occasional skips

[Caren Frosch]

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
>>
>>