This is a small boilerplate experiment for Self Paced Reading (SPR) with a moving window. Participants read sentences formatted in lines. Single words or groups of words are revealed when participants press a key (space-bar). An occasional question is asked to see whether they comprehend the text they have been reading.
Please read the generic documentation for some context.
The file globals.js contains a variable:
const ACCESS_KEY = '00000000-0000-0000-0000-000000000000';For uploading to the ILS data server you will need to change
this to the access_key that you obtained when your experiment
was approved. Your personal access key should look identical, but
with all the '0' changed. For elaborate info see globals.js.
The file stimuli.js contains a number of variables you can tweak
in order to adapt the stimuli the participants sees. There
are by default 2 lists. Each list gets its own
set of stimuli assigned. These lists can be used to implement
a Latin square design. The boilerplate has sentences in an
active, passive and filler condition. The two lists complement
each other, so an active stimulus in the first list is complemented
with a passive stimulus in the second list. Participants get one of these
lists assigned randomly. You can add additional lists if your experiment
requires this. For instance, to implement a Latin square design for four
conditions, you'd need to create four lists.
By defaut, the boilerplate experiment treats every word in the stimuli as a
group of its own containing one word. Note, in some papers, the terminology for
a group is a segment. Sometimes it is handy to group multiple words together,
to shorten the time it takes to complete the experiment for example. This is
possible, but must be enabled. The file globals.js contains another variable:
const GROUPING_STRING = null;To enable grouping you must define a useful delimiter between groups. A little bit further in the file there's a commented version of this:
const GROUPING_STRING = "/";So in order to enable grouping, comment the first version and uncomment
the latter. In theory you can fill out any string instead of the "/"
(useful in case you need to use / in a stimulus).
Notice the string is turned into a regular expression in order to split
the stimulus into parts and to remove the / in the case described here.
re = RegExp(GROUPING_STRING,'gu');So make sure if you are going to be creative, that the expression is valid.
In the stimulus file you should take care that the grouping string is removed from the stimulus. So you should take in mind how the stimulus would appear after the grouping string is removed.
{
stimulus : "This is/my fantasic stimlus./Don't you think!"
}The "/" will be removed, essentially gluing "is" and "my" together, just like "stimulus." and "Word".
{
stimulus : "This is/ my fantasic stimlus./ Don't you think"
}For some general information about understanding the output of jsPsych you
can visit the README.md of our jspsych output github page. This
boilerplate creates its own plugin in order to make an SPR stimulus. Currently this
stimulus is not listed in jspsych plugin list, because it is not part of
the official jsPsych source. So here we describe which output is specific for
the SPR.
The boilerplate has support for 15 groups of words. Remember that a group can
consist of a single word. Groups starting with a # in the stimulus list are
added to the output. Each reaction time is in ms. If less than 15 groups are
marked with a #, the remaining reactiontimes are set to -1 as an indication
that no response has been given for that word; this marks it as
invalid. The variables are listed as rt1, rt2 .. rt15 in the output.
The fixation cross that lures the eyes of the participant to the start of the
sentence is also implemented using the same spr-moving-window plugin, with the
single group/word '+'. All RTs for this trial will be set to -1.
In addition to the RTs three variables are added to the output:
- id
- item_type
- uil_save
The id (which you assign in stimulus.js) of the stimulus identifies 1
specific stimulus from your list. It is typically 1 to n, where n is the number
of items in your list. (Note that an item will appear in several conditions,
or item types. For instance in the template, the item with id 1 appears in the passive
condition in list 1, and in the passive condition in list 2).
The item_type is added to the output, also defined by you in stimuli.js.
In contrast the item_type of the fixation cross is always FIX_CROSS.
uil_save is added to the output variables to indicate whether this json opbject or one line in the output of the csv is worth saving, in other words is really mandatory for the analysis of your experiment. If it is defined for a trial it is either true or false - a boolean. You can use this boolean to filter your data. You can first check whether the uil_save is set and if it is set, you can examine whether it is true and if not, just throw the row-in-the-csv or JSON object away.
The question stimulus is a 'html-button-response' type of stimulus. From the information of jspsych output you should be able to figure out what jsPsych adds for each trial. In addition to what jsPsych adds, we add the following output variables:
- id (similar to the id in the section of the SPR stimulus above)
- item_type (similar to the id in the section of the SPR stimulus above)
- expected_answer: the answer that would be correct.
- uil_save (similar to the id in the section of the SPR stimulus above)
- answer the answer that the participant gave; one of [false, true].
- correct whether the given answer was the correct answer; one of [false, true].
- integer_correct whether the given answer was the correct answer; one of [0, 1].