Just because you know what you should do, doesn't mean that you're going to do it. You may know that it would be smart to lose weight, but aren't on a diet. You may be convinced that when you're feeling tired during the day you should do jumping jacks to boost your energy, but instead you lie down on the couch. You may know that using a formal decision making procedure is a good idea when you're t...

Suppose that you'd like to make fewer mistakes. How do you go about actually learning from the ones you've already made, rather than repeating them? The first step is to admit to yourself that you've made a mistake. Trivial errors, like accidentally putting the container of orange juice in the freezer, are easy enough to come to terms with. But for more serious matters, or matters that involve pr...

Why do people who hate that they overeat keep overeating? Why do people who know that their girlfriends or boyfriends are bad for them keep taking these girlfriends and boyfriends back? Why do so many people who want to go to the gym never actually bother to do it? These circumstances can be explained, at least partially, in terms of desires changing and conflicting with each other. What we wan...

Looking back on our decisions, we generally feel as though we can explain them. Why did we hire that candidate instead of this one? Because he was clearly more qualified for the job. Why did we go on a date with that person and not the other one? Because he or she seemed nicer. Why did we sentence that criminal to a harsher sentence than this other one? Because she committed a more damaging crime....

Most of us know we are great. We easily see our own potential, goodness, and areas of skill. We're sure we have strong justifications for our behaviors and beliefs. When things go wrong for us, it usually isn't fundamentally our fault. When things go well, we know we deserve the credit. Just ask people. In a poll of high school seniors, only 2% thought they were below average in leadership abil...

For each dataset, there is a limit to what we can use that dataset to test. Using the standard p-value based methods of science, the more hypotheses we check against the data, the more likely it will be that some of these checks give inaccurate conclusions. And this presents a big problem for the way science is practiced. Let's take an example to illustrate the principle. Suppose that you have ...

Your beliefs form something like a temple. The temple has many columns, rooms, and towers. The columns are facts and reasons that support the rooms. The rooms of the temple represent your major beliefs. The towers correspond to beliefs that build on each other. For example, you have rooms corresponding to aspects of your moral philosophy. On top of these rooms, supported by your moral philosoph...

In order to make predictions, your brain must have a model of reality. This model is necessarily much simpler than reality itself. To see why, imagine that you are about to drop a baseball from waist height. Your brain can't possibly know enough about the atoms composing that baseball and the air around it to simulate what will happen at the atomic level. And even if your brain did have accurate k...