Frustrating trial repeats

ldobb — Thu, 19 Nov 2015 14:30:02 GMT

Hi Dave,
I'm hoping you can help me again with this script that you've already contributed so much to!

I have attached the script. Here is the problem. I have exactly 62 trials of matched images. Each pair should be shown once with "<" and once with ">" and all of this totals to 62 trials. However, when I've been running the trial monkey, some of the pairs/arrows are repeated while others are skipped - it still totals to 62, but it's not getting every trial. I'm sure it's a simple fix but I've hit a wall.

Thanks so much in advance.
Warmly,
Lily

RE: Frustrating trial repeats

ldobb — Thu, 19 Nov 2015 14:30:02 GMT

I totally see where I went wrong. Thank you for the thorough explanation.

RE: Frustrating trial repeats

Dave — Thu, 19 Nov 2015 13:46:20 GMT

For example

<picture alcoholR>
/ items = ("1P_6.jpg","1P_7.jpg","1P_8.jpg","1P_9.jpg","1P_10.jpg", "1P_15.jpg", "1P_16.jpg", "1P_17.jpg", "1P_18.jpg")
/ select = noreplace
...
</picture>

<picture nonalcL>
/ items = ("2P_6.jpg","2P_7.jpg","2P_8.jpg","2P_9.jpg","2P_10.jpg", "2P_15.jpg", "2P_16.jpg", "2P_17.jpg", "2P_18.jpg")
/ select = picture.alcoholR.currentindex
...
</picture>

defines 9 pairs. However, *two* of your <trial> elements sample from those stimulus elements above:

With left arrow:
<trial alcoholBL>
...
/ stimulustimes = [0 = fixation; 500 = erasefixation, alcoholR, nonalcL, arrowL; 700 = blankscreen, drink_nonalc, drink_alc]
...
</trial>

With right arrow:
<trial alcoholBR>
...
/ stimulustimes = [0 = fixation; 500 = erasefixation, alcoholR, nonalcL, arrowR; 700 = blankscreen, drink_nonalc, drink_alc]
...
</trial>

Think of the two paired <picture> elements as a single deck of 9 cards labeled A to I. Think of <trial alcoholBL> as your left hand and <trial alcoholBR> as your right hand. Now start drawing cards from the deck (without replacement) randomly with your left and your right hand. Once there are no more cards left in the deck, reshuffle it and repeat once more.

Question: Is there any reason why you should have ended up with having drawn the cards {A,B,C,D,E,F,G,H,I} once with your left hand and the also cards {A,B,C,D,E,F,G,H,I} once with your right hand? No.

What you need to do is set up separate stimulus elements -- one set for each <trial> element to draw from. I.e. you need to do

<picture alcoholR_arrowL>
/ items = ("1P_6.jpg","1P_7.jpg","1P_8.jpg","1P_9.jpg","1P_10.jpg", "1P_15.jpg", "1P_16.jpg", "1P_17.jpg", "1P_18.jpg")
/ select = noreplace
...
</picture>

<picture nonalcL_arrowL>
/ items = ("2P_6.jpg","2P_7.jpg","2P_8.jpg","2P_9.jpg","2P_10.jpg", "2P_15.jpg", "2P_16.jpg", "2P_17.jpg", "2P_18.jpg")
/ select = picture.alcoholR_arrowL.currentindex
...
</picture>

for use in

<trial alcoholBL>
...
/ stimulustimes = [0 = fixation; 500 = erasefixation, alcoholR_arrowL, nonalcL_arrowL, arrowL; 700 = blankscreen, drink_nonalc, drink_alc]
...
</trial>

and

<picture alcoholR_arrowR>
/ items = ("1P_6.jpg","1P_7.jpg","1P_8.jpg","1P_9.jpg","1P_10.jpg", "1P_15.jpg", "1P_16.jpg", "1P_17.jpg", "1P_18.jpg")
/ select = noreplace
...
</picture>

<picture nonalcL_arrowR>
/ items = ("2P_6.jpg","2P_7.jpg","2P_8.jpg","2P_9.jpg","2P_10.jpg", "2P_15.jpg", "2P_16.jpg", "2P_17.jpg", "2P_18.jpg")
/ select = picture.alcoholR_arrowR.currentindex
...
</picture>

for use in

<trial alcoholBR>
...
/ stimulustimes = [0 = fixation; 500 = erasefixation, alcoholR_arrowR, nonalcL_arrowR, arrowR; 700 = blankscreen, drink_nonalc, drink_alc]
...
</trial>

In other words: You need *two* identical decks of 9 cards -- one to draw from with your left hand, one to draw from with your right hand.

Millisecond Forums » Millisecond Forums » Inquisit 4 » Frustrating trial repeats

Frustrating trial repeats

RE: Frustrating trial repeats

RE: Frustrating trial repeats