Psychology 101: Intro to Psychology

If the above player doesn't work, try this direct link.

What do psychologists have to think about when designing studies and interpreting results? In this lesson, you'll explore how the scientific method can help with the difficult task of studying behaviors and their potential causes.

We are all capable of speculating about other people's behavior. We do it every day. That man who took my parking space is clearly arrogant and inconsiderate; that little girl screaming in the grocery store clearly has bad parents. But as normal as it is for us to make these kinds of assumptions and explanations, there is nothing reliable or scientific about any of it. Our spotty observations of little girls in grocery stores can't lead to any larger conclusion about the relationship between parenting and behavior.

Psychology attempts to apply the scientific method to the study of human thought and behavior in order to reach conclusions that do have real explanatory or predictive power. Psychologists come up with a hypothesis about people--that overly indulgent parenting leads to temper tantrums, for example--and then try to design a study that will show it to be right or wrong. There are many different kinds of studies, but all face the common problem of separating out the behavior you want to study from all the other kinds of behaviors that might happen along with it and the potential cause from other things that could cause it.

Let's say you want to design a study to see whether parents who give into their child's every wish are likely to have children that will have tantrums. You might ask parents to fill out a questionnaire to determine their parenting style; you then ask those who were especially indulgent and permissive to bring their child in to participate in a test of their ability to solve math problems. You tell them they'll get a candy bar as a reward for doing well. You don't really care about the children's math ability--that's just the pretense for getting them into your study. What you really care about is their behavior during the test. When they've finished, you look in your desk and then, in mock surprise, say 'well it looks like we're out of candy! Let me go ask a colleague if he has any.' You leave the room for about five minutes, come back still emptyhanded, and apologize for not having any candy.

Though some of the children seem disappointed but okay, many of them start to cry and demand candy. Once you've taken note of the reaction, you have a friend run in breathlessly with 'the last candy bar' and the children leave your study munching happily.

You take a look at the numbers; 80% of the children exhibited some kind of 'tantrum' behavior when they found out they really weren't getting candy. You conclude that, just as your hypothesis stated, indulgent parents are associated with bratty children.

But if you stopped here, you would have ignored one of the most important ideas in scientific testing: the scientific control. Your study design does seem to distinguish between different potential behavioral reactions to a common situation: some kids cry, and others don't. But your study doesn't distinguish between potential causes; all of these children have indulgent parents, but you can't be sure that it's indulgent parenting and not some other factor that causes 80% of them to cry. To help determine this, you'd have to bring in an equal number of children selected randomly and submit them to the same test; this is your control group.

You find that about 80% of these kids cry as well when they're denied candy. This means that your original conclusion, that indulgent parenting is associated with bad behavior, is actually not supported by the results; all you can really say is that being denied promised candy makes a significant portion of all children cry. There are two possible explanations for this: one is that parenting style has nothing to do with behavior. The other, perhaps more likely explanation is simply that your study upsets children too much to learn anything valuable from it.

Think of some tests you've taken--some are really easy, like a math test in which the only question was 1+1, and everyone who takes them gets 100%. Getting 100% on the test doesn't have very much to do with your preparation or your intelligence--it has more to do with the question being really easy. But if you're given a harder math question, like finding the integral of 2n, your score means more; if only a few people are getting 100%, this probably means that they have prepared better than everyone else. Promising kids candy and then refusing to give it to them is like the really easy test--most of them cry, but that's probably just because it's a really upsetting situation. If you designed a milder scenario that didn't cause as many tantrums, it might be able to tell you more about the differences between children who still did have tantrums and those who didn't.

This parenting style/children's behavior/candy bar test is made-up, but it should give you some idea of the questions that psychologists have to ask themselves when designing studies and interpreting the results. The principles of the scientific method are very important for psychologists, who come up with hypotheses about behavior and then try to prove them right or wrong. Scientific control is crucial to getting results that sufficiently pull apart different potential behaviors and causes.