Millisecond Forums

Increasing the number of trials in the dot probe paradigm

https://forums.millisecond.com/Topic20146.aspx

By alexa - 11/16/2016

Hello,

I have aquestion concerning the modification of the dot probe paradigm. I am currentlyusing the script of the alcohol DOT PROBE TASK - with images (Katja Borchert,last updated:  08-17-2015). I have donesome modifications – I replaced „alcohol“ with „highcaloric” and „neutral“ with“lowcaloric” because I would like to compare attentional bias to low- and highcaloricfood stimuli. Then, I have changed the name of the items accoding to the nameof my pictures.

I would nowlike to change the DP. Originally, the DP comprises 10 practice trials, 40alcohol/neutral (10*4) trials and 40 filler trials. I would like to keep the 10practice trials and 40 filler trials but do more comparisons betweenhigh/lowcaloric food (instead of 10: 20 pairs of pictures --> 80 trials). I have changed the scriptaccording to my needs and it runs. But when I controlled the rawdata, I haveseen that for example some pictures pairs are presented 3 times, whereas otherpictures pairs 5 times. So I am pretty sure I have done something wrongmodifying the script (1. listing more items (<itemhighcaloricTarget_images>); 2. changing the lists (<listhighcaloricTarget_itemnumbers> <list highcaloricTarget_positions><list highcaloricTargetprobe_congruence>) as well as 3. the parameter <blockImageDotProbeTask>.

Is thereanything more I have to do that the script works the way I want?

Thanks alot for your help!

Best,

Alex

 
By Dave - 11/16/2016

alexa - Thursday, November 17, 2016

Hello,

I have aquestion concerning the modification of the dot probe paradigm. I am currentlyusing the script of the alcohol DOT PROBE TASK - with images (Katja Borchert,last updated:  08-17-2015). I have donesome modifications – I replaced „alcohol“ with „highcaloric” and „neutral“ with“lowcaloric” because I would like to compare attentional bias to low- and highcaloricfood stimuli. Then, I have changed the name of the items accoding to the nameof my pictures.

I would nowlike to change the DP. Originally, the DP comprises 10 practice trials, 40alcohol/neutral (10*4) trials and 40 filler trials. I would like to keep the 10practice trials and 40 filler trials but do more comparisons betweenhigh/lowcaloric food (instead of 10: 20 pairs of pictures --> 80 trials). I have changed the scriptaccording to my needs and it runs. But when I controlled the rawdata, I haveseen that for example some pictures pairs are presented 3 times, whereas otherpictures pairs 5 times. So I am pretty sure I have done something wrongmodifying the script (1. listing more items (<itemhighcaloricTarget_images>); 2. changing the lists (<listhighcaloricTarget_itemnumbers> <list highcaloricTarget_positions><list highcaloricTargetprobe_congruence>) as well as 3. the parameter <blockImageDotProbeTask>.

Is thereanything more I have to do that the script works the way I want?

Thanks alot for your help!

Best,

Alex

 


<block ImageDotProbeTask>
/onblockbegin = [values.task = 2]
/trials = [1-120 = noreplace(highcaloric, Filler)]
</block>

Means you sample trials in equal proportions. You'll end up with 60 highcaloric trials and 60 filler trials in random order.

To achieve 80 highcaloric trials

> "40 filler trials but do more comparisons betweenhigh/lowcaloric food (instead of 10: 20 pairs of pictures --> 80 trials)"

you need to specify
/trials = [1-120 = noreplace(highcaloric, highcaloric, Filler)]
By alexa - 11/16/2016

Dave - Thursday, November 17, 2016
alexa - Thursday, November 17, 2016

Hello,

I have aquestion concerning the modification of the dot probe paradigm. I am currentlyusing the script of the alcohol DOT PROBE TASK - with images (Katja Borchert,last updated:  08-17-2015). I have donesome modifications – I replaced „alcohol“ with „highcaloric” and „neutral“ with“lowcaloric” because I would like to compare attentional bias to low- and highcaloricfood stimuli. Then, I have changed the name of the items accoding to the nameof my pictures.

I would nowlike to change the DP. Originally, the DP comprises 10 practice trials, 40alcohol/neutral (10*4) trials and 40 filler trials. I would like to keep the 10practice trials and 40 filler trials but do more comparisons betweenhigh/lowcaloric food (instead of 10: 20 pairs of pictures --> 80 trials). I have changed the scriptaccording to my needs and it runs. But when I controlled the rawdata, I haveseen that for example some pictures pairs are presented 3 times, whereas otherpictures pairs 5 times. So I am pretty sure I have done something wrongmodifying the script (1. listing more items (<itemhighcaloricTarget_images>); 2. changing the lists (<listhighcaloricTarget_itemnumbers> <list highcaloricTarget_positions><list highcaloricTargetprobe_congruence>) as well as 3. the parameter <blockImageDotProbeTask>.

Is thereanything more I have to do that the script works the way I want?

Thanks alot for your help!

Best,

Alex

 


<block ImageDotProbeTask>
/onblockbegin = [values.task = 2]
/trials = [1-120 = noreplace(highcaloric, Filler)]
</block>

Means you sample trials in equal proportions. You'll end up with 60 highcaloric trials and 60 filler trials in random order.

To achieve 80 highcaloric trials

> "40 filler trials but do more comparisons betweenhigh/lowcaloric food (instead of 10: 20 pairs of pictures --> 80 trials)"

you need to specify
/trials = [1-120 = noreplace(highcaloric, highcaloric, Filler)]
That works perfectly! Thanks a lot!!