作者： chenchen

The Dunning-Kruger Effect: Why Incompetence Begets Confidence

Meet Dave. After a year of creating campaigns for a marketing company, Dave is convinced that his advertising skills are the best in his department. In his mind, his incredibly original content warrants a nice bonus. But when his manager hands him an annual review, his face falls. “This isn’t right,” Dave says, incredulous. He points at the section that marks him at the bottom 25 percent of employee performance and asks if it’s a mistake.

Dave’s case illustrates a psychological phenomenon called the Dunning-Kruger effect.

The Dunning-Kruger effect, coined by the psychologists David Dunning and Justin Kruger in 1999, is a cognitive bias in which poor performers greatly overestimate their abilities. Dunning and Kruger’s research shows that underperforming individuals “reach erroneous conclusions and make unfortunate choices, but their incompetence robs them of the ability to realize it.” This incompetence, in turn, leads them to “hold inflated views of their performance and ability.”

To reach these findings, Dunning and Kruger conducted a study that tested participants’ abilities in humor, logical reasoning and grammar. Before showing the participants their scores, Dunning and Kruger had them judge their performance on a percentile scale. What they found across all three categories confirmed their prediction of self-inflated assessment among underperforming individuals: participants scoring around the 15th percentile evaluated their percentile placements to be approximately 50 percent higher. And although results also indicated a slight overestimation by the average-scorers and a slight underestimation by the top-scorers, Dunning and Kruger focused on investigating the substantial overestimation by the bottom-scorers.

Were the underperforming individuals unable to recognize competence due to their own lack of it? To address this, Dunning and Kruger invited back the bottom-scoring and top-scoring participants and gave them the other participants’ tests to grade. Afterward, the participants were asked to re-evaluate their original testing score. The bottom-scorers, instead of recognizing their underperformance and lowering their rank accordingly, continued to elevate their scores. This suggested that the bottom-scorers needed competence to perceive competence.

If it takes competence to be aware, how are underperformers supposed to recognize their own lack of ability? The answer is in the question itself. Because it takes competence to be aware, underperformers must become competent. After training the bottom-scorers in logical reasoning, Dunning and Kruger discovered not only that their scores improved, but also that they no longer inflated their scores. These results indicate that knowledge and experience are crucial for gaining both ability and self-awareness.

In essence, we can’t reach a high level of competence without actively seeking feedback and knowledge. And for any activity — whether it’s marketing, parenting, football or underwater basket-weaving — it takes an open mind to gain the experiences that help us see our mistakes and grow from them.

The hallmark of intelligence, according to Dunning, is being “good at knowing what we don’t know.” If we want to avoid the impact of cognitive biases such as the Dunning-Kruger effect and if we want to better ourselves overall, it’s vital that we’re aware that there is always more to know.

Works Cited

Cherry, Kendra. “The Dunning-Kruger Effect.” Verywell Mind, 14 June 2019.

Kruger, Justin, and David Dunning. “Unskilled and Unaware of it: How Difficulties in Recognizing One’s Own Incompetence Lead to Inflated Self-Assessments.” Journal of Personality and Social Psychology, Dec. 1999.

Morris, Errol. “The Anosognosic’s Dilemma: Something’s Wrong but You’ll Never Know What It Is (Part 1).” The New York Times, 21 June 2010.

Circadian Rhythms: The Conductor of Our Body’s Symphony

Our bodies are like musical compositions, different instruments completing the whole piece. The heart is the percussion, keeping pace for the rest of our bodies. The digestive system is the bass, providing the foundation everything else body systems need. The brain is the piano, giving us life and coordination. But who is the conductor? To whom do we owe the perfect synchronization of all instruments? The mastermind may come as a surprise, but the miracle-worker of our bodies’ symphony is the circadian clock — a series of molecular cues which integrate external stimuli to keep our bodies’ cycles on a 24-hour schedule.

Our mastermind’s lair is a compartment of the brain called the suprachiasmatic nucleus (S.C.N.), containing only 50,000 of the 86 billion neurons in our body. Our eyes detect light, signaling directly to the S.C.N., as if the conductor were being cued by the mood of the audience. During the day, high intensity light signals the S.C.N. to produce the proteins period (Per) and cryptochrome (Cry), which in turn activate myriad downstream pathways controlling metabolism, sleep and overall activity level. Meanwhile, Per and Cry accumulate in the cytoplasm, reaching critical levels at which they translocate to the nucleus and bind to receptors that shut down the production of Per and Cry. This slows metabolic activity and prepares the body for sleep.

This diurnal feedback loop is the crux of homeostasis, or biological equilibrium, but all musicians know what can happen when the conductor of the orchestra misses a beat. For instance, when we experience jet lag after flying between different time zones, our circadian rhythms are disrupted because our S.C.N.s receive light signals that are out of register with our previous protein accumulation cycles.

