The Symmetry span task is a complex span partner to the matrix span task. The participant is shown a series of grid locations one-by-one form the 4x4 grid in the center of the screen. The participant must remember the grids and the order in which they appeared. Afer each grid is shown the participant is shown an 8x8 grid that has a number of grids filled black to form a pattern. The pattern will either be symmetrical along the vertical axis or it will not and the participant must make this judgement using the left/right arrow keys before the next grid will be shown.
Task Details
Screenshots
Presentation Phase
Recall Phase
The XML
number of trials
randomised trials
matrix size
symmetry matrix dimensions/size
symmetry pattern fill range
You can download the default XML here. In this section I will point out the customisation options at your disposal by modifying values in the XML.
Under task settings there is a section of code where we tell the application where to find the executable that handles the digit span task. The property name/value keys here are where we can set task-specific properties.
Storage Phase
This set of customisable properties relate to the storage component of the task, therefore they are the same as described for the simple span counterpart (matrix span. These properties are found in the bean with id "symm_span".
Number of trials
You can select how many trials of each span size you want. The properties to edit here are:
- 'spanTwoTrials'
- 'spanThreeTrials'
- 'spanFourTrials'
- 'spanFiveTrials'
- 'spanSixTrials'
- 'spanSevenTrials'
- 'spanEightTrials'
- 'spanNineTrials'
Sequential/Randomised trial order
This property decides if the trials are administered in sequential order or not with regards to the list lengths. If sequential then all list length 2 trials are given, followed by all list length 3 trials, and so forth. However, it is often the case that a researcher may wish to administer these trials in a random order so that the participant is not aware on any given trial how many digits they will have to store/recall. The property to edit is:
- 'randomisedTrials'
Matrix Size
It is possible to select how many grids you would like in the matrix. The property responsible is:
- gridDimension
In addition there is an option to control the actual size (on screen) of the matrix.
- ScalingFactor
Processing Phase
This set of customisable properties relate to the processing component of the task where the participants are shown a grid with a pattern filled and must make a judgement on whether it is symmetrical. These properties are found in the bean with id "symm_processing".
Symmetry grid size
What do you want the dimensions of the matrix to be that delivers the pattern? The default value is "8" which produces an 8x8 grid with a pattern filled.
- GridDimension
- ScalingFactor
Pattern fill range
You can also control how many squares are used to make the patterns in the symmetry grid.
- MinSquares
- MaxSquares
Data Analysis
After running the symmetry span processing script (download from here) you will get a data frame with the following variables. Information on running the script and obtaining the processed data is here
Variable Name | Description |
---|---|
fta.score | This is the score the participant achieved when the full-trial accuracy scoring method is used. |
prop.score | The score obtained by the participant when the proportion correct method of scoring is used. |
number.successes | The score obtained by the participant when the number of correctly recalled elements method of scoring is used. |
processing.accuracy | The proportion of the symmetry judgements that were successfully answered. |
processing.median.rt | The median response time for answering during the processing phase. |
max.span | Maximum list length at which the participant successfully recalled all the elements in the trial. |
span.2.corr | Number of trials successfully answered (all grids recalled) at list length 2 - "NA" value if there were no trials at this list length administered |
span.3.corr | Number of trials successfully answered (all grids recalled) at list length 3 - "NA" value if there were no trials at this list length administered |
span.4.corr | Number of trials successfully answered (all grids recalled) at list length 4 - "NA" value if there were no trials at this list length administered |
span.5.corr | Number of trials successfully answered (all grids recalled) at list length 5 - "NA" value if there were no trials at this list length administered |
span.6.corr | Number of trials successfully answered (all grids recalled) at list length 6 - "NA" value if there were no trials at this list length administered |
span.7.corr | Number of trials successfully answered (all grids recalled) at list length 7 - "NA" value if there were no trials at this list length administered |
span.8. corr | Number of trials successfully answered (all grids recalled) at list length 8 - "NA" value if there were no trials at this list length administered |
span.9.corr | Number of trials successfully answered (all grids recalled) at list length 9 - "NA" value if there were no trials at this list length administered |
user | The value of the username of the account which produced the data |