How to use shelf record

Online experiments
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1

Hello,

starting with version 2022.2.0 PsychoPy introduced the shelf record which allows " counterbalancing online: by tracking the number of participants that have been in each group". I couldn’t find any description of how to use this feature. How do I use it?

Best wishes Jens

2

Hi There,

The documentation is here clearly we need to better signpost it! at the moment it is listed under multisession testing and counterbalancing online here any suggestions for a more obvious location?!

Thanks!
Becca

1 Like
3

I think it would be helpful to link to the guides when you introduce the shelf in the changelog :slight_smile: Changelog — PsychoPy v2023.2.3

Also, is it possible that I could use the shelf for an issue I currently have where each observer only sees 25% of the images, but I cannot figure out how to load them specifically so they end up downloading 4 times the images, they need? I have more info about my issue here: Cannot use Static/Resource Manager Component to load images while observers read instructions - #2 by simon.dp

4

Hi Becca,

I am currently struggling to use the shelf in a very basic example. I created a dictionary record “counterbalancing” with the content

{
  "group": [
    1,
    2,
    3,
    4
  ],
  "counter": [
    0,
    0,
    0,
    0
  ]
}

In my experiment I have the lines

groups = await psychoJS.shelf.getDictionaryFieldValue({key: ["counterbalancing"], fieldName: "group"})
counters = await psychoJS.shelf.getDictionaryFieldValue({key: ["counterbalancing"], fieldName: "counter"})

console.log(groups)
console.log(counters)

and both logs are “null”.

Can you give me a hint about what my mistake is?

Thanks!
Adrian

Edit: Trying to test the demo also results in an error (existing_participants is null) even though I created the required empty dictionary record “session_tracker”.