By Adam Jusko, ProudMoney.com, adam@proudmoney.com

Many of us think we’re too smart to fall for advertisers’ tricks. We won’t buy something because of a catchy jingle or famous spokesperson. But if you think those obvious tactics are the only things companies use to influence you, you are very much mistaken. And if you think you don’t fall for their tactics, you’re mistaken there, too.

  • For example, did you know that you’re more likely to change your buying behavior when you are a “nine-ender”? (As in, nearing a big age milestone, like going from age 39 to 40, which causes people to reflect on their life choices.)
  • Did you know you’re more susceptible to an advertiser’s message when you’re in a good mood? (Maybe that’s why Super Bowl ads are so expensive.)

No need to feel bad about this. You are human. Your brain does what other human brains do to make sense of the world. And your brain is usually pretty good at it. That’s why marketers have to work so hard to figure out how to work with your brain instead of against it.

The new book The Choice Factory, by Richard Shotton, lays out 25 “behavioral biases” that influence what we buy. While this book is actually targeted to those doing the advertising (to help them better influence what you buy), you can use it to understand what they’re doing and decide when and why you should resist. (Sometimes you shouldn’t resist. You have to buy something, right?) Also, there are a few lessons here for those working on their own “personal brand.”

Human behavior is interesting. You already know that stores price their goods at $3.99 instead of $4.00 because it feels significantly cheaper to your brain. But, even knowing what they’re doing, you often fall for it anyway. (Shotton call this the “left digit effect.”)

And listen to this: If a restaurant doesn’t use dollar signs on its menu (showing a meal price as 7 instead of $7, for example), sales go up by 8%. (This is similar to why casinos have you play with chips instead of actual currency, and why you spend more when paying with a credit card — the less you feel like you’re spending “real money,” the more of it you will spend.)

Knowing these behaviors and biases can help you spend more wisely. In addition, you can use some of these “tricks” when selling yourself. My favorite: “The Pratfall Effect.” This essentially states that a worthy product (or person) that shows off a small flaw is actually seen as more likable than something or someone that comes across as too perfect. Maybe the next time you’re in a job interview and you’re asked what your greatest weakness is, you should tell the truth instead of coming up with some BS answer like “I expect too much of myself.”

The psychology of why we act the way we do, even when we know it’s not in our best interests, is always fascinating. The Choice Factory will no doubt help marketers who want to exploit consumers’ behavioral quirks, but it also gives consumers the information they need to defend themselves — and even to use some of these tricks for their own benefit.