Everyday Research Methods

Testing a stereotype about only children (null effect)

Are only children more narcissistic? Credit: stockimagesbank/Shutterstock

People hold all kinds of stereotypes about family structures. For example, lots of people believe that the eldest child in a household is the most responsible. People think that younger children are often spoiled or that middle children are ignored or neglected. Most research on birth order doesn't support these beliefs, though (here's one example, which found that oldest children are a bit smarter, but not any different in personality).

What about only children? Both laypeople and psychologists have sometimes claimed that only children are more likely to become narcissistic. Because they tend to be the focus of parental attention and don't have to negotiate with siblings, onlys are considered to have fewer opportunities to develop humility and social skills. But is the stereotype true?

Here's a journalist's summary of a study that tested this assumption. The study found "... no evidence that only children are more narcissistic than those with brothers or sisters": 

Past research on this topic has turned up conflicting findings. Those earlier studies, however, often had methodological limitations — such as small sample sizes — that made their results less than reliable.

The authors of the new study say their research addresses and corrects those problems. “We can now say with rather high confidence that only children are not substantially more narcissistic than people with siblings,” says Michael Dufner, the study’s lead author and a psychologist at the University of Leipzig

The published article included two studies. The first was meant to establish that people actually do hold the stereotype that only children are more narcissistic: 

... Dufner and his colleagues conducted an online survey of a representative sample of 556 German adults. Their average age was 46, and 105 of them (19 percent) were only children.

The survey was designed to determine the prevalence of the stereotype that people who are only children are more likely to be narcissistic than those with siblings.

The survey found that people do, indeed, tend to judge only children as being more narcissistic, both in terms of their need to be the center of attention (a characteristic known as narcissistic admiration) and in terms of their desire to demean or devalue others to build up their own inflated sense of importance (narcissistic rivalry).

The second study tested the stereotype's accuracy:

For the second part of the study, the researchers analyzed data collected from a representative sample of 1,810 German adults, including 233 without siblings, who answered questions designed to measure their level of narcissism.

The analysis debunked the stereotype. “We found no evidence for the claim that only children are more narcissistic than non-only children,” the researchers write.

Questions

a) What kind of claim is it to say, in the first study, that "people do, indeed, tend to judge only children as being more narcissistic" ? Frequency, association, or causal?

b) Was it important to use a representative sample in Study 1? Why or why not? 

c) The second study was a correlational design. Which two variables did they measure?

d) Why would it be important to use a representative sample for Study 2?

e) Sketch a bar graph of the result that would support the Study 2 statement, "We found no evidence for the claim that only children are more narcissistic than non-only children" 

f) Ask a question about the construct validity of Study 2. Ask a question about the external validity of Study 2.

g) To use terminology from the textbook, Study 2 found a null effect, or no difference. Chapter 11 reviews the potential reasons a study might find a null effect. One reason is a potential ceiling effect on the dependent variable, or DV. Do you think that could be a problem here, with the DV of narcissism? 

h) One way to ensure that a study has enough power and precision to accurately detect a true null effect is to be sure the sample size is large. What was the sample size in this study? 

i) Chapter 11's coverage of null effects focuses on how experiments can sometimes result in null effects, but this study is an example of a correlational study finding a null effect. That is, the authors measured both only-child status and narcissism, and found no relationship. Which of the questions about null effects don't really apply to a correlational study? See the table in Chapter 11 (3rd edition: Table 11.2, 4th edition: Table 11.3). 

To see the original empirical article, go here. 

Does "virtue signaling" change minds?

If a lot of us send virtue signals, it can communicate to others that norms are changing. Credit: SEEphotos7171/Shutterstock"

Among people fighting for racial justice, "virtue signaling" may sometimes be derided as empty action. "Virtue signals" are public messages of support for a social justice cause. They could take the form of a yard sign, a t-shirt, or a social media post. Critics sometimes argue that such messages are easy and cheap. It's easy for a company to put a message on their home page that supports Black Lives Matter. It's not hard to wear a t-shirt that supports a social justice cause. But are these expressions of support all talk and no action?

An article in Time magazine argues that virtue signaling can be more powerful than we think. The authors, psychological scientists Jamil Zaki and Mina Cikara, integrate several studies to make their argument. Here's part of their introduction: 

It’s critical to question people whose most radical act is temporarily changing their profile picture. It’s critical they follow their words with action; the time for talk has passed. But focusing solely on virtue signalers obscures their most important role. Like radio waves, the signals they send are received by someone, and those receivers matter, too.

Zaki and Cikara argue that virtue signaling is an important way of influencing others. If a lot of people change their profile pictures to support BLM, for example, more people will start to believe that this movement is popular and they may adopt it, too:

Opinions can work this way: when a particular viewpoint gets a lot of attention, people assume it’s popular, and shift towards it. We receive signals, and are changed by them.

What studies support their argument? Here's one that the authors summarize: 

As social norms shift, individuals shift with them: adopting popular opinions and behaviors, and dropping ones that fall out of style. Norms are especially powerful as they gain steam. In one set of studies, Gregg Sparkman and Greg Walton presented diners in a cafeteria [either] with evidence that 30% of the U.S. population was vegetarian, or that 30% of the population was newly vegetarian. People who learned about this second, “dynamic social norm” were twice as likely to order a meatless lunch themselves. They saw not just where the crowd was, but where it was going, and didn’t want to be left behind.

Here are some questions about the study summarized above:

a) Was this an experiment or a correlational study? How do you know? (If it's an experiment, what kind of study is it?)

b) What were the key variables in the study? Were they manipulated or measured? 

c) Sketch a small graph of the results being described. Would a bar graph or a scatterplot make more sense?

Here's another study Zaki and Cikara introduce:

Signaling and conformity are not inherently positive. In 2016, the U.S. elected a president whose campaign was jammed with racist talking points. Prejudice subsequently increased, specifically toward groups he targeted (e.g., Muslims, immigrants). 

d) This summary doesn't really help you figure out how the study was designed. But here's a chance to think carefully: What kind of study would we need to conduct in order to test the claim that "prejudice subsequently increased, specifically toward groups he targeted (e.g., Muslims, immigrants)."?  There are three variables you would need to include in your study. What are they? 

 

Suggested answers to selected questions

a) This was probably a posttest-only experiment, because it sounds like they manipulated the message about vegetarianism and measured what foods people took in the cafeteria. Here is a link to the original empirical article. 

d) The key dependent variable in this study is prejudice levels, so that's the first variable. Then, in order to establish that "prejudice increased", you'd need to measure prejudice both before and after the election, so that's another variable. Finally, in order to show that it increased specifically toward groups he targeted, you'd need to measure different types of groups (Muslims, immigrants, as well as other potential groups that Trump did not deride in his campaign). You can review the Crandall article here. Do their results really support what Zaki and Cikara are saying about it? (Pay attention to the difference between people's actual prejudice and the normativity of prejudice.)