Scientists have produced evidence that self-awareness is a big problem for people with autism.
Sophisticated scans showed the brains of people with autism are less active when engaged in self-reflective thought.
The findings provide a neurological insight into why people with autism tend to struggle in social situations.
The study, by the University of Cambridge, appears in the journal Brain.
Autism has long been considered a condition of extreme egocentrism.
But research has shown the problem is people with the condition have trouble thinking about, and making sense of, themselves.
The researchers used functional magnetic resonance scans to measure brain activity in 66 male volunteers, half of whom had been diagnosed with an autistic spectrum disorder.
The volunteers were asked to make judgements either about their own thoughts, opinions, preferences, or physical characteristics, or about someone else's, in this case the Queen.
By scanning the volunteers' brains as they responded to these questions, the researchers were able to visualise differences in brain activity between those with and without autism.
They were particularly interested in part of the brain called the ventromedial pre-frontal cortex (vMPFC) - known to be active when people think about themselves.
The researchers found this area of the brain was more active when typical volunteers were asked questions about themselves compared with when they were thinking about the Queen.
However, in autism this brain region responded equally, irrespective of whether they were thinking about themselves or the Queen.
Researcher Michael Lombardo said the study showed that the autistic brain struggled to to process information about the self.
He said: "Navigating social interactions with others requires keeping track of the relationship between oneself and others.
"In some social situations it is important to notice that 'I am similar to you', while in other situations it might be important to notice that 'I am different to you'.
"The atypical way the autistic brain treats self-relevant information as equivalent to information about others could derail a child's social development, particularly in understanding how they relate to the social world around them."
Dr. Gina Gómez de la Cuesta, of the National Autistic Society, described the study as "interesting".
"We know many people with autism do want to interact with others and make friends but have difficulty recognising or understanding other people's thoughts and feelings.
"This research has shown that people with autism may also have difficulty understanding their own thoughts and feelings and the brain mechanisms underlying this."