Short Attention Span in Children
Attention span in children isn't really defined until he is about 3 or 4 years old. By the time he reaches preschool, your kid should be able to focus on one thing for about 15 minutes. Your 2-year-old, on the other hand, might only be able to concentrate for about three minutes.
If your kid is in preschool and can't pay attention for 15 minutes, he may have a short attention span and you may want to talk to your pediatrician. In some cases, a short attention span can be attributed to attention deficit hyperactivity disorder (ADHD). It's a difficult diagnosis to confirm and you shouldn't be quick to label your kid. There could be other things going on with your kid that might make it hard for him to concentrate. In some cases, a short attention span may be exacerbated on fatigue or too much television.
In fact, kids are naturally easily distractible and are constantly looking for the next fun thing to do. It's likely that as your kid ages, his attention span will increase. If it doesn't—or if you notice any other symptoms—you might want to get him evaluated for ADHD.