From my first day of class I gathered the following insight about what baggage students bring with them to their first class in psychology.
1) Instinct determines many of our behaviors.
- WRONG. The key word is MANY. The list of bona fide instincts is short compared with the long list of what we learn. This view, like evolution & religion, is compatible with the view that evolutionary forces have impacted our development. As a species we are very flexible in response to environmental situations. I'd say that many animals are well-equipped to learn but are far from tabula rasa. Few have demonstrated Fixed Action Patterns, the closest to a scientific definition of instinct I can provide.
2) How a person demonstrates happiness depends on culture and upbringing.
-WRONG. Look at facial expressions of happiness. Around the world they are they same. Sure, we see some subtle cultural differences in the situations we show our emotion. Display rules govern when and where we'll actually smile when happy. If you're from MN or had MN parents, or have been married to someone from MN or raised by someone from MN, it may take a lot to make you smile! But when you do, you will move the same facial muscles that a Papau New Guinean who has never seen anyone from another culture moves. Read more about Paul Ekman's research on emotional expressions here.
3) Most of us would not follow instructions from an authority figure to hurt another person.
-WRONG. Take a look at Stanley Milgram's experiment. When he asked a bunch of his colleagues at Yale if his experiment was ethical, they said of course - no one will actually hurt anyone. Turns out most of them did. Milgram's experiment goes down as the most shocking one in the history of psychology.
4) The more motivated and aroused you are, the better your performance will be.
-WRONG. This is true, but only up to a certain point. For tasks that we know well and have practiced many times, a little arousal definitely helps. Not enough - you performance suffers because you're not as pumped. Too much - you choke under pressure. If you perform well under pressure, you've got an optimal level of arousal or are doing something that comes easy to you. If you choke under the pressure of a crowd, the arousal provided by an audience got to you.
5) We only use about 15% of our brains.
-WRONG. Although you probably believed your fourth grade teacher who first told you this because at the time s/he was the smartest person you knew, this is flat out wrong. Think abouit it this way: What would happen if someone scooped out 85% of your brain. You'd be less than a vegetable. It's possible to lose huge portions of one's brain as an infant and be fine. Young brains are very resilient. For a delightful story on the plasticity of young brains, check out this New Yorker Annals of Medicine story.