Hello.
I am going to create picture SPAN task as described by Engle et al (2016) [http://englelab.gatech.edu/2016/Hicks_Foster_Engle_2016.pdf] to use in my research.
I am using OSPAN task from Milisecond test library as a template.
In a nutshell in picture SPAN participants must remember sequence of pictures when solving math task, then subjects are required to recall picture in order of presentation.
In each trial of a phase of recalling pictures participants can do four actions:
recall one picture by clinking on it
clear all recalled picture (to start recalling from beginning in next trial)
provide empty frame (if he/she does not remember what picture should be on given position)
exit recall phase
Feedback in a form of sequence of recalled picture appears on the bottom of the screen.
I have some strange problem with action of proving empty frame in recall phase.
To handle feedback in recalled phase I have created nine pictures elements with values in item attribute, at the beginning of the script all this values are set to blank_b.jpg file containing only white rectangle and thus any of pictures is visible , then as participants click on subsequent pictures values are updated by names of choose picture to present image of this picture on a screen as a feedback.
e.g
<picture recalled_pictures_1>
/ items = ("<%values.recalled_picture_1%>")
/ size = (8%,8%)
/ position = (10%, 80%)
/ erase = false
</picture>
When participant click on picture in first trial of recalled phase values.recalled_picture_1 is update to name of image for choose picture e.g frog.jpg if participant click on frog picture and this resulting in presenting of frog picture on a bottom of a screen
When participant click not on picture but on a button "PUSTE" (EMPTY) in recalled phase the values.recalled_picture_1 should be update to blank.jpg resulting in black frame in feedback sequence on bottom of a screen.
And here my problem starts, I cannot update my values to a blank.jpg to present empty frame in feedback sequnecne, but I can update this values to other pictures file names.
e.g
This line of code intend to update values.recalled_picture_1 to blank.jpg, when participant click button PUSTE (PUSTE is a text element named X) :
if (values.picture_no == 1 && trial.recall_letter.response == "X") values.recalled_picture_1 = "blank.jpg";
but this does not work, when I click on button PUSTE script stops working and I have this message:
Unable to initialize <picture recalled_pictures_1> item number 1. Verify the item exists and is correctly defined.However when I change updates from blank.jpg to other file name e.g frog.jpg this works:
if (values.picture_no == 1 && trial.recall_letter.response == "X") values.recalled_picture_1 = "frog.jpg";
In such a case every time when I press button PUSTE I have frog picture presented in feedback sequence, this proved some clues that logic seems to be correct but sth wrong is with blank.jpg picture.
This is handled by <trial recall_letter>
I do not know why this code works for one file name but not for another, would anyone help me with this issue?
Than you in advance for any help.
Pleas find attached my script and files.