It starts when you're young. In fact, it's encouraged when you're young. You're given stuffed animals or little dolls. You're asked to name things around your house. Things are explained to you in terms of 'likes' and 'dislikes'. For example, I was told that the toilet dislikes having all my clothes flushed down it - apparently, that makes it 'sick'. The world is sketched out for you in terms of relationships, and inanimate objects have relationships as readily as humans do.
And then one day it stops. Thinking that a Christmas tree left out on the side of the road is 'sad' or that you owe an old pair of sneakers better than just dumping them in a trash can isn't indicative of a childlike sense of wonder, a lot of empathy, or a good imagination; it's just needlessly crazy. There's even a psychological disorder to describe the problem: Anthropomorphism.
The pathetic fallacy
The term was invented by Greek philosopher Xenophanes, who used it to describe the way that people thought their gods - the most unknowable things imaginable - resembled them and had their motivations. He noticed the way that Greek gods tended to be fair-skinned and blue eyed, while African gods had darker skin and darker eyes. People naturally gave their own characteristics to other things. As years progressed, this behavior fell from the heavens and came down to earth. Anthropomorphism wasn't just for the gods, it was for anything and everything around humans.
One of the most dramatic names for this behavior is the pathetic fallacy, which is not as judgmental as it sounds. This phrase was invented in the eighteen hundreds, and the 'pathetic' is meant to call to mind 'pathos' or drama. It refers to the poetic practice of ascribing human characteristics to inanimate objects. My personal favorite is, "The sea was angry that day, my friend; like an old man trying to send back soup at a deli." Unfortunately, not everyone has the light touch of a Seinfeld writer, and too much reliance on the pathetic fallacy was considered the hallmark of bad writing.
The pathetic fallacy has jumped over to bad science writing, too. It's happening when a writer tells you that gas molecules 'want' to flow from a high density to a low density area, or when researchers are too quick to ascribe human motivations to animal interactions.
(This, for example, is not a friendly smile.)
In psychiatry, anthropomorphism is considered a problem. It can be a rationale for obsessive compulsive disorders, like people who place all of their objects a precise distance apart for fear of the objects 'feeling' crowded. And when there is an erotic component to the idea, it's called objectosexuality (not to be confused with fetishism, which doesn't involve ascribing feelings to the desired item). Perhaps the most famous current example of this is Erika La Tour Eiffel, who married the Eiffel Tower.
Milder, more common anthropomorphism is thought to be caused by a need for control. Psychologists found that people tended to anthropomorphize unpredictable gadgets more than they did predictable ones. Snap on a light switch, the light turns on. There's no need for more thought than that. If, however, a computer tends to suddenly freeze, or randomly not save, or require starting several times in a row, people start unconsciously ascribing evil intent to it. It's easier to say, "Sometimes it likes to pull this kind of crap with me," than to face the completely unknown, uncontrollable, and unfixable hardware problem. We want to give things understandable motivations because we've got a human need for comfort.
Advertising and kiddie movies
Psychologists think anthropomorphism also demonstrates a need for social connection, and this idea has not slipped by advertisers unnoticed. Consumer research studies have noticed that people tend to be much more forgiving of gadgets if they have seen an anthropomorphized version of them. If someone has seen a product dancing around in an ad, it's easier to think of it as quirky instead of shoddy. It has a human face. That's comforting.
It also might be discomforting. People are less likely to trash a person than they are a thing. They might throw out a crappy toaster - they'd feel differently about Wall-E. Or, for that matter, Buzz or Woody, or Lightning McQueen, or any of the many other living, breathing, feeling characters that they're exposed to these days. Anthropomorphism in movies is big business, from menacing characters like HAL, to ridiculously adorable ones like Wall-E. Maybe that's because they're playing into what we've always suspected; that everything around us is watching us. And if we play our cards right, they're on our side.