Multiple Arrangement Task
With the Multiple Arrangement task, you can efficiently get similarity judgments among a large number of items in a multi-dimensional space. This is also known as Inverse MDS and "SPatial Arrangement Method" (SPaM).
- Instruction hint
- This will be displayed on the screen during the task. Max 80 characters
- Extended instruction
- Shown when the user hovers over the hint. Max 500 characters
- Item Size
- Height of the stimuli in % of the width of the field. Default 8%. Must be between 2% and 20%. The width is adapted according to the original aspect ratio of the image.
- Evidence utility exponent
- When determining which stimuli to select for the next trial, the evidence weight of each stimulus has this exponent applied to it, to calculate it's utility if it were picked. Default: 10
- Min required evidence weight
- Among all pairs of stimuli, if the pair with the lowest evidence has an evidence weight higher than this, the task is done. The participant will be presented with new trials until this is achieved, or the time limit Max session length runs out, whichever comes first. Default: 0.5
- Max session length (in minutes)
- Total amount of time that the participant may spend on the task before the experiment continues. Time in between trials, or time spent on trials that are not submitted (i.e. the subject closes the browser) does not count towards this time limit. Default: 60 minutes.
- Maximum number of objects presented in any one trial
- If you have selected more stimuli than this value, the first trial will consist of a random sample of this size from your stimuli. Default: 300 stimuli.
- The number of accepted ignored stimuli from multiarrange that have not been placed in circle. Default: 0 (All items must be placed)
- Stimuli start to the sides
- By default the stimuli start out surrounding the circle, this puts them to the right and left
Settings for Attention Checks
With these options you can enable attention check trials to be presented after each main MA trial. Keep attention_checks_per_trial at 0 to disable this.
- There are four different modes of attentions check:
- Whether to present two or three stimuli in a check trial. When presenting two, the distance is with respect to the maximal distance (the circle diameter). When presenting three, the distances of the pairs are relative to each other (which is more in line with the MA concept)
- There are four different ways to determine the number of checks per trial:
- Fixed number per trial: every trial will have the same number of checks
- Percentage of Stimuli: the number depends on the amount of stimuli in this MA trial
- Percentage of Pairs: the number depends on the amount of pairs in this MA trial (non-linear)
- See above for the unit
- Used to limit the number from attention_checks_per_trial.