... including why we favor more attractive people.
In cognitive psychology, there is a concept known as the "better-than-average" effect.
The basic idea of an "average" implies that 50% of people will be below average, and 50% will be above. However, when you ask people if they're below or above average when it comes to any particular skill (e.g., driving, singing), far more people will rate themselves as above average than the 50% that you might expect.
Even when we know about such cognitive biases, we often think of ourselves as being immune to them: Other people might fall into that trap, we think, but I'm too smart for that.
To optimize your thinking, let's examine those cognitive biases to which you believe you are immune. Here are 4 more:
1. Treating more attractive people better.
Attractive people tend to get evaluated more positively than less attractive people. If you're in a position to hire a new employee or choose a realtor or doctor, this is a good bias to be aware of. Also, since weight stigma remains very prevalent in our culture, it's useful to be aware if you're attributing any negative judgments to someone who is overweight—e.g., thinking they might be lazy. Another example might be the stereotype that someone who has tattoos might be unreliable.
The same principle applies to treating people who are more similar to you more favorably. Even when we're aware that this general bias exists, we often don't notice when it plays out in our lives—e.g., in a class, you might find study groups organizing themselves by ethnicity or age, or in your neighborhood, you might have a friendlier relationship with neighbors who are more similar to you than those who are different.
2. Thinking bad things won't happen to you.
You might know the statistics on how many people will get cancer during their lifetime, yet still think that your personal chance of contracting it is much lower. The key is recognizing your "average" vulnerability—to the extent that it's useful and motivates positive behaviors, such as getting a pap smear, carrying appropriate health insurance, wearing a seat belt, and using sun protection. Outside of the health sphere, similar examples include taking basic precautions to secure your home or prevent your stuff getting stolen.
3. Vulnerability to marketing and sales techniques.
Most of us know about the common sales and marketing techniques used by brands and salespeople. For example, "upsells" that get us to pay more for unneeded extras; credit cards and loyalty programs that use rewards and bonus offers to get people to spend more than they usually would; free trials that you don't get around to cancelling; and, in stores, putting the most expensive brands at eye level.
Which types of offers do you participate in but kid yourself that you're not getting influenced by sales and marketing techniques? There may be some strategies that don't cause you to change your thinking or behavior, but you need to be able to recognize when you are being influenced.
3. Our bias toward sticking to doing the same thing.
The more familiar something is, the more we tend to prefer it. When do you fail to recognize that you like something mostly because you're familiar with it—e.g., wearing black every day just because you're used to it.
4. Seeing people we're in love with through rose-tinted glasses.
When you're in a committed relationship, it's generally useful to see the best in your spouse or partner. It helps keep us happy in the relationship by convincing us that we made a good choice of partner, and it allows us to give our partner a break when they screw up—e.g., they do something stupid but we continue to see them as generally smart.
However, there can be times where we fail to recognize our partner's shortcomings when it would be useful to do so—e.g., you might allow them to talk you into something financially risky or unethical.
At the dating stage, love and lust can blind us as well, to the extent that we make a poor choice when a new partner's negative qualities come to the surface—e.g., your partner is a superficially charming narcissist. When would it be useful to you to recognize that your partner does have a weakness in a particular area—e.g., when they overestimate their driving abilities and drive too quickly when your entire family is in the car.