Not using common sense
Before You Begin
Pause and breathe. Even if this shouldn't be happening... accept that it is and embrace it with composure and calmness.
Calmness is the only way forward because without calm, there is no possibility for receptiveness and connection. Your child won't give to you any more than they see from you.
Never forget that a strong connection is fundamental, as there will be no correction in them if there is no connection with you.
The Core Problem
An underdeveloped ability to focus in the moment, and quickly imagine how their decision will play out.
What Will Make It Worse
Reacting with frustration or criticism when the child struggles to use common sense will only make them feel bad, plus it will lower their self confidence and willingness to practice critical thinking in the future.
What The Child Needs
1. To practice their critical thinking: Either in the moment, or using made-up scenarios, teach the child to first think of different ways to react to or handle a situation, then to imagine how each option would play out in good and bad ways, and finally which single option will have the best outcome.
2. Guidance and support: Provide guidance and support as the child practices using common sense in different situations. Help them think of additional considerations to determine what is the right action to take, so that they can remember them to better analyze on their own next time.
3. Emotional safety: Create a safe environment where the child can express their thoughts and ideas without fear of judgment.
How To Have The Conversation With Your Child
Find a good time to sit with them in a comfortable place that is free of distractions.
Share with them that you have seen them say some really smart things before, but you have noticed that sometimes in the moment they don't always think things through and end up doing something that wasn't the best idea.
Let them know that thinking on your feet and making good decisions is a great skill that isn't very hard, and you want to spend some time with them practicing that skill, almost like practicing basket shots [or any other activity they are in to], because you want them to have that skill too. [The point here is to get them excited about feeling smart and having a new skill]
Next start working with the child on the "What The Child Needs" pointers listed above.
Over the following weeks, find opportunities for the child to exercise their common sense/critical thinking muscle and have them help you think through something you are dealing with as a team. Additionally, car rides are a great time to think of different scenarios and practice critical thinking.
Feeling smart and being viewed as smart are universally enjoyed by people, and kids are no different. Play to this appeal and getting them to put in the work and successfully overcome their past common sense struggles should come pretty easy.