A recent study out of Harvard and published by the American Association of Wine Economists gave 18 volunteers a blind taste test of duck liver pate, pork liver pate, spam, liverwurst, and dog food. The volunteers were asked to rate the taste and to guess which one was dog food.
The dog food was rated the lowest. I guess we should expect much less attention to flavor would be put into a product for an eater who doesn't have much choice in the selection and can't articulate their displeasure (at least not by posting a bad review on Yelp).
The volunteers were not good at all at guessing which one was the dog food. Almost half thought the liverwurst was dog food. Only three out of the eighteen correctly guessed which one it was.
Here is what I found interesting though. If you compare the ratings and the dog food guesses, many of the volunteers guessed that their second or third favorite was the dog food. Only three of them guessed that their least favorite was the dog food. What this means is that we expect dog food to taste reasonably good, at least compared to spam, liverwurst, and pate.