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!