Why can someone who is good at complex reasoning still accept an obviously flawed intuitive answer?

Answer & explanation

Reasoning ability and the tendency to engage careful reflection are different

The ability to reason through difficult problems is not the same as routinely choosing to question a plausible first impression. Even mathematically skilled people can answer a trick problem impulsively if they do not check its constraints. Reflective thinking depends on habits of scrutiny and attention, not just intellectual capacity.