Aleksandr Kogan Ph.D.

The Critical Optimist

Should You Use Psychological Findings in Your Own Life?

User beware.

Posted Mar 04, 2012

Psychology is a funny science. On the one hand, it deals with questions that are perhaps the closest to our daily lives. Happiness, relationships, mental health—just to name a few—are topics of paramount importance to virtually all people (living at least), and these are precisely the phenomena that psychologists investigate. Thus, it's no surprise that there is a great interest in taking the insights gained from psychological research and applying it to our own lives. If writing about one's blessings in a journal everyday is found to predict increases in happiness and decreases in depression (as is indeed the case), why not start writing in my journal again?

The issue is the other hand. While psychology deals with questions intimately related to our daily lives, the field is extremely far away from providing answers to specific individuals. Virtually all research in psychology goes like this. We recruit a large number of people (typically between 100-500). We then have them answer different questionnaires or go through experimental conditions. We then see how different questionnaires are related to one another or how people in the different experimental conditions differ from one another. All of this though is on average. I'll stress this phrase again because its so critical: on average. Almost in no study is the effect present for every participant or every group of participants. In fact, in many studies, there are participants that go completely against the expected effect! The quick take home lesson here is that we should be extremely careful in applying what happens on average to a particular individual (this is called the ecological fallacy). Now lets examine why.

Relationship between satisfaction with life and depression

Lets look at a visual example. The figure I've included in this post is real data from roughly 100 participants—each dot represents a person's real scores. My colleagues and I had the participants complete two measures: satisfaction with life and depression. It should require little convincing that these two aspects of mental health should be negatively related—the more satisfied you are with your life, the less depressed you should be.

This is precisely the general pattern that emerges, which is captured by the down-trending line in the figure. This line can be thought of as the best fitting line for the data. It represents what is happening on average. But imagine you don't care about what happens on average. You care about what happens to you or another very specific individual. Then we have to become concerned about each dot. This is where the trouble arises. For virtually every value of satisfaction with life, people's depression scores vary quite a bit. For example, look at people with a satisfaction with life value of roughly 5. Some people have very low depression scores (around 1), while others are much higher (around 2.5). Then we have some really extreme cases—the most depressed (3.5) person in the entire study also has a very high satisfaction with life score (greater than 6)! If I know only your satisfaction with life score, there's no way for me to know which of the dots you will be—whether you are the person who is not at all depressed or the person who is very depressed at this same value of satisfaction with life. The take home lesson here is that while on average it is indeed true that greater satisfaction with life is related to lower depression, this may or may not be true for specific individuals. 

But why does this happen? People are ultimately extremely complex and psychologists are only beginning to scratch the surface of that compelixity. There are no solutions that will work for everyone—and often no solutions that will even work for a majority of people. There are simply too many other factors that are affecting who you are, how you feel, and how you behave for simple models such as the one above to be truly helpful in understanding a particular person. People are idiosyncratic; these particulars are going to affect how positive or negative an effect a particular psychological manipulation has on you. Our models are wonderful on average where all these idiosyncratic differences between people get washed away, but the idiosyncracies are critical when considering the specific individual. 

In the end, many of psychology's findings will be helpful to you. But in attempting to apply particular findings to your own life, you have to make the careful judgment of does this work for me or not. It's entirely possible it does not and that is to be expected because of the ecological fallacy. Thus, application of psychological findings should never be a blind process—it needs to be built upon a solid understanding of who you are and active monitoring of whether something is doing you good or harm. Ultimately, if it's not working, leave it. If it is working, then on behalf of research psychologists, you are welcome :).