Ksy,
As your child is still young, some of the more obvious coping mechanisms that children with Asperger's develop may not have taken root yet (if he is in fact on the Autism Spectrum). I am a consultant specializing in Asperger's and Autism, certified in 2 interventions that have significantly improved the quality of life for children with various developmental challenges (HANDLE and Relationship Development Intervention).
I would be interested to know if your son does the following:
-points things out to you to share, then checks back with you nonverbally (this is key)
-notices your nonverbal reactions in the midst of interaction - for example, if you looked bored, or had no emotion on your face, how long would your son continue the activity before he noticed?
Do you find yourself asking him a lot of questions to keep the interaction going? This is often an unintentional overcompensation amongst caregivers/adults when interacting with children on the autism spectrum. Because the child is often not responding or initiating at a 'normal' pace, we compensate by prompting, asking more questions than we would to a typical child. As time goes on, and demands increase, children with ASD can experience more anxiety which leads to coping mechanisms like looking for 'sameness', predictability (asking caregivers questions to things they already know the answer to), and repetitive activities or thinking. Children who are happy and smiling sometimes can be mistaken for actually sharing facial expressions with others - so that is why it's important to test out the emotional feedback system by interacting with the child and deliberately communicating nonverbally to see if they notice. Language can be very deceiving, especially when we adults don't realize how much work we are doing to keep the interaction flowing.
If you are concerned with his social abilities, it might be a good idea to limit the exposure to activities he can create static thinking from - such as books. The website www.rdiconnect.com has some information about the type of thinking that is indicative of Autism/Asperger's Syndrome, and might help you get clarity on what you are seeing with your son. Most autism professionals believe speech and behavior are the issue - there are actually cognitive differences in children with ASD and very high-functioning children can be missed early on. Some people with Asperger's don't receive a diagnosis until late teens or adulthood.
I hope this helps!
April Choulat
P.S. If your son does end up with a formal diagnosis, don't let that sway your opinion of him - he IS spectacular! And contrary to some of the pessimistic feedback parents get from diagnosticians, innovative therapies are making a huge difference in the lives of people with ASD. Good luck:)