Additionally, circadian rhythm disruptions have been linked to obesity. Scientists compared light pollution data across the United States, and brightly-lit urban areas have significantly higher obesity rates. Further studies revealed that a hormone called leptin, responsible for appetite suppression, is regulated by the circadian clock. During the day when activity and energy requirements are increased, leptin expression decreases and thus we eat. When our circadian clocks are disrupted, leptin expression is lower, resulting in abnormally increased appetite and obesity.

A dive into the rhythmic inner-workings of our bodies can help explain why you have a bad night’s sleep after watching Netflix late at night, or why staying inside all day makes you less hungry. Dysregulated circadian rhythms may cause neurological disorders including Alzheimer’s disease, so further study of this symphony may offer potential treatments. Now, as the orchestra quiets and the conductor bows, scientists applaud the small compartment of our brain that keeps our bodies in sync.

Works Cited

Fonken, Laura K., and Randy J. Nelson. “The Effects of Light at Night on Circadian Clocks and Metabolism.” Endocrine Reviews, 1 Aug. 2014.

Froy, Owen. “Circadian Rhythms and Obesity in Mammals.” ISRN Obesity, 18 Nov. 2012.

“Jet Lag — Overview.” American Academy of Sleep Medicine.

Ko, Caroline H., and Joseph S. Takahashi. “Molecular Components of the Mammalian Circadian Clock.” Human Molecular Genetics, 15 Oct. 2006.

Nagourney, Eric. “Some Rhythmic Clues to Alzheimer’s.” The New York Times, 17 April 2001.

Sanders, Laura. “Out-of-Whack Body Clock Causes More Than Sleepiness.” Science News for Students, 3 Dec. 2019.

The Motion of the Ocean: Using Sea Waves to Desalinate Seawater

One of the most famous divine punishments in Greek mythology is that faced by Tantalus, who was condemned to an eternity of hunger and thirst despite standing in a pool of water below a fruit tree. Humanity seems to be in a situation not too far from Tantalus’s: Although our planet’s surface is 71 percent water, nearly all of it is too salty to drink. According to the World Resources Institute, a quarter of the global population is at risk of running out of fresh water. While seawater desalination methods exist, they have largely been too expensive and energy intensive to be practical, especially in regions where both freshwater and reliable energy sources are in short supply. But what if we could use the ocean itself to power seawater desalination?

In Cape Verde, an island country off the coast of Senegal, water is more expensive than anywhere else in Africa. Despite being surrounded by ocean, Cape Verdeans are facing an extreme water shortage. Eighty-five percent of the country’s water is processed through diesel-powered desalination, which is both expensive and environmentally unfriendly. However, the situation may soon change. In collaboration with IMAR, the National Maritime Institute of Cape Verde, researchers from a company called Resolute Marine Energy are testing a new desalination process on the Cape Verdean island of São Vicente.

This novel technology, aptly called Wave2O, harnesses wave energy to power a reverse-osmosis desalination system. Complicated as it may sound, reverse osmosis desalination is simply a way of filtering water through a membrane that removes salt and other unwanted particles. Pushing the seawater through the membrane requires a significant amount of energy — a potential problem in a country with limited electrical grid capacity — but Wave2O bypasses this issue by converting energy from the sea.

Water moves with incredible force. It can wreck ships, wipe out entire villages, and even carve through land to form massive canyons. If you have ever been wiped out while surfing, you know how powerful ocean waves can be. Wave2O takes advantage of this natural and renewable power source through a multiple step process known as wave energy conversion. First, ocean waves move flaps attached to the sea floor. The motion of the flaps then powers hydraulic pumps, which send high-pressure seawater through a reverse-osmosis desalination system.

In addition to being less expensive than diesel-powered desalination, Wave2O is also far more sustainable. According to Olivier Ceberio, the co-founder of Resolute Marine, replacing Cape Verde’s diesel-driven desalination systems with Wave2O could lower carbon emissions — a key driver of climate change — by over 4,000 tons per year. Theoretically, Wave2O could even be used to generate electricity, thereby providing developing countries and other communities in need with both freshwater and a sustainable power source.

Depending on how well Wave2O performs in Cape Verde, Resolute Marine’s technology could be used to desalinate seawater in coastal areas all over the world, thus unlocking one of this watery planet’s most plentiful resources. Through scientific innovation, perhaps Tantalus can finally quench his thirst.

Works Cited

Frisch, Lucy. “Addressing Water Scarcity with Ocean Waves.” Spring Nature, 4 June 2020.

Hurley, Bill. “Create the Future: Water Desalination, Powered by Waves.” Tech Briefs, 4 Oct. 2019.

Sengupta, Somini, and Weiyi Cai. “A Quarter of Humanity Faces Looming Water Crises.” The New York Times, 6 Aug. 2019.