@evelyns_pet_zebra
I don’t approve of your unwarranted sarcasm.
The brain automatically associates a bigger package with bigger content, just as it equates a brand name with quality—as mentioned in this question
An example. Whenever I go through the supermarket and see a big package of cornflakes, the first impression i have in comparison with smaller packages nearby is “the bigger one must have more content.” I don’t have control over that, as it is automatic. But as a conscious buyer I then look on the actual weight.
But the point is: Most people are not conscious buyers, and they let themselves be fooled by the package size, and then buy the bigger package, even though it might have the same or even less content then the smaller package next to it.
The number one priority of any business is money. And if they can improve sales by exploiting basic psychology and simply increasing the package size without increasing content, then that is what they will do.