7 Things You Can Learn from 100 Years of Dumb Behavior

What are the most common dumb things that people do?

It isn’t about being “stupid” (although someone who does stupid things consistently might understandably get that label). I’m talking about the stupid things anyone is capable of doing (and that many often do).

These  seven behaviors, drawn from research and insights across psychology, sociology, and cognitive science over the past century, characterize stupid behavior:

1. Overconfidence in Knowledge and Abilities

One of the most well-documented cognitive biases is the Dunning-Kruger effect, where individuals with low ability or knowledge overestimate their competence. Overconfident people tend to take unnecessary risks, reject expert advice, and remain unaware of their limitations. This often leads to repeated mistakes, both personal and professional.

2. Refusing to Learn from Mistakes

A pattern of ignoring failures or blaming others is another hallmark of poor decision-making. While mistakes are common, intelligent individuals use them as learning opportunities. Stupid behavior often involves repeating the same actions, expecting different outcomes (akin to Einstein's definition of insanity).

3. Acting only on Emotion Rather Than Logic

Emotional decision-making, where feelings override rational thought, is a frequent characteristic of poor judgment. Impulsive decisions—whether in personal life, finances, or leadership—often lead to regrettable outcomes. Emotional reactions like anger, fear, or jealousy cloud clear thinking.

4. Groupthink and Herd Mentality

Groupthink, as defined by social psychologist Irving Janis, occurs when people conform to the opinions or behaviors of the group without critical evaluation. This leads to poor decisions, whether in business, politics, or social settings. The pressure to go along with the crowd can cause people to ignore evidence and act against their best interests.

5. Disregard for Expertise and Evidence

Today accepting misinformation and ignoring or dismissing expert knowledge is a behavior that's especially prominent among those with poor critical thinking skills. Whether it’s disregarding scientific consensus, falling for conspiracy theories, or rejecting advice from experts, refusing to consider evidence is a sign of intellectual rigidity. (And I acknowledge that all expertise is not equally valuable.)

6. Focusing on Short-Term Gratification

People who make decisions solely for immediate pleasure or gain, without considering long-term consequences, often find themselves in dreadful situations. The inability to delay gratification or think strategically about the future leads to financial problems, relationship issues, and health risks. 

7. Blaming External Factors Instead of Taking Responsibility

Stupid behavior often involves attributing failures to outside forces—other people, bad luck, or the environment—rather than taking personal responsibility. This lack of accountability prevents growth and self-awareness, perpetuating cycles of poor decision-making.

These behaviors are avoidable and awareness of them is key to developing better judgment and decision-making skills. We can improve our lives by avoiding these dumb mistakes. 

Doing something stupid doesn’t make you stupid if you recognize the misstep, correct it and learn from it so you don’t do it again.