That next to last statement you make; where you state what variations both statistically and environmentally must be taken into account in all DBT's is the difficult part for me. The possible variants multiplied by infinite sets of conditions revolving around perceptuall and cognitive modulations by the subjects; wheew, it's exhausting just to think of it. So how do they accomplish this Sisyphean task? Allow me not to appear patronising. There are so many possible variables just in the existing neural conscripts of each individual unique at the time of the test it just seems impossible. And I believe you create a musical artifact internally whenever you listen. That takes in the surroundings and mood et all. Who hasn't heard a song that seemed blase' initially only to become a favorite over time. That is the best and simplest analogy I can come up with. But like I say; nobody implies Caruso can't sing; or Renoir can't paint. So we know instinctively what is good. That I think is why you build your system over time and experience. Those requisites must be accepted and that waters down any effect of DBT's.