Great! Ok, Barbara... that helps to get some more information on his development. What you are describing is impulsivity, and this behavior is fairly common in two year olds! Also, it can sometimes be a precursor to some attention issues down the line, but this is not something that is generally diagnosed at this age due to how young the child is. Impulsivity is simply the inability to wait. Waiting for juice, waiting for your attention, waiting for circle time, etc. In kids who later develop a clear case of ADHD, there are structural differences in the brain that cause this impulsivity, and just for informational purposes, I am sharing this here: What causes impulsivity?
Some people may think that this trait is just a sign of a willful child who is trying to be bad. The next time a relative or neighbor gives you flack about your impulsive child, send them here to read the latest ADHD research.
If you think your child is wired differently, there is scientific truth to back up your gut feeling. The brain of a child who has ADHD may be different from child who does not have this disorder. In this Health Scout article, a study was cited where it was found that a part of the brain called the ventral striatum was smaller in children with ADHD than those children who do not have this disorder. The study, which was published in the journal Biological Psychiatry, concludes that this brain anomaly may be associated with symptoms of hyperactivity and impulsiveness in children having ADHD.
The neurology of ADHD is a fascinating topic and they are finding out new things all the time. In this Psychiatric Times report, you can read the details about high resolution MRI studies where they examine the ADHD brain structure. It seems that increases in the volume of gray matter in large areas of the brain such as the posterior temporal and inferior parietal cortices of children with ADHD may also play a part in symptoms such as inattention and impulse control.
Now, whether or not this becomes more focused and prevalent as he grows remains to be seen. What is important right now is to help teach him how to manage impulsivity. It is a LEARNING process that all adults must be on board with. I am attaching another great link with information about how to teach a child to wait: http://www.healthcentral.com/adhd/c/849319/73876/teaching-child-wait
Please let me be clear; I am not diagnosing your son in any way as having ADD/ADHD. The behavior that you describe has traits of the impulsivity that can accompany this type of issue, and so I am also attaching some information that will help to educate you on the behaviors itself: http://www.helpguide.org/mental/adhd_add_parenting_strategies.htm
My purpose in sharing this is to help you understand that there are behavioral training approaches that can help him, which are also used to help kids who are later diagnosed with attention issues. If you work with him now in a clear, instructive, teaching manner on slowing down those impulses, slowing down his movement where possible and rewarding the waiting, he will benefit all around. I hope this information gives you some ideas and please let me know if the articles are completely off base in terms of his behavior and impulsivity. It can be very difficult to give ideas and strategies without doing a behavioral observation of the child, and I want to be sure that I am understanding the behaviors you are seeing correctly!
Remember; all kids are wired differently, but that doesn't mean they are wrong or "bad"... and it is important for kids to grow up feeling special and valued for who they are, even those with the wiggles! Let's talk again after you've read the information, and until then, have a great day!