Are smartphones making young people lonely, anxious and depressed? Are teens spending time on phones instead of dating, driving, or drinking? That's the argument of a new data-based book by psychologist Jean Twenge.
You can watch a video interview with Dr. Twenge on CNN here, complete with some of the graphs from Dr. Twenge's recent book on this topic, which reflects her research. There's also an article in The Atlantic here, which contains a condensed argument from the book.
Several graphs presented in the CNN interview depict patterns of teenage behavior over time, from nationally representative surveys of youth. The graphs show how various healthy activities such as "hanging out with friends" dropped starting in 2012. Twenge's explanation is that 2012 is the first year that more than 50% of Americans owned smartphones. Twenge argues that instead of going out with friends, driving, or being independent, today's teenagers are staying home and connecting with friends only via Snapchat and Instagram.
a) The graph in the CNN story (see minute 1:50 to 2:05; and also here) shows several trends over time. These figures come from a study that is quasi-experimental. Which type of quasi-experiment does this seem to be?
b) Take a look at the "More likely to feel lonely" figure, at minute 2:02. (again, you can also see it here, by scrolling down) The change in loneliness after 2007 has been described as "dramatic" and "precipitous". What do you think? Specifically, look at the y-axis of the graph. How dramatic would the data look if the axis ranged from, say, 0 to 100?
c) Twenge's argument is that the advent of cell phones in 2012 is responsible for decreased social contact and increased loneliness, anxiety, and depression of youth. What might be some plausible alternative explanations for the pattern, other than cell phones? (that is, what are some internal validity threats?)
The data above are longitudinal data, collected over time. Twenge's research has also included correlational studies collected in one group of teenagers at a single point in time. This report in the Washington Post presents the results of an empirical study that found, among other things, that teens who spent more time doing Internet, texting, computer games, or social media were lower in happiness.
d) Scroll down to the graph created by the Washington Post, which is titled "What makes teens happy?" You'll see that each bar represents a correlation between one use of time and teen happiness. What does a gray bar, or negative correlation mean (For example, what does the -0.11 correlation mean for Internet? Sketch a little scatterplot of this correlation.
e) In the same graph, what does a blue bar, or positive correlation mean (For example, what does the 0.14 correlation mean for Sports or exercise?) Sketch a little scatterplot of this correlation.
f) Select the correlation mentioned in d.Does this correlation, on its own, allow us to conclude that time on the Internet causes lower levels of happiness? What third variables might be responsible for this negative correlation? What about temporal precedence of the two variables?
g) How might you describe the effect size of these correlations–are they weak, moderate or strong? How do you know?
h) Consider both the longitudinal data (in Questions a, b, and c) and the correlational data (in questions d-g). Both types of studies support the same conclusion, which make them an example of "Pattern and Parsimony." Explain why this is the case, in your own words.
Instructors: You and your students might also be interested in a curvilinear relationship described in the same Post piece:
The report’s findings were not all dire: Teenagers who get a small amount of exposure to screen time, between one and five hours a week, are happier than those who get none at all. The least happy ones were those who used screens for 20 or more hours a week.