E-mail: c.frosch at rdg.ac.uk
>>> Phone: 0118 3785538
>>>
>>
>>
>> **************************************************************
>> Philippe Goldin, Ph.D.
>> Department of Psychology
>> Stanford University
>> Jordan Hall, Bldg. 420, Room 126
>> Stanford, CA 94305
>>
>> Tel: 650-723-5977
>> Fax: 650-725-5699
>> E-mail: pgoldin at stanford.edu
>> website: Clinically Applied Affective Neuroscience
>> http://www-psych.stanford.edu/~caan/
>>
>>
>>
>>
>>
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-- 
“And then many things happened at the same moment.”