Evolution and Theory of Mind
If evolution is correct -- and science holds that it is -- then traits or abilities that are found among related species suggest that these traits survived natural selection. Crudely put, the trait was found beneficial to the survival of the species and therefore those members who carried the trait lived to reproduce and pass it onto their offspring.
Such is the case with theory of mind. Indeed, the term was first coined in a 1978 paper by primate researchers who concluded that higher apes like chimpanzees couldn't understand the mental states that lead to action on others' parts, though later research has found that they likely can [source: Call and Tomasello].
So what is the evolutionary benefit of theory of mind? As communications professor Francis F. Steen describes it, by considering others' motives to predict their actions, an animal can determine whether a predator is moving toward it to attack and eat the animal. Conversely, when it appears the predator is too hot to move on a particularly warm day, such a mechanism allows the animal -- which is likely hot too -- to rest easy as well and not expend any unnecessary energy running away from a predator that has no interest in pursuing it [source: Steen]. Anyone who has seen footage of a lion and a gazelle lying down, panting and watching one another only yards apart has seen this mechanism in action.
This ability has served humans as well. Yet cognitive researchers don't necessarily think that animals like gazelles and lions possess the capability of theory of mind. Most consider only humans and most likely higher apes in possession of this far more advanced intellectual analysis. More to the point, if you've ever looked at a lion and considered that it looked happy or that it wished it were free, you've just proven yourself capable of the kind of higher order thinking that theory of mind is based on.
There are rivals to theory of mind in explaining how we learn to predict others' behavior. One of these follows the animal model. The concept of mental simulation says that we predict others' goals and actions based on creating mental constructs of what we would do if we were in their shoes. We use our past experiences to construct a mental model of the situation, essentially using our brains' processing power to analyze the available data and then make our prediction.
Theory of mind goes much farther than mental simulation in imaging how we read the minds of others, and it finds support in the study of autism.