Friday, February 26, 2016

The Double Blind Test





Subtitle:  Do try this at home

Whilst this principled Scientific experiment uses Chocolate as the test substance, other materials are available :-)


Still Eating Chocolate?
Although technically off the list of consumables due to a healthier living lifestyle for 2016 race preparation, Marcus has made an exception in the name of Science.  Seems fair, right?


The Costs of this Experiment
At our local Swiss supermarket, the Lindt 100 gram milk chocolate bar is 2.60 CHF and the Coop house 100gram bar was 0.5 CHF

Experiment Goal
To see if Marcus can detect and prefer the top shelf expensive Lindt Milk chocolate over the very cheapest Supermarket brand.


What is a Double Blind Test
This means that neither the subject of the experiment Marcus, nor his skilled experimenter Agata know which chocolate bar is which (during the test).

To do this though, Marcus has to be literally blindfolded in the test. Had there been 3 people, this would not have been necessary.

In this Test
Marcus is doing the eating
Agata is doing the feeding to him and noting down his reactions and test data


Are you sitting Comfortably?

Good then we shall begin


With Agata well out of the way Marcus opened both bars of Chocolate



 Now both milk chocolate bars are slightly different in colour, the chunk sizes are slightly different, and on one side is a recognisable logo.

For this reason Marcus is going to be blindfolded during the test so he can only use his taste buds to tell the difference.



Marcus prepares two sets of samples.  The Coop house chocolate is on the left, marked 1, and the expensive Lindt is on the right marked 2.

[Postscript: in order to ensure that the taster cannot distinguish brands based on size, an extra step would be to cut the chocolate squares into randomly shaped sizes. ]







Marcus gets ready and asks Agata to come in.  She does not know which chocolate is which   (the logos are face down) and she is asked to choose a random order to feed me chocolate squares and write down my comments.


 I know,  I'm making this look too easy



Hopefully I am holding up the results, not some idiotic message, I can't see anything yet



Okay, now I get the wrappers out and I had numbered on the other side the 1 and the 2 so there is no dispute


There are the highlights of what I said, transcribed below.


Agata's Randomly selected order and Marcus Comment

(Square.Sequence)

D.1  Tastes Good
E.2  I think this is the same chocolate as 1
C.3  This is slightly less sweet, so first 2 must be Lindt, this one is Coop
B.4  This is the same as first 2, ie creamier, it's the Lindt
D.5  I like this the best so far, this one. Not sure which brand it is though!  Surely the Lindt?
E.6 This is creamier, than the last.  Must be Lindt.  Wait, this means 4 Lindt, so I must have got one wrong.  Oh No!


Conclusions

- Marcus did not correctly identify the 2 different Chocolate varieties all of the time

- He then chose, the Coop house chocolate as his favourite (D.5) and also simultaneously mistook it for Lindt!

- From a taste and even packaging point of view there is really very little in it

So for Marcus' staple milk chocolate it looks like he could be more economically served by the Coop, store branded chocolate.

And that dear friends is a Double Blind taste test.



#DoubleBlind
#DoubleBlindTest