trials attribute

The trials attribute specifies the sequence of trials to be run in the block.

Member of

Syntax

/ trials = [trialnumber, trialnumber = trialname; trialnumber-trialnumber = selectmode(trialname, trialname,...); trialnumber, trialnumber-trialnumber = trialname]

/ trials = [trialnumber-trialnumber = list.name]

Parameters

trialnumber

A non-negative integer specifying the trial number.

trialname

The name of a trial defined elsewhere in the script to be run on this block.

list.name

The name of a trial defined elsewhere in the script to be run on this block.

selectmode

One of the following values:

Value	Description
noreplace	Randomly selects without replacement which trial in the group to run.
noreplacenorepeat	Randomly selects which trial in the group to present without replacement and without selecting any single trial consecutively.
replace	Randomly selects with replacement which trial in the group to run.
replacenorepeat	Randomly selects which trial in the group to present with replacement and without selecting any single trial consecutively.
sequence	Presents each trial in the group.

Remarks

The integers to the left of the equal signs represent ordinal positions within the sequence of trials. Trials can be directly assigned to a position in the sequence using the equals sign. A trial can be simultaneously assigned to multiple positions by separating the position numbers with commas (equivalent to "and") or dashes (equivalent to "through"). All trial positions in the block must be assigned to a trial or set of trials.

Examples

The first five trials of the following block are practicetrial, and the last five trials are testtrial:

<block myblock>
/ trials=[1-5=practicetrial; 6-10=testtrial]
</block>

The following block randomly selects either lefttrial or righttrial for each of its ten trials. Both trial types are run exactly five times.

<block myblock>
/ trials=[1-10=noreplace(lefttrial, righttrial)]
</block>

The following block selects trials one through ten from a list element named 'trialselector' containing a set of trial.

<block myblock>
/ trials=[1-10=list.trialselector]
</block>

The following block randomly selects either testtrial or distractortrial for each of its 12 trials. The testtrial is run exactly 8 time and distractortrial is run 4 times.

<block myblock>
/ trials=[1-12=noreplace(testtrial, testtrial, distractortrial)]
</block>

The following block runs bigtrial on even numbered trials and littletrial on odd numbered trials.

<block myblock>
/ trials=[1,3,5,7,9 = littletrial; 2,4,6,8,10 = bigtrial]
</block>