Practice version of MST

[Daniel Callow]

Hello,

I plan to have older adults perform the MST before and after an experimental condition on two separate days. This would require 4 versions of the MST that we plan to administer in a counterbalanced fashion. 

I know you have shown in your previous work that there doesn't seem to be a practice effect when performing the task multiple times. However, I presume that there is a higher chance that the first time the subject performs the task they may not fully understand it or are not as familiar with it as they would be on the other 3 attempts. 

My advisor and I have discussed allowing participants to perform a brief version of one of the MST task sets (say set 5) on the baseline day (before the two experimental days) to make sure the participants are comfortable with the task before performing it on days 2 and 3. Do you have any reasons for not doing this based on previous experience? 

Finally, which version of MST would consist of the shortest test time? I assume the # per condition 20 settings?

Thank you for any guidance you can provide!

Best,

Daniel Callow

[Shauna Stark]

Giving people a practice is a great idea. I don't see any concerns with having them do so as long as you use a different set of images each time. I recommend using sets 1-6.

Yes, the number of items per condition will alter how long the task takes to administer. While we found reliable results with as few as 20 items per condition, I personally feel more comfortable with 32 items (as opposed to the "standard" 64 items), but you will not have enough trials to look at 5 separate lure bins. You could still probably split them into low and high similarity lures though.

Hope this helps and good luck with your study!

Shauna