I wonder if the test was on the participants rather than the stuff on the plate.

How well do these folks find the note paper after ingestion? Do they overwrite their previous notes? How well can they tick the little boxes?

Does Spam taste better if you close your eyes?

with your blindfold?

Tastes like chicken

These people were testing vegetarian beef. Predecessor to Beyond Meat, called Not Quite Meat.

Here's what they're eating:
https://www.shorpy.com/node/15605

"Thanks to you all for assisting today. We'll be sampling and judging five chilis from local restaurants. The blindfolds will ensure a fair result.

Now, the five chilis will be from:
Nasty Ed's Chili House in Lanham,
Tommy's Tasty Tureen in Mount Pleasant,
Ben's Chili Bowl from U Street in DC,
Saucy Suzie's Saucy Soupies in Beltsville, and
Maurice's Sedate but Great Chili-Rama in Foggy Bottom.

Once you've cleaned your palates with the apple slices, we'll begin today's taste test!!!"

But, of course, Magritte was Belgian.

The French they are a funny race (or so saith Preston Sturges).

I'm guessing the apples are for palate cleansing?

I don't know that I could be persuaded to eat something if I had to be blindfolded first.

I assume that’s what the apples are for.

[I always knew JennyPennifer and I were on the same page.]

The person upper left is either doing an Oliver Twist impression or might be getting ready to lick the plate clean, I'm not sure which.

They're testing soyburgers 40 years before they were perfected.