Objects and materials: What compels us to throw away?

The other day, Steve and I went to see Professor Michael Griffin, the NASA Administrator under President Bush from 2005 to 2009, give a talk about complex systems on North Campus. Although he is has made some quite naive statements about climate change as you probably know, the talk was nonetheless fascinating and story-like. I can write about his talk, which focused on the interfaces between engineering disciplines, at a later time. But I want to write a bit about something that stuck me particularly strongly during the whole experience.

Generally, when someone as important as him gives a talk, there are refreshments - grilled vegetables, dips, cookies, and drinks. In this case, the drinks could be had in these really nice plastic cups (I didn't use one, of course, but I did see others use them). They were thick and solid, unlike those SOLO cups you might have had your last frat beer in. The plastic was clear and the plastic was fully transparent. I wondered, "Why would someone throw this away?" It seemed to me that if you decided to keep this plastic cup, it would probably last you a while, until it cracked or got crushed. You could have not one, but several drinks from this cup. You could keep the cup at your desk, and when you wanted a drink, you could fill it up and drink from it. In all senses, the cup was such that it made me want to keep the cups, and it made me want to tell others to keep their cups. But the cups were inevitably thrown away, after single uses.

Here are two pictures of cups. Which cup do you think is the plastic cup, and which one is the glass cup? I have cropped the bottoms, because the bottoms will give the answer away.

I guess it is still easy to figure out which one is plastic and which one is glass, but if you closely look at the cups, they have similar thicknesses, they function in the same way - both have the capacity and ability to hold liquids such that they don't leak. But it seems like there is something within us, likely socially defined, that makes us think that throwing away one of them is okay - people might call that one "disposable" - while throwing the other one away just doesn't make sense. I will try to think about why over the next few days.