WebExp2 Experimenter's Manual - School of Informatics - University ...

Defining your own behaviour for the stage If you want to get a different combination of behaviours, you
can specify the behavioural properties individually instead of specifying a type. Any options you want to use
should just be included as an empty tag — the options are listed in figure 9.
Note that if you include any of these tags in addition to a tag, they will override any settings from the
type. If no tag is included, then the three options are set to false and overridden by whichever options
you include.
Collecting Subject details The stage type subject is provided for you to collect information which is not
directly related to the experiment. The usual application of this will be to provide a stage near the beginning
of the experiment in which you request details about the participant (subject) of the experiment. This will
resemble a questionnaire. Details are recorded with the results.
5.5.4 Templates
An important concept in defining your stages is that of a template. There are two ways of constructing the
sequence of slides in a stage:
1. explicitly describe each slide
2. describe one or more template slides along with a repetitions parameter
If you use the first option, you can just write a sequence of slides which are shown in the order you describe
them (unless you specify an ordering or randomisation). You can also use the variables feature of slides.
Using the second option is very easy – you write your slides in the same way, but this sequence is used as a
template, and is duplicated a number of times. The sequence numbers for slides are automatically generated.
Repetitions For a stage where the same slide (or sequence of slides) is shown repeatedly with different
contents, the stage needs only contain one slide (or a sequence), along with a tag such as
5. The changeable components within a slide should also have an tag
which identifies a particular resource set from which resources will be imported. The sequence of one or more
slides will be repeated the specified number of times, with resources being imported each time from the resource
set specified in the import tag.
Note: It is up to you to ensure that your resource sets contain enough resources to fulfil all the imports in your
repeated template. If there are too few, nothing will be imported. Additionally, if you define one of the following
stage reorderings, they will be applied to the sequence of slides which are generated from your templates and
resource imports. In some cases this may have no practical application – usually you will want to randomise
either your imported resource sets, or the slides in your stage.
5.5.5 Hard stage orderings
The first way to specify a reordering of the slides in the experiment description file is to specify an tag
in the stage. This ordering, if valid, will be used for this stage unless overridden by a proper randomisation.
An ordering is specified as a comma-separated list of integers; for a stage with n slides, this should be a list of
the numbers 1 to n. However you can also leave numbers out, to provide a subsequence of the stage’s slides.
Thus an ordering for a 7-slide stage could look like this: 5,6,2,1, 3, 7. Note that you can
use whitespace in the list if it makes it more readable.
Note: If you have generated a stage from a template, you will have to take this into consideration if you decide
to define a hard ordering.
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