[quote=AlexsMomAny chance that, when faced with more-challenging work, your DS is choosing to fail by not trying, rather than risk trying and failing? ("I could have done it, if I'd wanted to" rather than actually doing it, when failure is an option? And "failure" could be a very high threshold - my DD considered an 80 on an AR quiz to be a failure, and picked a book 2+ levels lower as her next one.)[/quote]

This was my gut reaction. Didn't he switch from a regular school to a gifted school? If so, he may be feeling much more challenged (not by the work necessarily, or all of it, but by the environment and other kids) and using this as a defense mechanism. And a school that gives letter grades to 8 year olds kind of doesn't help in that regard.

You might need to "overparent" for a while to break the cycle? Make sure the homework is complete and turned in (maybe that means having the teachers adjust the homework load, maybe that means figuring out how to keep him on task, or making sure he knows there is nothing fun until it is done). If there has really been no hint of this sort of behavior before, could there be some classroom dynamics that encourage it (is he making friends by being the class clown at his new school)?

And being gifted is no excuse for crummy manners to adults or parents, rudeness, smugness, disruptiveness, etc. So that is an issue you will want to address in your own way, depending on how you parent such issues. I will be a mini-me Grinity and echo her suggestion for the Nurtured Heart approach, it worked for us.