Here a passage out of Emergence: the Connected Lives of Ants, Brains, Cities and Software by Steven Johnson that I found intriguing:

What are you thinking about right now? Because my words are being communicated to you via the one way medium of the printed page, this is a difficult questions for me to answer. But if I were presenting this argument while sitting across a table from you, I'd already have an answer, or at least an educated guess-- even if you'd been silent the entire time. Your facial gestures, eye movements, body language, would all be sending a steady stream of information about your internal state-- signals I would intuitively pick up and interpret. I'd see your eyelids droop during the more contorted arguments, note the chuckle at one of my attempts at humor, register the way you sit upright in the chair when my words get your attention. I could no more prohibit my mind from making those assessments than you could stop your mind from interpreting my spoken words as language. (Assuming you're an English speaker, of course.) We are both locked in a communicational dance of extraordinary depth-- and yet, amazingly, we're barely aware of the process at all. Human beings are innate mind readers. Our skill at imagining other people's mental states ranks up there with our knack for language and our opposable thumbs. It comes so naturally to and has engendered so many corollary effects that it's hard for us to think of it as a special skill at all. And yet most animals lack the mind-reading skills of a four-year-old child. We come into the world with a genetic aptitude for building "theories of other minds," and adjusting those theories on the fly, in response to various forms of social feedback. In the mid-eighties, the UK psychologists Simon Baron-Cohen, Alan Leslie, and Uta Frith conducted a landmark experiment to test the mind-reading skills of young children. They concealed a set of pencils within a box of Smarties, the British candy. They asked a series of four-year-olds to open the box and make the unhappy discovery of the pencils within. The researchers then closed the box up and ushered a grown-up into the room. The children were than asked what the grown-up was expecting to find within the Smarties box-- not what they would find, mind you, but what they were expecting to find. Across the board, the four-year-olds gave the right answer: the clueless grown-up was expecting to find Smarties, not pencils. The children were able to separate their own knowledge about the contents of the Smarties box from the knowledge of another person. They grasped the distinction between the external world as they perceived it, and the world as perceived by others. The psychologists then conducted the same experiment with three-year-olds, and the exact opposite result came back. The children consistently assumed that the grown-up would expect to find pencils in the box, not candy. They had not yet developed the faculty for building model of other people's mental states-- they were trapped in a kind of infantile omniscience, where the knowledge you possess is shared by the entire world. The idea of two radically distinct mental states, each containing different information about the world, exceeding the faculties of the three-year-old mind, but it came naturally to the four-year-olds. ...Is it conceivable that this skill simply derives from a general increase in intelligence? Could it be that humans and their close cousins are just smarter than all those other species who flunk a mind-reading test? In other words, is there something specific to our social intelligence, something akin to a module hardwired into the brain's CPU-- or is the theory of minds just an idea that inevitably occurs to animals who reach a certain threshold of general intelligence? We are only now beginning to build useful maps of the brain's functional topography, but already we see signs that "mind reading" is more than just a by-product of our intelligence. Several years ago, the Italian neuroscientist Giaccamo Rizzollati discovered a region of the brain that may well prove integral to the theory of other minds. Rizzollati was studying a section of the ventral premotor area of the monkey brain, the region of the frontal lobe usually associated with muscular control. Certain neurons in this field fired when the monkey performed specific activities, like reaching for an object or putting food in it's mouth. Different neurons would fire in response to different activities. At first, this level of coordination suggested that these neurons were commanding the appropriate muscles to perform certain tasks. But then Rizzolatti noticed a bizarre phenomenon. The same neurons would fire when the monkey observed another monkey performing the task. The pound-your-fist-on-the-floor neurons would fire every time the monkey saw his cellmate pounding his fist on the floor. Rizzolatti called these unusual cells "mirror neurons", and since his announcement of the discovery, the neuroscience community has been abuzz with speculation about the significance of the "monkey see, monkey do" phenomenon. It's conceivable that mirror neurons exist for more subtle, introspective mental states-- such as desire or rage or tedium-- and that those neurons fire when we detect signs of those states in others. That synchronization may well be the neurological root of mind reading, which would mean that our skills were more than just an offshoot of general intelligence, but relied instead on our brains' being wired in a specific way. We know already that specific regions are devoted to visual processing, speech, and other cognitive skills. Rizzolatti's discovery suggests that we may also have a module for mind reading. The modular theory is also supported by evidence of what happens when that wiring is damaged. Many neuroscientists now believe that autistics suffer from a specific neurological disorder that inhibits thier ability to build theories of other minds-- a notion that will instantly ring true for anyone who has experienced the strange emotional distance, the radical introversion, that one finds in interacting with an autistic person. Autism, the argument goes, stems from an inability to project outside one's own head and imagine the mental life of others. And yet autistics regularly fare well on many tests of general intelligence and often display exceptional talents at math and pattern recognition. Their disorder is not a disorder of lowered intellect. Rather, autistics lack a particular skill, the way others lack the faculty of sight or hearing. They are mind blind."