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Have you ever watched dance challenge videos on TikTok? If so, you probably noticed the skill and appearance of the dance model. Some psychologists have started to study how TikTok dance models affect viewers. A set of three studies asked, can the size of the dancer on TikTok influence the body satisfaction of a viewer? Journalists at PsyPost wrote up a summary of this empirical work. The research was originally published in the journal, Computers in Human Behavior; may be paywalled.
The theory behind the study is related to the potential of social media to impact body esteem:
Media, especially its portrayal of the “thin ideal,” where extremely slim bodies are considered attractive, has a significant impact on shaping these negative body perceptions. With the rise of social media platforms like TikTok, researchers are curious about how this new form of media might influence people’s body image.
Here's a description of the first study. As you read this description, try to identify the variables in the study:
...the researchers recruited 262 women aged between 18 and 25 years for an online experiment. The participants were randomly assigned to watch TikTok videos featuring thin dancers, large dancers, or videos of animals (the control condition). [Both before and after] watching the videos, participants rated their weight satisfaction, overall appearance satisfaction, and body shape satisfaction.
Body satisfaction significantly increased after watching videos featuring large dancers and control videos (videos unrelated to body appearance). However, after watching videos of thin dancers, body satisfaction showed a slight decrease.
a) Use this chart to identify Study 1's variables (Hint: There are one IV and three DVs)
Variable name | What are the variable's possible levels? |
Is this manipulated or measured? | Is this an IV or a DV? | For IVs: is it within groups or independent groups? |
b) Which kind of experiment is Study 1: Posttest only? Pretest/posttest? Concurrent measures? Repeated measures? How do you know?
c) Sketch a bar graph or line graph of the results they described (select one of the three DVs). Don't forget to plot both pretest and postest data.
The researchers did Study 2 to replicate Study 1:
Study 2 largely replicated the findings from Study 1. Watching videos featuring large dancers led to increased body satisfaction, while watching videos featuring thin dancers resulted in decreased body satisfaction.
Study 2 also measured the potential mechanism, or mediator, of social comparison (how often someone compares their appearance to those of others.). Study 2 found:
A majority of participants in the thin dancer condition engaged in upward comparison (comparing themselves negatively to the dancers), while a majority of participants in the large dancer condition engaged in downward comparison (comparing themselves positively to the dancers).
One potential internal validity threat to both Study 1 and Study 2 is that participants were told the study was about body satisfaction. In addition, the pretest-postest nature of the design may have nudged participants to report changes in line with the study's goals.
Study 3 attempted to correct this issue with a posttest-only design, and by telling participants that the study was actually about how engaging different TikTok videos are.
d) What is the name for this type of internal validity threat?
e) Why would a posttest-only design help control for this internal validity threat?
Here's the journalist's summary:
In Study 3, the researchers recruited 375 women aged between 18 and 25 years and randomly assigned them to watch either TikTok videos of thin dancers or TikTok videos of large dancers. Participants were told that the study aimed to investigate the engagement of TikTok videos. After watching the videos, the participants completed the same measures of body satisfaction used in the previous studies.
Even after concealing the true purpose of the study, the results consistently indicated that watching videos of thin dancers led to lower body satisfaction compared to videos of large dancers.
f) Reread the summary of Study 3 and identify its variables on the table below:
Variable name |
What are the variable's possible levels? |
Is this manipulated or measured? | Is this an IV or a DV? | For IVs: is it within groups or independent groups? |
g) Graph the results of one of the dependent variables in Study 3.
h) What do you think of this set of studies? Ask questions about the four aspects of validity.
Specifically, when you address statistical validity, use terms like replication and effect size.
When you address internal validity, think about how the study rules out most internal validity threats.
When you address construct validity, ask a question about the measurement of the dependent variables.
When you address external validity, think about the samples used in these studies.
Here's how the researchers concluded an interview about their studies:
“I would like to add that this study shows that watching TikTok videos is not universally negative and that there are positive and negative effects,” Joiner said. “The findings also raise the possibility that TikTok could change its algorithm and show a wider variety of body types, and this could have a major public health benefits. Body dissatisfaction is major risk factor for eating disorders and eating disorders have the highest mortality rate of all psychiatric diseases due to medical complications or suicide.”