Please help with my negative 8yo

[IsabelleSE19]

So I am at a bit of a loss. My 8 yo DS is a healthy, bright child from what I hope is a loving and supportive household. But sometimes he has this terrible negative attitude towards himself, saying that he's no good at anything, and often won't even try to do new things.

For example, he got a beautiful bike for his birthday but we can hardly even persuade him to sit on it, because he doesn't believe he'll be able to ride it. His 5yo sister, meanwhile, takes everything on with a 'can-do' attitude (sorry, hate that phrase but it seems apt here!) and has learnt to ride her bike already.

It's like he would rather not try than risk failing. I don't think he's quite the same at school, but then he is very good academically so maybe it's different in that environment.

Me and DH have tried to talk to him and encourage him, but he would rather just stay in his miserable negative spiral, it seems. Has anyone else had a DC like this, and if there are any tips to boost confidence or change his attitude, please do send them my way! TIA

Just make sure that you’re only praising him for trying, rather than achieving.
Show him that “success” isn’t necessarily dependent on outcomes.Success can mean a willingness to try, put forth your best effort, and show gradual improvement.
When he does take a risk, point out that you’re proud of his bravery, and he’ll be even more willing to try something new in the future.
Ask questions such as "Have you always been able to do this? How did you learn to do this? How did you get better at this skill?” This reinforces the point that none of his abilities have been acquired overnight, and it may give him the courage and motivation to try something new.
Help him shift his perspective by keeping an adventure diary. In the diary, he can write about all the adventures had as a result of trying new things.

Thank you for the very thoughtful advice. Maybe we could try and set an achievable target like trying five new skills before December or something. I had been planning to teach him how to do a bit more independently in the kitchen, so that might be a good place to start.