Milk tea & Tea milk

I heard of an interesting experiment once. I call this experiment "the Milk tea & Tea milk". First, we should know what is "Tea milk". Tea milk is the milk tea which is made by pouring tea in a cup of milk rather than pouring milk in a cup of tea. In this experiment, experiment designer should make some cups of milk tea and tea milk. Then find some subjects to taste each cup of milk tea and ask them to distinguish which one is milk tea and which one is tea milk. Normally, no one can distinguish the difference between each cup of milk tea. Therefore, the most interesting part is not finding some one who can tell the differences between mike tea and tea milk but figuring out a way to confirm that if the subjects can tell the differences or not.

To confirm whether the subjects can tell the differences, the order of cups has to be well arranged because the biggest factor, which influences the result of the experiment, is the subjects' state of mind. When a subject can't tell the differences, he or she may guess the answer. Normally, there's a pattern when we guess the answer- we hardly repeat our guesses. For example, if a subject's last answer was "tea milk", he will probably guess "milk tea " as the next answer.(here we call it pattern 1) However, the subject may repeats his or her guessed for one time sometimes; the pattern of  guesses may be two "tea milk" in a row followed by two "milk tea" in a row.(here we call it pattern 2)  Therefore, the order of cups shouldn't follow these patterns or those subjects may be able to make all the answers correct just by luck.
If I want to design this experiment. I will make four cups of milk tea and four cups of tea milk. Then give my subject four cups of tea milk first and asked he or she to give his or her answer after tasting each cup of tea. Next, I will give my subject four cups of milk tea and ask she or him for answers after tasting each cup of tea. Not to influence my subjects next answer, I tell them the answer at the end of the test. If my subjects can't tell the differences and guess with  pattern 1 or pattern 2, they will only have 50% correctness. (see the comparison below)
              My arrangement               XXXXYYYY          (X is tea milk, Y is milk tea)
(Pattern 1) Answers of my subject     YXYXYXYX    (50% correctness)
           
 My arrangement                               XXXXYYYY
(Pattern 2)  Answers of my subject   XXYYXXYY  (50% correctness)
         
As you can see, the correctness will not be over 50% if subjects guess their answer in pattern 1 and 2.
However, if the subjects guess three same answers in a row , repeating the pattern , the correctness may be up to 62.5%. (the possibility of this case is low because people normally don't repeat the same guesses three times). Therefore, only the subject whose correctness is over 70% can be refereed to the one who can distinguish tea milk and milk tea. In my opinion, the result of this experiment will be convincing because it is hard for subjects to achieve 70% correctness only by guessing. We can safely say that the subject whose correctness is under 70% can't tell the differences between milk tea and tea milk.

In addition to the psychological factors of subjects, one thing should be noticed. The proportion of milk and tea should be the same in every cup or the answers of subjects will be influenced. If you decide to make milk tea with 50% milk and 50%, every cups of milk tea or tea milk should be made in this proportion. The only control factor is the sequence of pouring milk and tea. If you are interesting in this experiment, you can invite some friends and design this experiment in your own way. You will have fun and discover something interesting in the experiment.