Millisecond Forums

Shortening the WCST/data interpretation

https://forums.millisecond.com/Topic17981.aspx

By CAA - 12/15/2015

Greetings,
Due to time constraints, I will shorten the WCST to the same length as the simplified WCST.

The default of the Simple WCST is:

<value>
/cstotaltrials = 128
/cstotalblocks = 2
/correctstreakthreshold= 4
/picsize 30%
</values>

The default of the WCST is:
<values>
/cstotaltrials = 128
/cstotalblocks = 2
/correctstreakthreshold = 10
/setmaintainthreshold = 5
/picsize = 30%
</values>

My question is, what is the setmaintainthreshold, and what should I set it to? I will set the correctstreakthreshold to 4, similar to the simple WCST.
It is defined as: Number of consecutive correct responses after which an incorrect response is scored as a "Failure to maintain Set"

What does this variable do? I do not understand the definition.

Moreover, what is the difference between TotalError, PerseverativeError and FailureMaintainSet in the summary data?

Thanks in advance. Cheers.
CA
By Dave - 12/15/2015

> My question is, what is the setmaintainthreshold, ...

"Failure to maintain set" means the *loss of the correct sorting rule during performance*. Suppose you have identified the current sorting rule to be "color". You respond correctly according to that rule for, say, 5 trials and then -- suddenly -- respond incorrectly, i.e., you "lost" or "forgot" or "failed to maintain" the sorting rule.

/setmaintainthreshold = 5

defines the *threshold*. After 5 consecutive correct responses -- just like in the example I gave above -- a sudden incorrect response is scored as a failure to maintain set. Setting

/setmaintainthreshold = 3

would score a sudden incorrect response after *3* consecutive correct responses as a failure to maintain set.

> and what should I set it to?

That is up to you and what you deem appropriate.

> Moreover, what is the difference between TotalError, PerseverativeError and FailureMaintainSet in the summary data?

The variables are explained in the script's comments.

Totalerror represents all incorrect responses across the task.

totalerror:                                            sums up all the incorrect responses across the task

The others represent different types / categories of errors.

Sum_PerseverativeError:                                sums up all error trials with values.perseverativeresponse = 1

where perseverativeresponse is defined as

PerseverativeResponse:                                1 = response is still in compliance with the old rule after a rule switch (and
                                                                              no response has been made yet that violates the old rule)
                                                                              0 = any other response

Note: Not every perseverative response is a perseverative error. Hence the bolded part.

We have already covered failure to maintain set above, which is defined as

Sum_FailureMaintainSet                                   keeps a total of the number of times a participants selects an incorrect card after having
                                                                                maintained a correct streak of 5 or higher (default)