That's me actually.

I can buy two gallons of milk at Costco for the price of one gallon at my local store. But I don't buy from Costco because the second gallon always goes bad and I throw it out. Throwing out food feels bad.

Anyway, what do I care about the "free" second gallon if I don't actually drink it?

Edit: hey look, a study:

> A series of experiments demonstrates that consumers exhibit aversion to waste during forward-looking purchase. These experiments further reveal that such behavior is driven by distaste for unused utility, a reaction that is shown to be distinct from an aversion to squandering money. Waste aversion is especially pronounced when consumers anticipate future consequences and deprivation is salient. In addition to demonstrating robustness across consumers and marketing contexts, the results also demonstrate how waste aversion can lead to self-defeating behavior in which consumers forego desired utility.

http://www.sciencedirect.com/science/article/pii/S1057740811...

Yep, I agree here. Sounds like to me the article is trying too hard to sound smart in its "research" and "economics", and consequently fails to make some simpler reasonings, such as perhaps they didn't want to waste food. Or in other words: 20pcs for 6.40 is the REAL pricing, they just offer a smaller portion (making them more profit) for the same amount of money, if you so desire.

I don't see how there is a contradiction between homo economicus and behavioral economics theories. If people derive disutility from wasting food, then it's perfectly rational to choose 10 nuggets over 20 if you only plan to eat 10 nuggets.

I thought that was part of classical homo economicus. If buying something would cause you some emotional disquiet (because you suspect you're wasting resources), then your willingness to pay for that product is lower, and you won't buy it. So it explains it pretty well. Also, the article mentioned this possibility (that 20 is simply too many) repeatedly.

They also mention (indirectly) that the nuggets themselves are pretty much free. So the cost to McDonalds is the same (largely) for 10 and 20 pieces: labour, energy, rent etc.

I don't think even McDonald's have such good quality control in place that if, say 10 nuggets costs 50 cents, and 20 a dollar, other factors than if people buy 10 or 20 totally dominates the profit.