blocks attribute

The blocks attribute specifies the sequence of blocks to run in the experiment.

Member of

Syntax

/ blocks = [blocknumber, blocknumber = blockname;blocknumber = list.name; blocknumber-blocknumber = selectmode(blockname, blockname,...); blocknumber, blocknumber-blocknumber = blockname]

Parameters

blocknumber

A non-negative integer specifying the block number.

list.name

The name of a list element containing a set of blocks.

blockname

The name of a block 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 block in the group to run.
noreplacenorepeat	Randomly selects which block in the group to present without replacement and without selecting any single block consecutively.
replace	Randomly selects with replacement which block in the group to run.
replacenorepeat	Randomly selects which block in the group to present with replacement and without selecting any single block consecutively.
sequence	Runs each block in the group.

Remarks

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

Examples

This example runs five blocks selected from a list element called 'blockselector':

<expt example>
/ blocks=[1-5=blockselector]
</expt>

The first five blocks of the following block are practiceblock, and the last five blocks are testblock:

<expt>
/ blocks=[1-5=practiceblock; 6-10=testblock]
</expt>

The following expt randomly selects either leftblock or rightblock for each of its ten blocks. Both block types are run exactly five times.

<expt>
/ blocks=[1-10=noreplace(leftblock, rightblock]
</expt>

The following expt randomly selects either testblock or distractorblock for each of its 12 blocks. The testblock is run exactly 8 time and distractorblock is run 4 times.

<expt>
/ blocks=[1-12=noreplace(testblock, testblock, distractorblock)]
</expt>

The following expt runs bigblock on even numbered blocks and littleblock on odd numbered blocks.

<expt>
/ blocks=[1,3,5,7,9 = littleblock; 2,4,6,8,10 = bigblock]
</expt>