counter element

The counter element defines a sequential or randomly selected set of values used to vary experimental conditions.

Attributes

<counter name>
/ allowRepeats = boolean
/ items = (value, value, value,... )
/ not = (stimulusname, stimulusname, stimulusname)
/ not = (countername, countername, countername)
/ select = selectmode(stimulus)
/ select = selectmode(list)
/ select = selectmode(integer, integer, integer, ...)
/ select = list
/ select = selectmode
/ select = index
/ selectionRate = rate
/ resetInterval = integer
</counter>

Properties

counter.name.currentItem
counter.name.currentItemNumber
counter.name.itemCount
counter.name.selectedCount
counter.name.selectedIndex
counter.name.selectedValue
counter.name.selectionMode
counter.name.selectionRate
counter.name.unselectedCount
counter.name.resetInterval
counter.name.name
counter.name.typeName

Functions

None.

Remarks

The counter element can be used to determine which stimulus items are selected from trial to trial, providing more control over item selection than is given by the stimulus element itself. Counters can also be used to specify the values from trial to trial of variable attributes (for example, the horizontal and vertical screen position of stimuli).

Examples

The following counter returns a sequence of numbers counting backwards from 5.

<counter backwards>
/ select = sequence(5, 4, 3, 2, 1)
</counter>

The following counter randomly selects values from 1 to 200 without replacement. All items are replaced after 10 blocks or after all of them have been selected.

<counter mycounter>
/ select = noreplace(1-200)
/ resetInterval = 10
</counter>