In a series of experiments, students were asked to rate their knowledge of everyday objects. The students were overconfident until they had to write out step-by-step explanations. Then they realised how little they understood.

Overconfidence often stands in the way of change. But if you point out someone's ignorance directly, they may get defensive. A better way is to let them recognise the gaps in their own understanding.

Stubbornness is an obstacle to changing people's opinions. Stubborn people will outright reject forceful arguments. They think outcomes can be subject to their will.

Instead of giving answers or forceful arguments, ask questions. This way, you're not telling your boss what to think or do. Questions like "what if?" and "could we?" can make people curious about what's possible.

Narcissistic leaders believe they're superior and special, and don't want to be told they're wrong.

Careful framing can coax them toward admitting they're flawed. Praise them first, but in a different area from the one in which you hope to change their minds. We all have multiple identities. When we feel secure about one of our strengths, we become more open to accepting our shortcomings elsewhere.

Disagreeableness is a trait often expressed through argumentativeness. Disagreeable people are determined to squash the competition. When you want them to change their mind, you become the competition.

Because disagreeable people are energized by conflict, they don't want you to bend to their will immediately. They want you to fight for your ideas.