Wikipedia
Mind-blindness can be described as a cognitive disorder where an individual is unable to attribute mental states to the self and other. As a result of this disorder the individual may be unaware of others' mental states, or incapable in attributing beliefs and desires to others. This ability to develop a mental awareness of what is in the mind of an individual is known as the Theory of Mind (ToM). This allows one to attribute one's own behaviour and actions to various mental states such as emotions and intentions. Mind-blindness is associated with autism and Asperger's syndrome (AS) patients who tend to show deficits in social insight. In addition to autism, AS, and schizophrenia, ToM and mind-blindness research has recently been extended to other disorders such as dementia, bi-polar disorders, anti social personality disorders as well as normal aging.
Generally speaking, the "Mind-blindness" Theory asserts that children with these conditions are delayed in developing a theory of mind, which normally allows developing children to put themselves "into someone else's shoes, to imagine their thoughts and feelings." Thus, autistic children often cannot conceptualize, understand, or predict emotional states in other people.