If you have never heard of the Dunning Kruger effect, neither had I till a couple of days ago. However at the Rick Mahorn Big Man Camp (www.bigman.camp) we have encountered it rather often.
This phenomenon refers to someone with limited knowledge or a deficit in skill level in a certain area who greatly overestimate their own ability or competence. Owing to either matters of ego (what we call hubris) or simple not enough experience with the area under consideration, they don't know any better or otherwise are motivated to overassess their ability. Lacking expertise coupled with ( or sometimes resulting in) lack of self-awareness, they consider themselves more accomplished than they are. Another word for this is having a blind spot.
In a teaching camp such as the Rick Mahorn Big Man Camp, the problem is that players who show this trait are reluctant or even resistant to accept correction or coaching, thinking that they know better.
As noted above, we typically get 2-3 such players at each camp.
One year we had a 7'4" D1 college player who the coaches felt had the requisite ability to make it in the NBA but he thought he was better than he was. He also did not have a good work ethic (possibly correlated to thinking he was already so great). So he might have gone on to play in the NBA but instead he ended up leaving basketball after college.
Another year we had a player who bristled at our first day's practice, which tends to feature a lot of conditioning skills and also basic drills such as the Mikan Drill.
The next day the player's father called me to say his son was not pleased with what he was getting out of the camp. I replied to the dad, "Naturally we want to work with him to make the camp the best experience for him that we can, but if he can't do Mikan drills with complete focus and high intensity that how is he going to have those qualities when he needs them in a game?" When the player ended up pulling out of the camp (the only time that ever happened in our 12 years to date) another player who knew him from growing up together said, "He always thought he was better than everybody else."
One summer we had a guard (since our original inception as a big man camp, we have evolved, just as the game has evolved, and now run a Guard Camp together with the Big Man Camp) who had a very cocky aggressive style of play that often served him well on the court. However every single coach noted that when they offered him corrections he was not interested. On the last day of camp I told him this quality could be very useful on the court, but off the court it would most likely keep him from growing as a player. A year later he came to visit us and it was clear we hadn't been able to get through to him.
A few years ago, while serving as Director of Sport Psychology at Florida Atlantic University, I was working with the women's softball team. In one activity I asked each one to list the 5 qualities they considered most important for their growth and success as a player, including technical things like hitting and fielding, and mental things like focus and confidence. One of the qualities that was mentioned quite often was one I hadn't considered, i.e. humility. They were talking about being coachable. This particularly noteworthy because the head coach was Joan Joyce, of whom ESPN noted
"Softball legend Joan Joyce famously struck out Hall of Fame baseball player Ted Williams during an exhibition game in Waterbury CT on August 5, 1961. Facing a crowd of 17,000, Joyce compeletel baffled the MLB star with her trademark drop-balls and curves, leading Williams to famously call her the greatest pitcher he had ever faced."
To sum up, players who are able to keep their ego in check, who have a certian level of humility, and who are open to the idea that their lack of experience and expertise may lead them to overestimate their abilities, are players who are more likely to grow as athletes in achieving great skill mastery, and beyond that, the wisdom of how to execute those skills in the high pressured moments of competition.
