I modified the letter memory task so that the items are words rather than letters. However, I realized that a way to cheat the task would be to simply select as many words as possible in the recall portion. I want the participants to only be able to select 3 words in the recall portion of each trial. The original letter memory task we modified did not have this problem. 

This is the file below.

> However, I realized that a way to cheat the task would be to simply select as many words as possible in the recall portion.

No, this is not a way to cheat the task. Your script (based on https://www.millisecond.com/forums/FindPost25959.aspx as far as I can see) only takes the *first three words* selected into account, which is the exact same way the original letter-based task behaves: It only takes the first three letters selected into account, any additional ones are ignored.

If you only want to *display* the first three words selected during the recall-trial, you can define the <text> element(s) responsible for that like so:

<text recalledwords>
/ items = ("<%list.recalledWords.item(1)%> <%list.recalledWords.item(2)%> <%list.recalledWords.item(3)%>")
/ position = (50%, 83%)
/ txcolor = red
/ erase = false
/ fontstyle = ("Arial", 5%, true, false, false, false, 5, 1)
</text>