If you feel a gut reaction after meeting a hire, it's probably System 1 thinking.
But you can mitigate the risk of hiring the wrong person by engaging System 2 thinking. Check their references. Ask probing questions. Validate your gut reaction with other members of your team.
The trick is to be aware of switching from one system to the other. It’s useful to understand when you are thinking on autopilot, when you are paying attention and what's inside your mental toolbox.