Psedorandomization with user-defined attributes

[mkrishnaswamy]

I am building an experiment with stimuli set with definitions that look like this:

Code:

"stimuli": {

  "den1": {
{
  "type": "audio",
  "content": "den_1.mp3",
  "visible": false,
  "stop": "den"
},
"ret1": {
{
  "type": "audio",
  "content": "ret_1.mp3",
  "visible": false,
  "stop": "ret"
},

"alv1": {
{
  "type": "audio",
  "content": "den_1.mp3",
  "visible": false,
  "stop": "alv"
}}

Here, an attribute "stop" is set with 3 possibilities. I am trying to pseudorandomize my trials so that stimuli with the same 'stop' attribute aren't places next to each other. I used:

Code:

{...
    "response_pairing" : "alternate",
    "delay" : 1,
    "stimulus_pattern": {"order": "pseudorandom", "attribute": "stop", "max_N": 1}
                        }

I got the following error message:

Code:

In the definition of "Testing1", the "pseudorandom" order with at most 1 consecutive target stimuli is impossible because there are too many stimuli with the target attribute "stop".

I want to know if this usage is correct, and if users are allowed to set more that 2 options for attributes?

Thanks in advance!

[Ting]

Hi, my guess is the issue is not the number of unique values for "stop", but rather the number of stimuli with the same "stop" attribute(s) defined in that trial template. Because you are asking FindingFive to present stimuli that repeat the "stop" attribute *at most* once in a row (the max_N setting), it's not possible to find a sequence that satisfies this constraint given your setup.

Does that seem true to you?

[mkrishnaswamy]

Hi, my guess is the issue is not the number of unique values for "stop", but rather the number of stimuli with the same "stop" attribute(s) defined in that trial template. Because you are asking FindingFive to present stimuli that repeat the "stop" attribute *at most* once in a row (the max_N setting), it's not possible to find a sequence that satisfies this constraint given your setup.

Does that seem true to you?

Thanks for your response! In my experiment, each trial has 36 stimuli, 12 with each kind of stop.  I want to make sure these 36 stimuli don't allow repetition of stimuli the same attribute more than once in a row. Do you think that would satisfy the condition for max_N?

[Ting]

Ah thanks for the explanation. And my apologies - my guess turned out to be wrong. At the time being, the pseudorandom method only looks at whether an attribute exists, but not its value. I don't think that's the optimal behavior, as evidenced by your totally reasonable case.

We can spend a little time this week tweaking this feature so that it recognizes the actual values of the attribute and performs pseudorandomization on them. Would it be possible for you to check back in on this thread in a week or so? We'll post an update when the study grammar devs implement this feature.

Thanks

[mkrishnaswamy]

That makes a lot of sense! I will do so. I'm glad I interpreted the grammar correctly, haha.

[Ting]

Hi - this should be possible now given the recent grammar update: https://discuss.findingfive.com/showthread.php?tid=146

Give it another try?

[mkrishnaswamy]

Hi - this should be possible now given the recent grammar update: https://discuss.findingfive.com/showthread.php?tid=146

Give it another try?

Thanks for this!