We all have heard how power corrupts and absolute power corrupts absolutely. Probably more worrisome is that power stupefies and absolute power stupefies absolutely.
Although we have been taught that intelligence is an individual trait, it is to a large extend a communal one. Humans are social animals. What we know, what we decide to spend our time on, and what ideas we have are shaped by the people we socialize.
Yes, each person has a raw intelligence. But how effective it is depends on who their circle of peers are. I like to think about it this way: you might have bought a Ferrari that can go 210mph, but if you only drive around city streets, your effective max speed is 30mph.
Your effective intelligence is bound by who you socialize with and people feeling free to tell you that you are wrong. Assuming that you are surrounded by smart, intelligent people, let's explore how power can reduce your effective intelligence.
There are many facets to power, but one of them is the ability to harm people. If you are a supervisor, a manager, or an executive, you have the ability to harm people by firing them. You may never think in those terms, or even consider firing people for disagreeing with you, but the people with less power will interact with you aware of this possibility.
If you can't handle bad news, different opinions, or being told that you are wrong, your subordinates quickly will pick this up and adapt to it. If you crave attention and flattery, your subordinates will grant it to you.
Quickly the checks-and-balances of our human group disappears. Our human brains are weak, so we start to believe that we are smarter than we are. We are more likable than we are. That we are more competent that we are.
All of the above is well know. What does it have to do with intelligence? If you are wrong and are not corrected by others, you will stay in the wrong. You will hold onto incorrect ideas. You will stick to bad decisions. You are that Ferrari driving on a 10mph road.
So what to do? You need to build trust with your people that you can handle bad news and criticism. This is not easy, yet it is necessary.
Start by stating that you welcome comments on how to improve things. Then when those comments come in, you must stay calm and thank people for the feedback. Then you must follow through. This is tricky because you won't agree on proposed changes all the time. That is fine. You still should listen and implement changes frequently enough so that people trust that you are listening.
In short, learn to listen. Your intelligence depends on it.